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 Federal  Communications  Commission  FCC  05-  199 
 Report  To  Congress 
 The  Satellite  Home  Viewer  Extension  And  Reauthorization  Act  Of  2004 


 Study  Of  Digital  Television  Field  Strength  Standards 
 And  Testing  Procedures 
 ET  Docket  No.  05-  182 
 Adopted:  December  6,  2005  Released:  December  9,  2005 
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 Table  of  Contents 
 Paragraph  I.  SUMMARY.............................................................................................................................................  1 
 II.  BACKGROUND  .....................................................................................................................................  3  III.  THE  DIGITAL  TV  SIGNAL  STRENGTH  STANDARDS..................................................................  10 
 IV.  DIGITAL  TELEVISION  FIELD  STRENGTH  MEASUREMENT  PROCEDURES  ........................  109  V.  PREDICTIVE  MODELING................................................................................................................  132 


 Page  APPENDIX  A 
 Section  339(  c)(  1)  of  the  Communications  Act  of  1934,  As  Amended................................................  A-  1  APPENDIX  B 
 Parties  Submitting  Comments  and  Reply  Comments..........................................................................  B-  1  APPENDIX  C 
 Tests  of  ATSC  8-  VSB  Reception  Performance  of  Consumer  Digital  Television  Receivers  Available  in  2005.................................................................................................................................  C-  1 
 APPENDIX  D  Notice  of  Inquiry..................................................................................................................................  D-  1 
 APPENDIX  E  Comments  and  Reply  Comments  to  Notice  of  Inquiry........................................................................  E-  1 


 ACKNOWLEDGEMENTS 
 This  Report  was  prepared  under  the  leadership  of  the  Office  of  Engineering  and  Technology,  in  cooperation  with  the  Media  Bureau. 


 Office  of  Engineering  and  Technology 
 Ron  Chase,  Bruce  Franca,  Charles  Iseman,  Ira  Keltz,  Stephen  Martin,  Alan  Stillwell,  David  Sturdivant 


 Media  Bureau 
 Eloise  Gore 
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 "unserved"  by  their  local  stations.  In  the  SHVA,  Congress  linked  the  definition  of  "unserved  households"  to  a  Commission-  defined  measure  of  analog  television  signal  strength  known  as  "Grade  B  intensity."  3 
 The  Grade  B  signal  intensity  standard,  as  set  forth  in  Section  73.683(  a)  of  the  Commissions  rules,  is  used  to  identify  a  geographic  contour  that  defines  an  analog  television  stations  service  area.  4  For  digital 
 television  stations,  the  counterpart  to  the  Grade  B  signal  intensity  standards  for  analog  television  stations  are  the  values  set  forth  in  Section  73.622(  e)  of  the  Commission's  Rules  describing  the  DTV  noise-  limited 
 service  contour.  5 
 4.  The  new  Section  339  requires  the  Commission  to  conduct  an  inquiry  regarding  whether,  for  purposes  of  identifying  if  a  household  is  unserved  by  a  digital  signal  under  Section  119(  d)(  10)  of  Title  17, 


 United  States  Code,  the  digital  signal  strength  standards  in  Section  73.622(  e)(  1)  of  the  Commissions  rules,  or  the  testing  procedures  in  Section  73.686(  d)  of  the  Commissions  rules,  should  be  revised  to  take 
 into  account  the  types  of  antennas  that  are  available  to  consumers.  6  In  1999,  the  Commission  adopted  a  Report  and  Order  (SHVA  Report  and  Order)  addressing  three  major  issues  that  arose  in  the  context  of  the 
 SHVA  and  several  pending  court  actions  and  petitions  to  the  Commission.  7  First,  it  affirmed  the  existing  definition  of  a  signal  of  Grade  B  intensity  for  use  in  determining  eligibility  for  reception  of  distant 
 network  signals.  Second,  the  Commission  adopted  rules  for  determining  whether  a  household  is  able  to  receive  an  analog  television  signal  of  this  strength.  8  In  particular,  the  Commission  adopted  rules 
 establishing  a  standardized  method  for  measuring  the  strength  of  analog  television  signals  on-  site  at  individual  locations.  And  finally,  it  endorsed  a  method  for  predicting  the  strength  of  such  signals  that 
 could  be  used  in  place  of  actually  taking  measurements.  9 
 5.  As  added  under  the  Satellite  Home  Viewer  Improvement  Act  of  1999  (SHVIA),  10  the  then-new  Section  339(  c)(  3)  of  the  Communications  Act  required  that  the  Commission  develop  and  prescribe 


 by  rule  a  point-  to-  point  predictive  model  for  reliably  and  presumptively  determining  the  ability  of  individual  locations  to  receive  signals  in  accordance  with  the  signal  intensity  standard  in  effect  under 
 Section  119(  d)(  10)(  A)  of  Title  17  of  the  Unites  States  Code,  that  is,  the  Grade  B  standards.  11  Section  339(  c)(  3)  further  required  that  the  Commission  rely  on  the  ILLR  model  which  the  Commission  had 
 earlier  developed  for  such  predictions  and  that  the  Commission  ensure  that  such  model  takes  into  account 
 3  See  17  U.  S.  C.    119(  d)(  10)(  A);  47  C.  F.  R.    73.  683(  a). 
 4  47  C.  F.  R.    73.683(  a);  see  also  47  C.  F.  R.    73.  684. 
 5  47  CFR    73.  622(  e);  see  also  47  CFR    73.  625(  b)  (determining  coverage).  As  set  forth  in  Section  73.  622(  e),  a 
 stations  DTV  service  area  is  defined  as  the  area  within  its  noise-  limited  contour  where  its  signal  strength  is  predicted  to  exceed  the  noise-  limited  service  level. 


 6  47  U.  S.  C.    119(  d)(  10);  47  C.  F.  R.    73.  622(  e)(  1);  47  C.  F.  R.    73.  686(  d). 
 7  Satellite  Delivery  of  Network  Signals  to  Unserved  Households  for  Purposes  of  the  Satellite  Home  Viewer  Act, 
 CS  Docket  No.  98-  201,  Report  and  Order,  14  FCC  Rcd  2654,  2655  at    2  (1999)  (SHVA  Report  and  Order);  Order  on  Reconsideration,  14  FCC  Rcd  17373  (1999). 


 8  SHVA  Report  and  Order,  14  FCC  Rcd  at  2656    4. 
 9  SHVA  Report  and  Order,  14  FCC  Rcd  at  2657    8. 
 10  See  Consolidated  Appropriations  Act  for  2000,  Pub.  L.  106-  113,    1000(  9),  113  Stat.  1501  (enacting  S.  1948, 
 including  the  Satellite  Home  Viewer  Improvement  Act  of  1999,  Title  I  of  the  Intellectual  Property  and  Communications  Omnibus  Reform  Act  of  1999,  relating  to  copyright  licensing  and  carriage  of  broadcast  signals 


 by  satellite  carriers,  codified  in  scattered  sections  of  17  and  47  U.  S.  C.).  Section  1008(  a)  of  SHVIA  added,  inter  alia,  new  Section  339  (  Carriage  of  Distant  Television  Stations  by  Satellite  Carriers)  to  the  Communications  Act 
 of  1934,  47  U.  S.  C.    151  et  seq.  11 
 See  also  47  C.  F.  R.    73.  683(  a)  (Grade  B  field  strength  contours  for  channels  2-  6,  7-  13,  and  14-  69). 
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 terrain,  building  structure,  and  other  land  cover  variations.  In  response  to  these  provisions,  the  Commission  adopted  a  First  Report  and  Order  in  May  2000  in  which  it  amended  its  rules  to  prescribe  use 
 of  an  improved  point-  to-  point  ILLR  model  for  establishing  whether  individual  households  are  eligible  to  receive  distant  analog  network  television  signals.  12  This  model  includes  adjustments  for  land  use  and 
 land  cover  loss  values.  The  rules  also  provide  for  a  neutral  and  independent  entity  to  evaluate  the  qualifications  of  potential  testers  to  conduct  on-  site  signal  strength  measurements  in  cases  where  a 
 network  television  station  denies  a  subscribers  request  for  a  waiver  of  the  ILLR  prediction  that  the  viewer  is  served. 


 6.  In  addition,  in  the  SHVIA  Congress  directed  the  Commission  to  conduct  an  inquiry  and  prepare  a  report  regarding  the  broadcast  TV  signal  strength  standard  used  for  satellite  carrier  purposes. 
 The  then-  new  Section  339(  c)(  1)  of  the  Communications  Act  required  that  this  investigation  evaluate  all  possible  standards  and  factors  for  determining  eligibility  to  receive  retransmitted  network  station  signals 
 and,  if  appropriate,  recommend  modification  of,  or  alternative  standards  or  factors,  to  the  Grade  B  intensity  standard  for  analog  television  signals  and  to  make  a  further  recommendation  relating  to  an 
 appropriate  standard  for  digital  television  signals.  13  In  response  to  this  directive,  the  Commission  inquired  into  and  evaluated  the  possible  standards  and  factors  for  determining  eligibility  of  households  to 
 receive  retransmissions  of  network  station  signals  by  satellite  carriers.  It  specifically  considered  whether  to  recommend  modifications  to,  or  alternative  standards  or  factors  for,  the  Grade  B  intensity  standard  for 
 analog  television  signals.  On  November  29,  2000,  the  Commission  issued  a  Report  to  Congress  (SHVIA  Report)  in  which  it  recommended  retention  of  the  Grade  B  signal  intensity  standard  and  eight  of  the  nine 
 planning  factors  used  in  developing  that  standard  as  the  basis  for  predicting  whether  a  household  is  eligible  to  receive  retransmitted  distant  TV  network  analog  signals  under  the  SHVIA.  14  The  Commission 
 recommended  modification  of  the  remaining  planning  factor  (time  fading)  by  replacing  the  existing  fixed  values  with  location-  dependent  values  determined  for  the  actual  receiving  locations  using  the  Individual 
 Location  Longley-  Rice  (ILLR)  prediction  model.  With  regard  to  digital  signals,  the  Commission  found  that  it  would  be  premature  to  construct  a  distant  network  signal  eligibility  standard  for  DTV  signals  at  that 
 time.  The  Commission  therefore  recommended  that  establishment  of  a  distant  network  signal  eligibility  standard  for  digital  signals  be  deferred  until  such  time  as  more  substantial  DTV  penetration  is  achieved 
 and  more  experience  is  gained  with  DTV  operation.  15 
 7.  In  December  2004,  Congress  enacted  the  SHVERA,  which  revised  the  statutory  provisions  of  the  SHVA  and  SHVIA,  including  Section  339  of  the  Communications  Act  of  1934.  16  Under  the 


 12  See  In  the  Matter  of  Establishment  of  an  Improved  Model  for  Predicting  the  Broadcast  Television  Field  Strength 
 Received  at  Individual  Locations,  First  Report  and  Order  in  ET  Docket  No.  00-  11  (ILLR  First  Report  and  Order),  15  FCC  Rcd  12118  (2000);  recon.  Memorandum  Opinion  and  Order  in  ET  Docket  No.  00-  11,  19  FCC  Rcd  9963 


 (2004);  appeal  pending,  EchoStar  L.  L.  C.  v.  FCC  &  USA,  No.  04-  1304  (D.  C.  Circuit).  13 
 See  47  U.  S.  C.    339(  c).  See  also  17  U.  S.  C.    119(  a)(  2)(  b)  and  (d)(  10).  Section  339(  c)  sets  forth  the  circumstances  in  which  Direct  Broadcast  Satellite  (DBS)  subscribers  are  eligible  to  receive  retransmission  of 


 distant  network  signals.  See  also  47  U.  S.  C.  339(  c)(  1)  as  amended  by  the  SHVERA.  14 
 See  Report  to  Congress,  In  the  Matter  of  Technical  Standards  for  Determining  Eligibility  for  Satellite  Delivered  Network  Signals  Pursuant  to  the  Satellite  Home  Viewer  Improvement  Act,  15  FCC  Rcd  24321  (2000).  The  eight 


 planning  factors  recommended  for  retention  were:  thermal  noise,  transmission  line  loss,  receiving  antenna  gain,  dipole  factor,  terrain  factor,  urban  noise,  signal-  to-  noise  ratio,  and  urban  noise.  The  development  of  the  Grade  B 
 signal  intensity  standard  and  its  use  in  connection  with  the  authorization  of  analog  television  stations  and  the  determination  of  stations  service  areas  and  contours  is  also  discussed  in  greater  detail  in  the  SHVIA  Report. 


 15  Id. 
 16  47  U.  S.  C.    339. 
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 III.  THE  DIGITAL  TV  SIGNAL  STRENGTH  STANDARDS 
 10.  Eligibility  to  receive  distant  network  signals  retransmitted  by  a  satellite  carrier  has  been,  in  principle,  based  on  the  inability  of  a  household  subscribing  to  a  Direct  Broadcast  Satellite  (DBS)  service 
 is  not  able  to  receive  network  signals  over-  the-  air  at  its  location  using  a  receiving  system  that  conforms  to  the  assumed  receiving  system  on  which  the  television  service  area  standards  are  based.  23  If  a  household  is 
 not  able  to  receive  a  network  signal  at  a  field  strength  level  equal  to  or  greater  than  the  TV  service  area  Grade  B  (analog  TV)  or  noise-  limited  (digital  TV)  standards,  that  household  may  be  eligible  to  receive 
 the  signal  of  a  distant  station  affiliated  with  that  network  that  is  retransmitted  on  the  households  DBS  service  if  it  meets  other  criteria  for  eligibility.  Congress  has  asked  the  Commission  to  investigate  whether 
 the  noise-  limited  DTV  service  standard  should  be  revised  to  take  into  account  the  types  of  antennas  that  are  available  to  consumers.  In  considering  this  issue,  the  Commission  must  consider:  1)  whether  to 
 account  for  the  fact  that  an  antenna  can  be  mounted  on  a  roof  or  placed  in  a  home  and  can  be  fixed  or  capable  of  rotating,  2)  whether  there  is  a  wide  variation  in  the  ability  of  reasonable  priced  consumer 
 digital  television  sets  to  receive  over-  the-  air  signals  such  that  at  a  given  signal  strength  some  may  be  able  to  display  high-  quality  pictures  while  others  may  not,  whether  such  variation  is  related  to  the  price  of  the 
 television  set,  and  whether  such  variation  should  be  factored  into  setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate  digital  signal,  and  3)  whether  to  account  for  factors  such 
 as  building  loss,  external  interference  sources,  or  undesired  signals  from  both  digital  television  and  analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets,  foliage,  and  man-  made 
 clutter.  In  this  section,  we  discuss  the  digital  TV  signal  strength  standards  and  evaluate  the  factors  underlying  those  standards,  including  those  specified  in  Section  204,  in  light  of  our  Inquiry  and  study. 
 We  also  consider  whether  any  adjustments  to  those  standards  are  warranted  in  light  of  our  findings. 
 A.  The  DTV  Service  Area  Field  Strength  Intensity  Standards 
 11.  As  indicated  above,  the  service  areas  of  broadcast  television  stations,  in  the  absence  of  interference,  are  defined  on  the  basis  of  a  concept  known  as  noise-  limited  service.  Under  this  concept, 


 a  TV  stations  service  extends  to  cover  geographic  locations  out  to  the  edge  of  where  reception  is  no  longer  possible  because  of  interference  from  background  electrical  noise.  The  background  noise  limiting 
 reception  of  service  arises  both  from  the  environment  and  from  within  the  equipment  used  to  receive  service.  Both  the  analog  TV  Grade  B  field  strength  intensity  standards  and  the  digital  TV  noise-  limited 
 field  strength  intensity  standards  are  defined  on  this  basis.  These  standards  were  developed  in  the  early  days  of  both  methods  of  television  modulation  as  a  key  component  of  the  Commissions  television  station 
 channel  allotment  and  service  area  regulations.  24  The  DTV  service  area  definitions  further  specify  that  service  is  considered  to  be  present  in  areas  within  the  noise-  limited  contour  where  signal  strength  is 


 23  The  criteria  for  eligibility  to  receive  a  distant  network  signal  from  a  DBS  service  also  include  factors  in  addition 
 to  the  ability  of  a  household  to  receive  that  network  signal  over-  the-  air  from  a  local  TV  station,  see  Section  339  of  the  Communications  Act,  47  U.  S.  C.    339. 


 24  See  Television  Broadcast  Service,  Third  Notice  of  Further  Proposed  Rule  Making,  Appendix  B,  16  Fed.  Reg. 
 3072,  3080  (April  7,  1951),  adopted  in  Amendment  of  Section  3.606  of  the  Commissions  Rules  and  Regulations  and  Amendment  of  the  Commissions  Rules,  Regulations,  and  Engineering  Standards  Concerning  the  Television 


 Broadcast  Service  in  the  Band  470  to  890  MHz  for  Television  Broadcasting,  Sixth  Report  and  Order,  41  FCC  148  (1952);  see  also  Advanced  Television  Systems  and  Their  Impact  upon  the  Existing  Television  Broadcast  Service, 
 Sixth  Report  and  Order  in  MM  Docket  No.  87-  268,  12  FCC  Rcd  14588  (1997)  (DTV  Sixth  Report  and  Order),  at    183-  196. 
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 predicted  to  exceed  the  noise-  limited  signal  level  using  the  terrain-  dependent  Longley-  Rice  point-  to-  point  propagation  model.  25 
 12.  The  field  strength  of  television  signals  decreases  with  distance  from  the  transmitter  and  varies  across  individual  locations  and  time.  At  locations  close  to  a  stations  transmitter  the  variation  of  signal 
 strength  across  time  and  location  are  generally  not  great.  However,  as  distance  increases,  the  variability  of  the  available  signal  strength  with  both  location  and  time  increases  significantly.  At  the  edge  of  a 
 stations  service  area,  its  signal  will  be  available  in  some  locations  more  of  the  time  than  at  others.  Historically,  if  service  is  not  available  all,  or  most  of  the  time,  it  is  simply  considered  not  available. 
 Under  both  the  analog  Grade  B  and  digital  noise-  limited  F(  50,90)  service  standards,  an  acceptable  television  picture  and  sound  service  is  available  at  50%  of  the  locations  for  90%  of  the  time  at  locations 
 on  the  outer  edge  of  a  stations  service  area.  The  signal  strength  values  of  the  analog  TV  standards  were  selected  to  provide  service  at  these  levels  of  availability  and  the  digital  television  standards  were  specified 
 to  enable  DTV  stations  to  replicate  their  analog  service.  26 
 13.  The  noise-  limited  digital  TV  field  strength  standards  were  derived  from  a  set  of  assumptions  for  the  several  technical  planning  factors  that  are  present  in  a  typical  DTV  receiving  system  and  for  a 


 defined  level  of  service.  The  DTV  receiving  system  includes  all  elements  in  the  electrical  path  from  the  point  where  a  DTV  signal  is  converted  from  electromagnetic  energy  to  electric  energy  at  the  receive 
 antenna  to  the  point  in  the  tuning  function  of  a  TV  set  where  the  received  signal  is  delivered  to  the  demodulator  that  produces  the  19.39  mbps  digital  TV  bitstream.  The  effect  of  each  of  the  elements  in  the 
 receiving  system  and  the  factors  for  time  and  location  variability  are  summed  to  determine  the  minimum  signal  level  that  must  be  available  over-  the-  air  to  provide  an  F(  50,90)  level  of  service  at  the  edge  of  a 
 stations  noise-  limited  service  area  contour.  These  factors  and  their  assumed  values  as  used  in  establishing  the  DTV  noise-  limited  service  area  field  strength  intensity  standards  are:  27 


 25  Guidance  for  evaluating  DTV  coverage  areas  using  the  Longley-  Rice  methodology  is  provided  in  OET  Bulletin 
 No.  69,  which  is  available  through  the  Internet  at  the  Commissions  website,  http://  www.  fcc.  gov/  oet/  info/  documents/  bulletins/. 


 26  See  DTV  Sixth  Report  and  Order,  supra  note  24,  at    29-  33  and  Appendix  B. 
 27  See  DTV  Sixth  Report  and  Order,  supra  note  24,  at  Appendix  A. 
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 *  Antenna  placement  is  assumed  outdoors  at  9  meters  (30  feet).  **  The  required  S/  N  value  stated  in  the  DTV  Sixth  Report  and  Order  and  OET  Bulleting  No.  69 
 is  15.  That  value  was  rounded  from  the  15.19  value  set  forth  in  the  FCC  Advisory  Committee  on  Advanced  Television  Services  (ACATS)  Final  Technical  Report  (October  31,  1995)  at 
 Table  5.1.  ***  The  time  variability  factor  is  defined  as  the  difference  between  the  F(  50,10)  minus  F(  50,50), 
 where  these  two  values  are  determined  from  the  charts  in  Section  73.699  of  the  Commissions  rules,  47  C.  F.  R.    73.699.  This  factor  is  a  function  of  the  distance  between  the  transmitting  and 
 receiving  antennas. 
 14.  Using  the  factors  in  the  above  chart,  the  minimum  signal  level  that  needs  to  be  present  at  the  input  terminal  of  a  television  receiver,  to  provide  service  is  the  sum  of  the  thermal  noise,  the  receiver 
 noise  figure,  and  the  receiver  signal-  to-  noise  (S/  N)  ratio,  that  is: 
 Minimum  receiver  signal  level  R  =  Nt  +  Ns+  S/  N  for  low  and  high  VHF  channels  =  -106.2  +  10  +  15.2  =  -81.0  dBm 


 for  UHF  channels  =  -106.2  +  7  +  15.2  =  -84.0  dBm 
 15.  Considering  the  entire  receiving  system,  the  minimum  field  strength  needed  to  be  available  at  the  antenna  is  the  sum  of  the  minimum  signal  level  needed  at  the  receiver,  the  downlead  line  loss,  and  the 
 dipole  factor,  less  the  antenna  gain: 
 Minimum  field  strength  to  receive  service  MFS  =  R  +  L  +  Kd    G  for  low  VHF  channels  =  -81.0  dBm  +  1  +  111.8    4  =  27.8  dBV/  m 


 for  high  VHF  channels  =  -81.0  dBm  +  2  +  120.8    6  =  35.8  dBV/  m  for  UHF  channels  =  -84.0  dBm  +  4  +  130.8    10  =  40.8  dBV/  m 


 16.  Rounding  to  the  nearest  decibel,  we  have  28,  36,  and  41  dBu  as  the  minimum  field  strength  standards  for  channels  in  the  low  VHF,  high  VHF,  and  UHF  channel  bands,  respectively.  As  indicated  in 
 the  chart  of  planning  factors,  above,  no  adjustments  were  needed  to  compensate  for  time  or  location  variability  beyond  that  already  afforded  by  F(  50,  90)  level  of  service. 


 Planning  Factor:  Symbol  Low  VHF  (2-  6)  High  VHF  (7-  13)  UHF  (14-  69) 
 Geometric  Mean  Frequency  (MHz)  F  69  194  615 
 Dipole  Factor  (dBm-  dBu)  Kd  -111.8  -120.8  -130.8 
 Thermal  Noise  (dBm)  Nt  -106.2  -106.2  -106.2 
 Antenna  Gain  (dB)  G  4  *  6  *  10  * 
 Front-  to-  back  ratio  (dB)  (ratio  of  forward  gain  to  maximum 


 response  over  rear  180  o  )  FB  10  12  14  Downlead  line  loss  (for  50  ft/  15  m. 
 of  coaxial  cable  (dB)  L  1  2  4  System  (receiver)  noise  figure  (dB)  Ns  10  10  7 
 Required  receiver  S/  N  ratio  (dB)  S/  N  15.2**  15.2**  15.2** 
 Time  variability  factor  (90%  availability)  (dB)  dT  0***  0***  0*** 


 Location  variability  factor  (50%  availability)  (db)  dL  0  0  0 
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 Federal  Communications  Commission  FCC  05-  199 
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 B.  Review  of  the  DTV  Field  Strength  Intensity  Standards 
 17.  Several  parties  commenting  in  the  Inquiry  indicate  that  the  Commission  should  continue  to  determine  whether  a  household  is  unserved  based  on  the  current  assumed  planning  factors,  which  include 


 an  assumption  that  an  outdoor  stationary  antenna  is  mounted  at  a  height  of  9  meters.  28  The  National  Association  of  Broadcasters  (NAB)  states  the  assumptions  made  in  the  Commissions  DTV  planning 
 factors  and  in  the  Longley-  Rice  model  about  household  reception  equipment  are  reasonable  and  realistic.  29  In  particular,  NAB  asserts  that,  as  was  the  case  for  analog  television,  the  Commissions  digital 
 transition  proceeding  has  always  assumed  that  consumers  in  fringe  areas  would  use  rooftop  antennas  that  are  properly  oriented  to  achieve  the  best  reception  from  the  station  in  question.  30  As  a  consequence,  NAB 
 reasons  that  broadcasters  have  built  transmission  systems  based  on  these  Commission  assumptions  and  standards  and,  thus,  it  would  now  be  unfair  to  assume,  as  a  DTV  planning  factor,  that  viewers  will  use 
 indoor  antennas.  31  Also,  NAB  contends  that,  because  rooftop  antennas  provide  much  better  service  than  indoor  antennas,  households  have  long  used  rooftop  antennas  to  achieve  over-  the-  air  reception, 
 particularly  if  the  household  is  at  some  distance  from  the  transmitting  tower.  It  notes  that  rural  households  often  rely  on  small  towers    with  over-  the-  air  antennas  placed  considerably  higher  than  the 
 assumed  rooftop  level    to  receive  a  strong  signal  from  stations  several  dozen  miles  away.  32  Additionally,  NAB  asserts  that  satellite  dish  antennas  can  only  be  used  outdoors,  usually  atop  a  roof,  and,  therefore,  it 
 would  be  egregiously  discriminatory  for  the  Commission  to  conclude  that  while  satellite  subscribers  are  expected  to  rely  on  a  rooftop  antenna  for  their  satellite  reception,  they  cannot  be  expected  to  do  the  same 
 to  pick  up  over-  the-  air  signals.  33  The  Consumer  Electronics  Association  (CEA)  submits  that  broadcast  television  households  should  have  a  right  to  a  consistent  definition  of  whether  their  households  are 
 considered  served  by  a  TV  station.  34 
 18.  In  their  comments,  the  ABC,  CBS,  and  NBC  Television  Affiliate  Association  (Network  Affiliates)  state  that  the  Commissions  DTV  planning  factors  established  appropriate  signal  strength 


 thresholds  for  reception  of  real-  world  DTV  signals.  35  These  planning  factors,  Network  Affiliates  assert,  contain  a  safety  margin  to  ensure  that  quality  DTV  reception  is  achievable  precisely  where  the 


 28  The  Association  for  Maximum  Service  Television,  Inc.  (MSTV)  comments  at  2  (Commission  should  reaffirm 
 the  DTV  signal  strength  standards  for  determining  DTV  service  availability  and  for  identifying  underserved  households  pursuant  to  SHVERA);  Consumer  Electronics  Association  (CEA)  comments  at  3  (although  antenna 


 type  and  placement  is  a  critical  factor  in  DTV  reception,  it  should  not  be  considered  in  determining  household  eligibility  for  distant  DTV  network  signal  reception;  instead,  such  eligibility  should  be  determined  based  on  the 
 failure  of  a  signal  of  at  least  a  given  field  strength  to  be  present  at  a  specified  height  above  the  location);  NAB  comments,  passim;  and  Network  Affiliates  comments,  passim. 


 29  NAB  comments  at  16. 
 30  Id.  at  14  and  18-  20.  NAB  points  out  that,  in  comparison  to  outdoor  antennas,  indoor  antennas  do  not  perform  as 
 well  at  receiving  over-  the-  air  TV  signals,  have  lower  gain,  are  placed  in  inferior  locations  for  over-  the-  air  reception,  are  typically  nondirectional,  and  are  affected  by  the  movement  of  people  within  the  room.  Id.  at  16-  17. 


 31  Id.  at  18-  19. 
 32  Id.  at  17. 
 33  Id.  at  18. 
 34  See  CEA  comments  at  2. 
 35  Network  Affiliates  comments  at  13-  38. 
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 Federal  Communications  Commission  FCC  05-  199 
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 Commission  expects  it  to  be,  namely,  in  the  replicated  analog  TV  service  area.  36  With  these  considerations  in  mind,  and  realizing  that  satellite  antennas  must  be  mounted  outdoors  and  must  be 
 oriented  to  the  satellite  for  proper  reception,  the  Network  Affiliates  contend  that  it  would  be  inappropriate  to  essentially  penalize  local  TV  stations  for  those  consumers  who  were  only  willing  to 
 install  an  indoor  antenna  (or  an  antenna  that  was  incapable  of  being  oriented  to  the  desired  signal),  especially  when  those  consumers  are  willing  to  take  additional,  necessary  steps  to  obtain  adequate 
 satellite  reception.  37  Moreover,  they  state  that  real-  world  equipment,  including  fifth  generation  DTV  receivers  whose  performance  in  terms  of  whether  they  are  able  to  receive  service  does  not  vary  by  price, 
 demonstrates  that  the  Commissions  current  signal  strength  thresholds  are  more  than  adequate  to  receive  a  high-  quality  digital  picture.  38  The  MSTV,  the  NAB  and  the  Network  Affiliates  argue  that  there  is  no  need 
 for  the  Commission  to  consider  modifying  the  inherent  assumptions  regarding  DTV  antenna  receiving  systems  in  the  DTV  planning  factors  and  that  it  should  recommend  to  Congress  that  the  DTV  signal 
 strength  standards  remain  the  same  for  purposes  of  determining  whether  a  household  is  unserved  by  a  digital  signal  for  purposes  of  17  U.  S.  C.    119(  d)(  10).  39  CEA  argues  that  it  is  not  appropriate  for  the 
 Commission  to  take  into  consideration  that  an  antenna  can  be  mounted  on  a  roof  or  placed  inside  a  home  or  can  be  fixed  or  capable  of  rotating.  It  submits  rather  that  it  is  necessary  and  sufficient  for  the 
 Commission  to  state  that  a  given  field  strength,  predicted  or  measured,  at  a  known  height  above  the  location  determines  whether  a  household  is  served.  40 


 19.  Other  commenting  parties  assert  that  the  planning  factors  should  be  substantially  modified  or  are  otherwise  insufficient  for  use  in  determining  household  eligibility  pursuant  to  SHVERA.  41  EchoStar 
 argues  that  the  signal  strength  standard  should  be  revised  to  account  for  DTV  receiver  performance,  man-made  noise,  indoor  antenna  use,  and  the  lack  of  rotation  in  outdoor  antennas.  42  It  submits  that  the  signal 
 sensitivities  of  the  current  generation  of  receivers  are  worse  than  the  signal  sensitivities  assumed  in  the  DTV  planning  factors  and  that  as  a  result  many  consumer  DTV  sets  may  not  be  able  to  display  a  DTV 
 picture  even  when  the  signal  strength  meets  the  Commissions  standards.  EchoStar  also  argues  that  for  the  low  VHF  channels  man-  made  noise  was  not  adequately  taken  into  account  in  the  planning  factors  and 
 that  as  a  result  the  Commission  did  not  build  in  a  sufficient  margin  for  noise  when  it  set  the  signal  strength  standard  for  those  channels.  With  regard  to  indoor  antenna,  EchoStar  argues  that  an  outdoor 
 antenna  is  not  practical  for  many  households,  particularly  those  located  in  apartment  buildings.  It  further  contends  that  even  households  with  outdoor  antennas  often  do  not  have  rotating  antennas  or  have  a 
 practical  means  of  re-  pointing  their  antennas  on  the  fly  to  achieve  optimum  reception  for  every  broadcast  station  in  the  market.  EchoStar  suggests  that  the  Commission  should  take  these  factors  into 
 account  and  recommend  modifications  to  the  signal  strength  standard. 


 36  Id.  at  15-  33. 
 37  Id.  at  34. 
 38  Id.  at  35. 
 39  MSTV  comments  at  2;  NAB  comments  at  16-  25;  Network  Affiliates  comments  at  13-  15  and  37-  38. 
 40  CEA  comments  at  3. 
 41  EchoStar  comments  at  4  and  6;  Robinson  Telephone  comments,  passim;  and  Viamorph,  Inc.  comments,  passim 
 (predictive  model  should  include  methods  to  account  for  variations  in  antenna  performance,  including  receiving  antenna  characteristics  and  detailed  geographical,  botanical,  atmospheric  and  other  data;  Viamorph  states  that  it  is 


 introducing  a  new  digital  smart  antenna  technology  into  the  consumer  marketplace). 
 42  EchoStar  comments  at  4  and  6. 
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 Federal  Communications  Commission  FCC  05-  199 
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 20.  In  the  subsections  below  we  examine  the  signal  strength  questions  addressed  in  the  SHVERA  and  other  planning  factor  issues  raised  in  the  Inquiry.  We  will  consider  the  comments  above  and  our 
 evaluations  of  the  issues  in  these  subsections  in  developing  our  recommendations  to  Congress  on  DTV  signal  strength  standards,  which  are  set  forth  at  the  end  of  this  section. 


 1.  Antenna  Gain,  Orientation,  and  Placement 
 21.  An  antenna  is  the  first  element  in  the  path  that  constitutes  a  households  TV  receiving  system.  The  antenna  receives  the  electromagnetic  energy  of  a  television  signal  and  converts  it  into  electrical 
 energy.  The  effectiveness  of  receiving  antennas  is  determined  both  by  factors  intrinsic  to  the  specific  antenna  design  and  by  external  factors.  With  regard  to  the  former,  antennas  are  designed  with  varying 
 amounts  of  antenna  gain  or  directivity.  The  greater  the  gain  of  a  receiving  antenna  is,  the  greater  the  antennas  ability  to  capture  weak  signals.  However,  there  is  a  significant  tradeoff  when  incorporating 
 additional  gain  in  an  antenna  design.  That  is,  designing  an  antenna  with  greater  gain  requires  that  it  also  be  designed  to  have  a  narrower  beamwidth.  Beamwidth,  in  turn,  refers  to  the  antennas  angle  of 
 orientation  within  which  the  gain  occurs.  The  narrower  the  beamwidth  of  a  receiving  antenna,  the  more  critical  it  is  to  accurately  aim  the  antenna  directly  at  the  source  of  the  signal  of  interest.  The  signal 
 strength  of  a  transmission  that  is  received  by  an  antennas  main  lobe  beamwidth  will  be  stronger  than  if  that  transmission  was  received  from  a  direction  outside  that  main  lobe.  With  regard  to  external  factors, 
 considerations  relating  to  antenna  placement  and  orientation  affect  the  ability  of  a  household  to  receive  an  adequate  DTV  signal.  For  example,  because  structures  located  within  the  line  of  sight  between  the 
 transmitter  and  the  receiving  antenna  can  block  or  weaken  the  strength  of  received  signals,  an  outdoor  antenna  installation,  such  as  upon  a  rooftop,  will  generally  allow  a  stronger  signal  to  be  received  by  the 
 antenna  than  will  an  indoor  antenna  installation.  Thus,  for  households  located  in  the  same  general  area,  an  indoor  antenna  will  generally  need  an  antenna  with  greater  gain  than  will  a  household  in  which  the 
 antenna  is  placed  outdoors.  If  an  antenna  is  oriented/  directed  so  that  its  maximum  gain  is  not  focused  on  the  desired  TV  signal,  the  received  energy  from  that  stations  signal  will  be  much  lower. 


 22.  Inherent  in  the  Commissions  definition  of  digital  television  service  area  are  certain  assumptions  regarding  the  receiving  antenna.  For  DTV,  the  Commission  assumes  that  the  receiving 
 antenna  is  located  outdoors  at  a  height  of  9  meters  above  ground.  43  In  addition,  the  Commissions  procedures  for  evaluating  DTV  service  areas  set  forth  specific  values  for  antenna  gain  that  depend  upon 
 the  specific  DTV  channel  band,  namely,  4  dB  for  low  VHF,  6  dB  for  high  VHF,  and  10  dB  for  UHF  and  assume  that  the  antenna  is  oriented  in  the  direction  which  maximizes  the  values  of  the  field  strength 
 received  for  the  signal  being  measured.  44 
 23.  In  the  Inquiry,  we  sought  comment  and  information  regarding  the  antenna  equipment  available  to  and  used  by  consumers  as  a  possible  factor  in  the  DTV  signal  availability  standards. 


 Consistent  with  the  provisions  of  Section  339(  c)(  1)(  B)(  i),  we  asked  whether  there  is  a  need  to  revise  the  standards  by  which  adequate  DTV  network  signals  are  deemed  available  to  households  in  order  to 
 account  for  the  facts  that  DTV  antennas  can  be  mounted  on  a  roof  or  within  a  home  and  can  be  installed  in  a  fixed  position  or  in  a  mounting  that  allows  them  to  be  rotated.  As  required  under  Section 
 339(  c)(  1)(  B)(  iii),  we  also  requested  comment  and  information  on  whether  a  standard  other  than  the  presence  of  a  signal  of  a  certain  strength  should  be  used  to  ensure  that  a  household  can  receive  a  high-quality 
 picture  using  antennas  of  reasonable  cost  and  installation.  Specifically,  we  asked  if  the  inherent  assumptions  regarding  DTV  antenna  receiving  systems  should  be  modified  or  extended  insofar  as  they 


 43  See  OET  Bulletin  69,  Longley-  Rice  Methodology  for  Evaluating  TV  Coverage  and  Interference  (February  6, 
 2004),  at  6  Table  4;  see  also  47  C.  F.  R.    73.  699. 
 44  Id.  at  9. 
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 Federal  Communications  Commission  FCC  05-  199 
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 relate  to  the  proper  determination  of  whether  households  are  unserved  by  adequate  broadcast  DTV  network  signals  and  are  thus  eligible  to  receive  distant  DTV  network  signals  from  a  satellite  service 
 provider.  We  requested  that  commenting  parties  provide  information  on  the  types  of  antennas  that  are  in  use  currently,  or  soon  to  be  available  for  outdoor  or  indoor  residential  use,  including  technical 
 specifications  (e.  g.,  size,  gain,  beamwidth)  and  how  those  factors  affect  cost  and  deployment.  Further,  we  requested  information  on  the  availability  and  cost  of  various  devices  that  can  be  used  to  aim  these 
 antennas  (e.  g.,  rotors)  toward  DTV  transmitters.  In  this  regard,  we  requested  comment  on  how  the  addition  of  a  rotor  would  affect  the  size  of  an  antenna  system  and  thus  the  ability  of  consumers  to  mount 
 an  antenna  indoors.  We  asked  that  commenting  parties  provide  an  evaluation  of  whether  the  use  of  an  indoor  antenna  with  or  without  a  rotor  would  provide  similar  performance  to  that  expected  based  on  the 
 Commissions  assumed  planning  factors. 
 24.  Inquiry  Record.  The  parties  commenting  in  the  Inquiry  who  represent  broadcast  and  consumer  electronics  interests  generally  state  that  the  Commission  should  continue  to  determine  whether 


 a  household  is  unserved  based  on  the  assumed  planning  factors,  including  the  use  of  an  outdoor  stationary  antenna  mounted  at  a  height  of  9  meters.  For  example,  the  NAB  states  that  broadcasters  have  built 
 transmission  systems  based  on  the  Commissions  standards  and  it  would  be  unfair  to  now  assume  that  viewers  will  use  indoor  antennas.  45  In  a  statement  attached  to  the  NABs  comments,  the  engineering  firm 
 of  Meintel,  Sgrignoli,  and  Wallace  (MSW)  argue  that  the  planning  factors  for  the  DTV  receive  antenna  setup  are  reasonable  based  on  moderately  priced  equipment  that  is  readily  available  to  consumers  in  the 
 marketplace.  46  The  Network  Affiliates  argue  that  it  would  be  inappropriate  to  penalize  local  TV  stations  for  consumers  who  are  only  willing  to  install  an  indoor  antenna  when  the  consumer  is  willing  to  take 
 additional,  necessary  steps  to  obtain  adequate  satellite  reception.  47  Thus,  in  the  Network  Affiliates  view,  there  is  no  basis  for  modifying  the  inherent  assumptions  regarding  DTV  antenna  receiving  systems  in  the 
 DTV  planning  factors.  48  EchoStar  and  Paul  Robinson,  the  General  Manager  of  Robinson  Telephone,  take  a  different  position,  arguing  that  the  antenna  planning  factors  should  be  revised  to  take  into  account 
 indoor  antennas,  with  EchoStar  adding  that  the  lack  of  rotation  capability  in  outdoor  antennas  should  also  be  considered.  49 


 25.  Looking  first  at  the  record  on  antenna  performance,  commenting  parties  representing  the  interests  of  broadcasters  and  the  consumer  electronics  industry  submit  that  reasonably  priced  antennas 
 that  exceed  the  gain  and  front-  to-  back  ratios  assumed  in  the  planning  factors  are  readily  available.  50  The  Network  Affiliates  argue  that  the  planning  factors  should  consider  the  TV  receiving  antenna  to  be  outside 
 on  the  roof  or  adjacent  to  the  house.  51  They  further  submit  that  the  antenna  should  be  considered  oriented  to  the  desired  signal,  and  if  the  desired  stations  are  not  located  in  the  same  direction,  then  the  antenna 
 should  be  considered  orientable  in  the  direction  of  the  desired  signal(  s).  52  The  Network  Affiliates  submit 
 45  NAB  comments  at  18-  19. 


 46  NAB  comments,  Attachment  1  (engineering  statement  of  MSW)  at  3. 
 47  Network  Affiliates  comments  at  34. 
 48  Id.  at  34-  35. 
 49  EchoStar  comments  at  6-  8;  Robinson  Telephone  comments,  passim. 
 50  Network  Affiliates  comments  at  29-  32;  NAB  comments  at  35-  43;  MSTV  comments,  Attachment  (Engineering 
 Statement  of  Louis  Robert  du  Treil,  Jr.  of  dLR  at  5-  6;  see  also  ATI  Technologies  comments,  passim. 
 51  Network  Affiliates  comments  at  34. 


 52  Id. 
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 Federal  Communications  Commission  FCC  05-  199 
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 that  the  equipment  for  a  high  quality  outdoor  antenna  receiving  system,  including  an  eight-  way  bowtie-with-  screen  antenna  and  a  rotor  with  remote  control  can  be  purchased  for  approximately  $100.  53 
 26.  Jules  Cohen,  in  an  engineering  appendix  to  the  Network  Affiliates  comments,  states  that  manufacturers  specified  antenna  gains  vary  from  averages  of  12  dB  or  more  for  UHF,  mostly  about  10 
 dB  for  high  VHF,  and  5-  7  dB  for  low  VHF.  54  The  NAB  and  the  Network  Affiliates  submit  that  the  best  UHF  antenna,  considering  both  performance  and  value,  is  an  eight-  bay  bowtie-  with-  screen  antenna.  55 
 The  Network  Affiliates  state  that  an  FCC  study  in  1980  determined  that  this  design  provides  an  average  gain  of  13.  4  dB.  56  They  also  state  that  antennas  with  higher  average  UHF  gains  are  available,  although 
 they  are  slightly  more  expensive.  57  The  consulting  engineering  firm  of  du  Treil,  Lundin  &  Rackley  (dLR)  (in  an  attachment  to  MSTVs  comments),  the  Network  Affiliates  and  Viamorph  each  compiled  data  from 
 several  leading  manufacturers  of  consumer  television  antennas.  58  Their  compilations  show,  in  part,  that  Channel  Master  offers  an  eight-  bay  bowtie-  with-  screen  UHF  antenna,  Model  No.  4228,  with  an  average 
 gain  of  12.0  dB;  Winegard  offers  a  UHF  antenna  designed  for  deep  fringe  areas,  Model  PR-  9032,  with  a  gain  of  15.6  dB;  and  Antennas  Direct  offers  a  long-  range  UHF  antenna,  Model  91XG,  with  a  gain  of  16.  7 
 dB.  59  The  Network  Affiliates  indicate  that  the  Channel  Master  4228  retails  for  $38.99  from  Solid  Signal  (solidsignal.  com);  Winegards  PR-  9032  retails  for  $34.99  from  Solid  Signal;  and  Antenna  Directs  Model 
 91XG  sells  for  $79  (antennasdirect.  com).  60  Based  on  this  information,  the  Network  Affiliates  submit  that  the  Commissions  DTV  planning  factor  of  10  dB  for  UHF  antenna  gain  is  very  conservative  and  can 
 easily  be  achieved  with  readily  available  consumer  antennas.  61 
 27.  The  Network  Affiliates  submit  that  the  most  recent  study  of  VHF  antennas  of  which  they  are  aware  was  conducted  by  the  Institute  for  Telecommunications  Sciences  (ITS),  an  agency  of  the 


 Department  of  Commerce,  in  1979.  That  study  indicated  that  the  average  gain  of  an  antenna  for  low  VHF  use  was  4.43  dB  and  for  high  VHF  band  use  was  8.43  dB.  The  Network  Affiliates  note  that  these  gain 
 values  exceed  the  DTV  planning  factor  gain  values  of  4  dB  and  6  dB,  respectively.  62  The  Network  Affiliates  also  state  that  currently  there  are  a  number  of  VHF  antennas  on  the  market  that  exceed  the  gain 
 assumed  in  the  DTV  planning  factors.  They  submit  that  these  include  the  Antennacraft  Model  CS  1100, 
 53  Id.  at  35. 


 54  Network  Affiliates  comments,  Appendix  (Engineering  Statement  of  Jules  Cohen)  at  2. 
 55  Network  Affiliates  comments  at  18  and  35;  NAB  comments  at  27-  28. 
 56  Network  Affiliates  comments  at  18.  The  Network  Affiliates  further  note  that  the  Electronics  Technicians 
 Association,  a  group  whose  members  install  and  work  in  the  field  with  antennas  on  a  day-  to-  day  basis,  stated  in  its  comments  in  the  Commissions  proceeding  in  CS  Docket  No.  98-  201  that  the  eight-  bay  and  four-  bay  bowtie-  with-screen 


 antennas  are  the  conventional  UHF  antennas  for  fringe  rural  areas.  Id.  (citing  CS  Docket  No.  98-  201,  Electronics  Technicians  Association,  International,  Inc.  (ETA)  Comments  at  23). 


 57  Id.  at  18-  19. 
 58  Id.  at  19;  see  also  MSTV  comments,  Attachment  (Engineering  Statement  of  dLR)  at  6  (Table  2);  Viamorph 
 comments  at  1-  2. 
 59  Network  Affiliates  comments  at  19. 


 60  Id.  at  19  n.  51. 
 61  Id.  at  19. 
 62  Id.  at  19-  20. 
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 16 
 with  an  average  gain  in  the  low  VHF  band  of  6.9  dB  and  an  average  gain  in  the  high  VHF  band  of  9.6  dB;  the  Channel  Master  Model  No.  3610,  with  an  average  gain  in  the  low  VHF  band  of  5.8  dB  and  an  average 
 gain  in  the  high  VHF  band  of  11.4  dB;  and  the  Winegard  Model  HD4053P,  with  a  gain  in  the  low  VHF  band  between  5.9  and  6.6  dB  and  in  the  high  VHF  band  of  between  9.6  and  11.4  dB.  63  The  Network 
 Affiliates  state  that  the  Antennacraft  CS  1100  has  a  list  price  of  $96.08  (antennacraft-  tpd.  com)  and  that  Winegards  HD4053P  retails  for  $119.99  from  Solid  Signal.  64  They  submit  that  with  antennas  offering 
 these  levels  of  performance,  it  is  apparent  that  the  DTV  planning  factors  of  4  dB  gain  for  low  VHF  signals  and  6  dB  for  high  VHF  signals  are  also  very  conservative  and  can  easily  be  achieved  with  readily 
 available  consumer  VHF  antennas.  The  NAB  submits  that  another  option  for  consumers  is  the  Winegard  SquareShooter  SS-  2000,  a  small,  attractive  directional  antenna  with  a  preamplifier.  65  The  NAB  states  that 
 while  the  manufacturer  states  that  the  antenna  alone  has  a  gain  of  4.5  dB  at  UHF  (below  the  planning  factor  assumption),  the  gain  of  combined  setup  with  the  preamplifier  far  exceeds  the  planning  factors.  It 
 submits  that  the  SquareShooter  2000  is  available  for  about  $98.99  from  Solid  Signal.  66 
 28.  The  Network  Affiliates  further  submit  that  although  combination  VHF/  UHF  antennas  do  not  generally  perform  as  well  as  separate  VHF  and  UHF  antennas,  there  are  consumer  models  available  that 


 exceed  the  assumed  gains  in  the  DTV  planning  factors.  For  example,  they  state  that  Winegards  Model  D7084P  has  gain  of  from  6.2  dB  to  7.6  dB  in  the  low  VHF  band,  from  10.8  dB  to  12.0  dB  in  the  high 
 VHF  band,  and  from  11.8  dB  to  14.6  dB  in  the  UHF  band  and  that  Antennacrafts  Model  HD1850  has  an  average  gain  of  6.2  dB  in  the  low  VHF  band,  10.7  dB  in  the  high  VHF  band,  and  10.0  dB  in  the  UHF 
 band.  67  The  Network  Affiliates  indicate  that  Winegards  HD7084  retails  for  $127.99  from  Solid  Signal  and  Antennacrafts  HD1850  has  a  list  price  of  174.97.  68  They  further  note  that  even  Channel  Masters 
 eight-  bay  bowtie-  with-  screen  UHF  antenna,  Model  No.  4228,  has  been  measured  by  an  independent  engineering  firm,  Dielectric  Communications,  to  possess  an  average  gain  of  approximately  3.0  dB  in  the 
 low  VHF  band,  approximately  9.  0  dB  in  the  high  VHF  band,  and  approximately  15.0  dB  in  the  UHF  band  (which  exceeds  the  manufacturers  own  specifications)  and  that  it  retails  for  $38.99  from  Solid  Signal.  69 


 29.  The  Network  Affiliates  state  that  such  high-  gain  antennas  are  not  appropriate  for  all  receiving  locations  and  that  where  signal  strength  is  already  adequate  or  nearly  adequate,  such  a  high-  gain  antenna 
 could  overload  a  receiver.  They  note  that  for  those  circumstances  antenna  manufacturers  produce  smaller  antennas  with  less  gain.  They  point  out  that  CEA,  in  conjunction  with  Decisionmark,  has  established  a 
 website,  AntennaWeb.  org,  that  is  designed  to  assist  consumers  in  selecting  an  appropriate  outdoor  receiving  antenna.  The  Network  Affiliates  submit  that  even  if  the  gain  of  an  antenna  is  less  than  the  gain 
 assumed  in  the  planning  factors,  that  does  not  mean  that  the  planning  factors  are  defective,  because  at  locations  where  those  antennas  are  appropriate  the  ambient  signal  strength  will  already  exceed  the 
 thresholds  set  forth  in  the  planning  factors.  70 


 63  Id.  at  20. 
 64  Id.  at  20  n.  53  (pricing  information  for  Channel  Master  No.  3610  not  available). 
 65  NAB  comments  at  22. 
 66  Id.  at  22  and  Attachment  1  (Engineering  Statement  of  MSW)  at  16. 
 67  Network  Affiliates  comments  at  20. 
 68  Id.  at  20,  n.  54. 
 69  Id.  at  20-  21  and  n.  55. 
 70  Id.  at  21. 
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 30.  The  Network  Affiliates  observe  that,  although  it  is  not  an  element  affecting  the  digital  signal  strength  standards,  the  Commission  did  assume  that  TV  receiving  antennas  would  have  a  directional  gain 
 pattern  in  order  to  discriminate  against  off-  axis  undesired  stations  and  thereby  ameliorate  interference.  71  They  note  that  the  ATSC  recommends  the  use  of  a  directional  gain  antenna  to  enhance  receiver 
 performance  with  respect  to  multipath:  [  A]  n  antenna  with  a  directional  pattern  that  gives  only  a  few  dB  reduction  in  a  specific  multipath  reflection  can  dramatically  improve  the  equalizers  performance.  Such 
 modest  directional  performance  can  be  achieved  with  antennas  of  consumer-  friendly  size,  especially  at  UHF.  72  The  DTV  planning  factors  account  for  this  directionalization  in  the  assumed  front-  to-  back  ratios 
 of  10  dB  for  low  VHF,  12  dB  for  high  VHF,  and  14  dB  for  UHF.  The  Network  Affiliates  indicate  that  it  is  common  for  readily  available  consumer  antennas  to  meet  or  exceed  these  assumed  front-  to-  back  ratios. 
 They  state  that,  of  the  antennas  mentioned  above,  the  front-  to-  back  ratio  of  Channel  Masters  eight-  bay  bowtie-  with-  screen  UHF  Model  No.  4228  exceeds  19  dB  at  all  UHF  frequencies  and  is  24  dB  at  channel 
 43.  Similarly,  the  front-  to-  back  ratio  of  Winegards  UHF  Model  PR-  9032  is  14  dB  at  Channel  14  and  20  dB  at  both  channel  32  and  channel  50.  The  Network  Affiliates  state  that  commonly  available  VHF 
 antennas  also  appear  to  easily  exceed  the  assumed  front-  to-  back  ratios  for  the  low  and  high  VHF  bands.  They  state  that  Antennacrafts  Model  CS  1100  has  a  front-  to-  back  ratio  of  19.4  dB  in  the  low  VHF  band 
 and  17.6  dB  in  the  high  VHF  band;  and  that  the  front-  to-  back  ratio  of  Winegards  VHF  Model  HD4053P  is  17  dB  or  greater  across  both  the  low  and  high  VHF  bands.  73 


 31.  The  Network  Affiliates  state  that  VHF/  UHF  combination  antennas  also  greatly  exceed  the  assumed  front-  to-  back  ratios  for  the  low  and  high  VHF  bands  and  meet  the  assumed  ratios  for  the  UHF 
 band.  They  indicate  that  the  front-  to-  back  ratio  of  Winegards  VHF/  UHF  combination  antenna  Model  HD7084P  is  20  dB  or  greater  in  the  low  VHF  band,  15  dB  or  greater  in  the  high  VHF  band,  and  is  11  dB 
 at  channel  14  and  20  dB  at  both  channel  32  and  channel  50.  They  state  that  the  front-  to-  back  ratio  of  Antennacrafts  VHF/  UHF  combination  antenna,  Model  HD1850,  is  20.2  dB  in  the  low  VHF  band,  17.3 
 dB  in  the  high  VHF  band,  and  13.7  dB  in  the  UHF  band.  74 
 32.  Jules  Cohen,  MSW,  the  NAB,  and  the  Network  Affiliates  submit  that  in  addition  to  selecting  antenna  with  performance  criteria  that  meet  their  needs,  consumers  can  be  expected  to  exert  the  same 


 efforts  to  receive  DTV  signals  that  they  have  always  been  expected  to  exert  to  receive  analog  signals.  They  state  that  this  may  include  the  use  of  a  rotor  to  properly  orient  the  antenna  to  receive  different 
 signals  if  needed  and,  in  fringe  areas  where  signal  strength  is  known  to  be  weak,  use  of  a  low-  noise  amplifier  (LNA)  or  pre-  amplifier.  75  Jules  Cohen,  dLR,  MSW,  and  the  Network  Affiliates  report  that 
 there  are  many  current  offerings  of  moderately  priced  LNAs  with  signal  amplification  available  in  values  between  18-  30  dB  and  with  noise  figure  values  between  3-  5  dB.  76  For  example,  they  observe  that 
 Winegard  currently  offers  16  different  LNAs  with  gains  ranging  from  17  dB  to  29  dB  and  note  that  the  Winegard  Model  AP-  8275  provides  an  average  gain  of  29  dB  for  VHF  and  28  dB  for  UHF  with  an 


 71  Id.  at  21-  22. 
 72  Id.  at  22  (quoting  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  Doc  A/  74  (June  18,  2004) 
 at  24). 
 73  Id.  at  22-  23. 


 74  Id.  at  23. 
 75  Id.  at  23-  24;  NAB  comments  at  16-  23. 
 76  NAB  comments,  Attachment  1  (Engineering  Statement  of  MSW)  at  17-  18;  see  also  Network  Affiliates 
 comments  at  25-  26  and  Appendix  (Engineering  Statement  of  Jules  Cohen)  at  3. 
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 internal  noise  figure  of  only  2.9  dB  and  2.8  dB  in  those  respective  bands,  with  a  retail  price  of  $77.99  from  Solid  Signal.  77  Similarly,  the  Channel  Master  7777  has  an  average  gain  of  23  dB  for  VHF  and  26 
 dB  for  UHF  with  internal  noise  figures  of  2.8  VHF  and  2.0  dB  for  those  respective  bands,  and  it  retails  for  $56.99  from  Solid  Signal.  78  Also,  Antennacraft  offers  an  LNA  with  adjustable  gain  to  prevent  overload, 
 Model  10G212,  that  provides  an  average  gain  of  30  dB  for  both  VHF  and  UHF  with  a  noise  figure  of  less  than  4.0  dB  for  VHF  and  less  than  3.5  dB  for  UHF,  with  a  list  price  of  $33.63.  79  The  Network  Affiliates 
 identify  Blonder  Tongue  and  Advanced  Receiver  Research  as  additional  LNA  manufacturers.  MSW  submits  that  the  ready  availability  of  these  preamplifiers  provides  a  substantial  cushion  against  the 
 possibility  of  any  losses  not  specifically  accounted  for  in  the  planning  factors.  80  Jules  Cohen  states  that  a  conservative  choice  of  parameters  to  illustrate  the  advantage  of  using  a  pre-  amplifier  at  the  antenna  would 
 be:  amplifier  noise  figure  5  dB,  amplifier  gain  20  dB  and  receiver  noise  figure  of  12  dB.  81  He  further  states  that  the  resulting  system  noise  figure  would  be  5.2  dB,  which  considering  that  the  system  noise 
 figures  in  the  planning  factors  are  10  dB  for  VHF  and  7  dB  for  UHF,  would  provide  an  extra  margin  to  minimize  the  impact  of  system  mismatches.  82 


 33.  With  regard  to  proper  orientation  of  antennas,  EchoStar  contends  that  even  households  with  outdoor  antennas  often  do  not  have  rotating  antennas  or  have  a  practicable  means  of  re-  pointing  their 
 antennas  on  the  fly  to  achieve  optimum  reception  for  every  broadcast  station  in  the  market.  83  It  states  that  in  some  markets  not  all  of  the  network  stations  may  be  transmitting  from  the  same  site,  so  that  there 
 may  be  no  single  optimal  pointing  solution.  EchoStar  further  contends  that  even  households  with  antennas  that  are  capable  of  rotating  generally  do  not  have  the  ability  to  adjust  the  orientation  of  their 
 antennas  on  the  fly  so  that  for  most  purposes  the  antenna  is  non-  rotating.  In  a  statement  appended  to  EchoStars  comments,  the  consulting  engineering  firm  of  Hammett  &  Edison,  Inc.  (H&  E)  claims  a  worst 
 case  loss  scenario  of  14  dB  for  a  high-  performance  (i.  e.,  high-  gain)  antenna  at  UHF.  84  H&  E  further  states  that  it  conducted  a  study  using  the  Terrain  Integrated  Rough-  Earth  Model  (TIREM)  that  found  that  the 
 majority  of  all  households  in  the  United  States  are  able  to  receive  at  least  two  analog  TV  stations  of  Grade  B  intensity  and  that,  of  those  households,  the  majority  receive  at  least  one  from  an  angle  that  differs  by 
 greater  than  25  o  from  another  station.  85  As  a  result,  it  contends  that  almost  all  households  will  have  impaired  reception  of  at  least  one  station.  EchoStar  believes  that  this  analysis  suggests  that  signal 
 strength  loss  from  the  lack  of  a  rotating  antenna  can  be  significant  and  should  therefore  be  taken  into  account.  86  It  states  that  one  way  to  do  so  would  be  to  conduct  further  study  to  determine  the  average 


 77  Network  Affiliates  comments  at  25  and  n.  70. 
 78  Id.  at  25  and  n.  71. 
 79  Id.  at  25-  26. 
 80  NAB  comments  at  23,  and  Attachment  1  (Engineering  Statement  of  MSW)  at  18. 
 81  Network  Affiliates  comments,  Appendix  (Engineering  Statement  of  Jules  Cohen)  at  3. 
 82  Id. 
 83  EchoStar  comments  at  7-  8. 
 84  Id.,  Attachment  A  (Engineering  Statement  of  H&  E)  at  3  (worst  case  scenarios  are  10,  12  and  14  dB  for  low 
 VHF,  high  VHF  and  UHF,  respectively).  H&  E  does  not  provide  a  value  for  average  signal  loss  from  mispointing, 
 85  Id. 


 86  EchoStar  comments  at  7-  8. 
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 signal  loss  caused  by  the  lack  of  a  rotating  antenna  and  to  subtract  that  amount  from  the  measured  signal  strength  before  comparing  it  to  the  Commissions  signal  strength  standards. 
 34.  On  the  other  hand,  dLR,  the  Network  Affiliates,  and  the  NAB  argue  that  the  Commission  should  continue  to  assume  that  DTV  antennas  are  oriented  towards  the  desired  signal,  and  if  the  desired 
 stations  are  not  located  in  the  same  direction,  that  that  antenna  will  be  orientable  in  the  direction  of  the  desired  signal.  87  They  argue  that  this  assumption  remains  appropriate  given  the  availability  of  reasonably 
 priced  antennas  and  rotors  as  described  above.  The  Network  Affiliates  submit  that  the  Electronics  Technicians  Association  (ETA)  showed  in  the  Commissions  proceeding  in  CS  Docket  No.  98-  201  that 
 the  majority  of  home  antenna  systems  in  Putnam  County,  Indiana,  a  location  representative  of  the  outer  reaches  of  the  service  areas  of  several  broadcast  stations,  contain  a  rotor  (in  addition  to  a  LNA)  and  that 
 this  is  true  even  though  homeowners  in  Putnam  County  can  receive  network  programming  from  each  of  the  four  major  networks  from  stations  all  located  in  Indianapolis.  88  They  argue  that  consumers  can  and 
 will  obtain  rotors  when  they  believe  that  they  need  them.  They  note  statements  by  the  ETA  that  rotors  are  economical  ($  60-$  75)  and  do  not  require  constant  rotation  and  that  to  circumvent  the  intent  of  the  SHVA 
 because  the  homeowner  prefers  not  to  invest  in  a  rotor  where  needed  is  not  right.  89  The  NAB  argues  that  it  would  be  discriminatory  to  assume  that  a  DBS  households  over-  the-  air  antenna  is  improperly  oriented 
 when  that  same  households  satellite  antenna  must  be  precisely  oriented  towards  the  satellite  to  get  any  service  at  all.  90  It  notes  that  the  DTV  transition  has  been  premised  on  the  assumption  that  viewers  will 
 use  properly  oriented  antennas  to  receive  digital  TV  signals.  91 
 35.  The  NAB  states  that,  in  most  instances  consumers  can  use  a  single,  fixed  antenna,  because  the  TV  transmitters  in  many  markets  are  co-  located.  In  such  cases,  there  will  be  no  need  for  a  rotor.  It 


 states  that  in  markets  where  TV  towers  are  located  at  different  sites,  local  electronics  installers  sometimes  offer  a  special  antenna  designed  to  receive  signals  from  two  different  directions,  again  without  the  need 
 for  a  rotor.  And  NAB  states  that  for  those  instances  which  differ  from  the  situations  just  discussed,  consumers  can  acquire,  at  a  modest  cost,  a  rotor  that  enables  a  rooftop  antenna  to  be  oriented  to  achieve 
 the  best  signal  from  a  particular  station.  92 
 36.  With  regard  to  the  availability  of  antenna  rotors,  the  engineering  statements  and  comments  submitted  by  dLR  and  the  Network  Affiliates  point  out  that  many  models,  such  as  those  sold  by  Channel 


 Master,  Antennacraft,  Delhi  (formerly  Jerrold),  and  Radio  Shack,  are  readily  available.  The  comments  also  indicate  that  some  of  these  rotors  are  available  with  a  remote  control  so  that  the  viewer  can  properly 
 orient  the  antenna  conveniently,  from  the  couch  or  other  location.  93  The  NAB  and  the  Network  Affiliates  submit  that  prices  for  rotors  range  from  $68.99  for  a  Channel  Master  unit  with  remote  control  (CM 
 9521A,  available  from  Solid  Signal)  to  $94.88  for  an  Antennacraft  model  (available  at  antennacraft- 
 87  MSTV  comments  at  2  and  Attachment  (Engineering  Statement  of  dLR)  at  9;  Network  Affiliates  comments  at 
 34-  35;  NAB  comments  at  19-  20  and  Att.  1  (Engineering  Statement  of  MSW)  at  13-  15. 
 88  Network  Affiliates  comments  at  27. 


 89  Id.  (quoting  CS  Docket  No.  98-  201,  ETA  Comments,  supra  note  56,  at  6). 
 90  NAB  comments  at  19-  20. 
 91  See  NAB  comments  at  25-  26. 
 92  Id.  at  20. 
 93  MSTV  comments,  Attachment  (Engineering  Statement  of  dLR)  at  9;  Network  Affiliates  comments  at  27  and 
 Appendix  (Engineering  Statement  of  Jules  Cohen),  Exhibit  3  (Rotors). 
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 Federal  Communications  Commission  FCC  05-  199 
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 tpd.  com).  94  Viamorph,  a  manufacturer  and  licensor  of  antenna  technologies,  states  that  its  research  indicates  that  aiming  a  directional  antenna  is  more  difficult  for  digital  TV  signals  than  for  analog  TV 
 signals  and  that  a  fixed  digital  TV  antenna  may  not  be  a  viable  solution  for  many  consumers.  95  Viamorph  submits  that  it  is  introducing  a  new  class  of  antennas  which  it  calls  DiSA  (Digital  Smart  Antenna)  that 
 automatically  adjust  their  electrical  shapes  in  response  to  changes  in  environment  and  signal  conditions  so  as  to  maintain  optimal  performance.  We  also  observe  that  CEA  has  issued  a  voluntary  industry  standard 
 (CE-  909)  for  TV  antennas  that  automatically  adjust  their  receive  pattern  to  increase  their  gain  in  specific  directions  to  receive  individual  signals.  We  have  examined  an  antenna  system  constructed  to  this 
 standard,  the  DTA  5000  (manufactured  by  DX  Antenna  Co.)  which  was  small  enough  to  be  used  indoors  as  well  as  outdoors,  and  have  observed  that  it  does  appear  to  provide  significantly  improved  reception  of 
 individual  digital  TV  signals. 
 37.  With  regard  to  indoor  antennas,  EchoStar  states  that,  because  structures  located  within  the  line  of  sight  between  a  TV  transmitter  and  receiving  antenna  can  block  or  weaken  the  strength  of  received 


 signals,  an  outdoor  antenna  will  generally  allow  a  stronger  signal  to  be  received  than  will  an  indoor  antenna.  96  It  argues  that  households  in  which  the  antenna  is  placed  indoors  will  generally  need  an  antenna 
 with  greater  gain  than  will  a  household  in  which  the  antenna  is  placed  outdoors.  EchoStar  argues,  however,  that  because  of  limitations  on  the  physical  dimensions  of  indoor  antennas,  they  have  always  had 
 less  gain  than  typical  outdoor  antennas.  EchoStar  notes  that  a  review  by  H&  E  of  the  existing  literature  published  as  recently  as  2005  and  as  far  back  as  1959  shows  that  indoor  antenna  gain  is  consistently  about 
 9  dB  or  more  below  the  values  for  outdoor  antennas.  97  EchoStar  also  submits  that  signal  loss  due  to  building  penetration  before  it  reaches  an  indoor  antenna  can  be  as  great  as  30  dB  for  VHF  signals  in  a 
 highly  populated  area  like  New  York  City,  but  this  will  vary  depending  on  which  floor  of  a  building  the  indoor  antenna  is  located.  98  EchoStar  argues  that  these  factors  mean  that  households  relying  on  an  indoor 
 antenna  for  DTV  reception  are  at  a  considerable  disadvantage.  It  further  argues  that  an  outdoor  antenna  is  not  practical  for  many  households,  particularly  those  located  in  apartment  buildings  and  that  for  these 
 reasons  the  DTV  signal  strength  standards  should  take  into  account  indoor  antenna  use.  99  Paul  Robinson  similarly  argues  that  in  a  dense  urban  area  most  people  may  be  living  in  multi-  story  apartment  buildings 


 94  NAB  comments  at  20;  Network  Affiliates  comments  at  27-  28. 
 95  Viamorph  comments  at  2-  4.  Viamorph  indicates  that  its  DiSA  TM  antenna  is  amenable  to  indoor  and  outdoor 
 mounting,  with  the  current  standard  model  consisting  of  a  flat,  rectangular  package  about  60  cm  by  40  cm  (approximately  23  inches  by  16  inches)  on  a  side  and  less  than  two  inches  (i.  e.,  about  5  cm)  thick. 


 96  EchoStar  comments  at  6.  EchoStar  (Comments,  Attachment  A  (Engineering  Statement  of  H&  E)  at  4  and  14-  15) 
 points  to  a  study  published  by  the  Institute  for  Telecommunication  Sciences  in  1979  (FizGerrel,  R.  G..  et  al.,  Television  Receiving  Antenna  System  Component  Measurements,  NTIA  Report  79-  22,  June  1979)  and  to  more 


 recent  data  published  by  Dielectric  Communications  (Kerry  W.  Cozad,  Measured  Performance  Parameters  for  Receive  Antennas  Used  in  DTV  Reception,  Proceedings  of  the  NAB  Engineering  Conference,  2005  (Cozad 
 Study)). 
 97  EchoStar  comments  at  6-  7.  H&  E  indicates  that  studies  show  that  indoor  antennas  typically  provide  about  8  dB, 
 10  dB,  and  9  dB  less  gain  than  outdoor  antennas  in  the  low  VHF,  high  VHF,  and  UHF  bands,  respectively.  EchoStar  comments,  Att.  A  (Engineering  Statement  of  H&  E)  at  4. 


 98  EchoStar  comments  at  7. 
 99  EchoStar  comments  at  6-  7. 
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 or  in  condominium  complexes  and  may  be  unable  to  install  an  external  antenna.  100  He  urges  that  the  planning  factors  should  take  these  situations  into  account. 
 38.  The  NAB  agrees  that  indoor  antennas  provide  inferior  reception  capability  to  outdoor  antennas.  101  In  this  regard,  it  observes  that  indoor  antennas  are  often  non-  directional  and  more  prone  to 
 interference  due  to  being  mounted  at  lower  heights  and  behind  wall(  s)  thus  reducing  the  ambient  field  strength  available  to  the  antenna.  102  NAB  also  states  that  indoor  antennas  are  usually  nondirectional  and 
 therefore  more  prone  to  problems  from  both  multipath  and  interference  and  are  more  easily  affected  by  the  proximity  to  viewers  whose  movement  may  contribute  to  altering  its  reception  characteristics.  103  The 
 NAB  and  MSW  further  state  that  it  is  because  rooftop  antennas  are  so  much  better  than  indoor  antennas  that  households  have  long  used  rooftop  antennas  to  achieve  reliable  over-  the-  air  reception,  particularly 
 where  the  households  are  at  some  distance  from  the  TV  transmitting  tower.  104  The  NAB  stresses  that  rural  households  often  rely  on  small  towers  -  with  over-  the-  air  antennas  considerably  higher  than  rooftop 
 level  -  to  receive  a  strong  signal  from  stations  several  dozen  miles  away.  This  is  in  contrast  to  the  case  of  indoor  antennas,  for  which  the  NAB  indicates  that  recent  tests  by  Kerry  W.  Cozad  show  that  some 
 currently  available  indoor  antennas  deliver  a  weaker  signal  than  a  reference  dipole  antenna  (i.  e.,  these  antennas  actually  have  negative  gain).  105  The  Network  Affiliates  point  out,  however,  that  some  indoor 
 antennas  currently  available  have  an  average  gain  of  approximately  4  dB  and,  note  that  the  Silver  Sensor,  with  its  short  connection  wire,  does  not  have  the  line  loss  assumed  in  the  planning  factors.  106 


 39.  Contrary  to  EchoStar,  the  NAB  and  the  Network  Affiliates  argue  that  indoor  antennas  should  not  be  considered  in  the  DTV  signal  strength  standards.  107  They  submit  that  it  would  be  unfair  to 
 broadcasters  to  assume  that  viewers  will  use  only  indoor  (or  low-  quality  outdoor)  antennas  in  determining  whether  DBS  subscribers  are  eligible  to  receive  retransmitted  digital  network  signals.  The  NAB  states 
 that  it  is  specifically  because  indoor  antennas  perform  so  poorly  that  they  should  not  be  considered  for  defining  DTV  service.  108  It  further  states  that  introducing  an  assumption  that  consumers  would  use 
 indoor  antennas  would  be  contrary  to  one  of  the  most  fundamental  assumptions  of  the  Commission's  entire  DTV  planning  process,  leaving  broadcasters  in  the  position  of  having  built  a  system  to  Commission 
 specifications  that  the  Commission  would  not  deem  as  adequate  because  it  is  not  designed  to  provide  service  to  indoor  antennas.  109  The  NAB  and  MSW  also  state  that,  had  the  Commission  assumed  use  of 
 indoor  antennas  in  the  planning  the  digital  TV  transition,  that  process  would  have  been  radically  different,  with  stations  needing  enormously  higher  power  levels  to  reach  indoor  antennas  50  to  60  miles  away.  110 


 100  Robinson  Telephone  Company  comments  at  2. 
 101  NAB  comments  at  16-  17. 
 102  Id.  at  17. 
 103  Id. 
 104  Id.  at  17  and  Att.  1  (Engineering  Statement  of  MSW)  at  11-  12. 
 105  Id.  at  17  and  Att.  1  (Engineering  Statement  of  MSW)  at  11;  see  also  id.  at  Att.  2  (Cozad  Study,  supra  note  96)). 
 106  Network  Affiliates  reply  comments  at  6. 
 107  Id,  at  16-  19;  Network  Affiliates  comments  at  34,  39-  40. 
 108  NAB  reply  comments  at  3-  4  and  Att.  (Reply  Engineering  Statement  of  MSW)  at  5-  6. 
 109  Id.  at  4. 
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 They  add  that  such  higher  power  levels  would  have  changed  the  interference  calculations.  The  Network  Affiliates  similarly  argue  that  it  is  critical  to  the  Commissions  plan  to  replicate  analog  TV  service  areas 
 to  presume  that  households  will  exert  similar  efforts  to  receive  DTV  signals  as  they  have  always  been  expected  to  do  to  receive  analog  TV  signals.  111 


 40.  Evaluation.  After  considering  the  above  information,  in  response  to  Section  339(  c)(  1)(  B)(  iii)  we  conclude  that  the  current  DTV  planning  factor  assumptions  for  antenna  gain,  orientation,  and 
 placement  remain  appropriate  and  should  not  be  altered  for  the  reasons  discussed  below.  Following  from  that  conclusion,  we  also  find  that  the  current  signal  strength  standard  for  determining  whether  a  household 
 can  receive  a  high-  quality  picture  using  antennas  of  reasonable  cost  and  ease  of  installation  remains  satisfactory  and  that  a  different  standard  is  not  needed.  With  respect  to  Section  339(  c)(  1)(  B)(  i),  we  also 
 specifically  conclude  that  the  digital  television  signal  strength  standards  in  the  Commissions  rules  should  not  be  modified  to  account  for  the  fact  that  an  antenna  can  be  mounted  on  a  roof  or  placed  within  a  home 
 and  can  be  fixed  or  capable  of  rotating. 
 41.  The  record  on  the  performance  capabilities  and  availability  of  antenna  receiving  equipment  indicates  that  there  are  a  very  large  number  of  options  for  antennas  that  meet  or  exceed  the  gain  and  front-to- 


 back  ratio  capabilities  assumed  in  the  planning  factors.  In  particular,  we  observe  that  antennas  that  provide  gain  of  7  dB,  11  dB,  and  14  dB  or  more  and  front-  to-  back  ratios  of  19  dB,  17  dB,  and  20  dB  in 
 the  low  VHF,  high  VHF,  and  UHF  bands  respectively  are  readily  available  in  a  variety  of  models  and  at  a  range  of  affordable  prices,  i.  e.,  from  about  $35  to  about  $100.  These  capabilities  compare  favorably  to 
 the  respective  planning  factors  gain  values  of  4  dB,  6  dB,  and  10  dB  and  front-  to-  back  ratios  of  10  dB,  12  dB,  and  14  dB  by  a  fair  margin  (these  performance  levels  exceed  the  gain  standards  by  3  dB,  5  dB,  and  4 
 dB  and  the  front-  to-  back  ratio  standards  by  9  dB,  5  dB,  and  6  dB,  respectively).  In  cases  where  additional  margin  in  the  received  signal-  to-  noise  ratio  is  needed,  there  are  numerous  models  of  low-  noise  amplifiers 
 available.  Similarly,  we  observe  that  there  is  a  wide  variety  of  models  of  antenna  rotor  devices  available,  including  units  with  remote  controls,  at  reasonable  prices.  As  the  Network  Affiliates  point  out,  the 
 Commission  has  long  recommended  that  households  in  outlying  or  difficult  reception  areas  use  equipment  and  mounting  locations  appropriate  to  their  needs.  This  equipment  can  include  separate  UHF 
 and  VHF  antennas,  which  generally  provide  better  performance  than  a  combination  UHF/  VHF  antenna  at  little  or  no  additional  cost.  Our  own  review  of  the  websites  of  various  TV  receive  system  retailers  also 
 indicates  that  products  with  lower  performance  levels  and  prices  that  can  meet  many  households  digital  TV  receive  system  needs  are  readily  available.  Thus,  it  is  clear  that  the  availability  of  digital  TV  receive 
 systems  that  meet  or  exceed  the  antenna  performance  planning  factors  is  not  a  constraint  on  viewers  ability  to  receive  signals  under  the  current  noise-  limited  DTV  field  strength  signal  intensity  standards. 
 The  parties  commenting  in  our  Inquiry  did  not  specifically  address  the  issue  of  ease  of  antenna  installation.  However,  based  on  the  experience  of  the  Commission  and  its  staff  over  many  years  we  do 
 not  believe  that  ease  of  installation  is  generally  a  concern  for  households  in  installing  the  types  of  antenna  needed  for  use  with  over-  the-  air  DTV  service.  Those  antennas  are  essentially  of  the  same  design  and 
 mounting  configuration  as  those  that  have  been  used  for  analog  TV  service  (antenna  design  depends  on  the  desired  frequency,  gain,  and  front-  to-  back  ratio  characteristics,  but  not  on  the  modulation  type,  e.  g., 
 analog  or  digital,  of  the  signals  to  be  received).  TV  antennas  can  in  almost  all  cases  be  installed  by  a  household  resident  or,  if  the  resident  desires,  a  professional  installer  for  a  modest  charge. 


 42.  We  recognize  that  in  some  situations  the  transmitters  of  digital  TV  signals  that  households  may  desire  to  view  are  located  in  directions  that  vary  by  more  than  the  25  o  of  main  beam  reception 
 capability  provided  by  typical  TV  antennas.  In  such  cases  the  households  need  either  a  multiple  direction 
 110  Id.  at  18-  19  and  Att.  1  (Engineering  Statement  of  MSW)  at  3-  4. 


 111  Network  Affiliates  comments  at  v,  13-  15. 
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 antenna  system  or  an  antenna  with  a  rotor  that  allows  the  single  antenna  to  be  re-  oriented  in  the  direction  of  the  desired  signal.  We  find  that  the  signal  strength  standards  do  not  need  to  be  modified  to  account  for 
 situations  where  households  need  to  be  able  to  receive  signals  from  multiple  directions.  We  agree  with  dLR,  the  Network  Affiliates,  and  the  NAB  that  the  digital  TV  planning  model  should  continue  to  assume 
 that  a)  digital  TV  antennas  are  oriented  towards  the  desired  station  and  b)  if  the  stations  that  a  household  desires  to  view  are  not  all  located  in  the  same  direction,  then  the  household  employ  an  antenna  that  can  be 
 re-  oriented  in  the  proper  direction  to  receive  any  such  desired  station  at  any  given  time.  As  supported  by  the  pattern  of  antenna  rotor  use  in  Putnam  County,  Indiana  that  is  described  in  the  record  of  our  Inquiry, 
 we  conclude  that  consumers  will  obtain  and  use  rotors  if  they  need  them.  Likewise,  in  the  many  instances  where  households  view  signals  radiating  from  one  particular  direction  only,  we  conclude  that  those 
 households  would  not  need  a  rotor  and  therefore  would  not  install  one.  We  recognize  EchoStars  point  that  a  large  number  of  households  might  be  able  to  better  receive  signals  from  stations  transmitting  from 
 different  directions,  often  from  neighboring  markets,  if  they  used  a  rotor.  We  believe,  however,  that  it  is  best  left  to  individual  households  to  determine  whether  signals  emanating  from  different  directions  are 
 sufficiently  desirable  to  view  and,  thus,  whether  to  install  a  rotor  to  enable  their  reception.  In  any  case,  where  a  rotor  could  assist  in  the  reception  of  television  signals  for  whatever  reason,  consumers  are  able 
 now  to  obtain  them  readily  at  affordable  prices.  We  also  conclude  that  it  would  unnecessarily  penalize  broadcasters  and  distort  the  digital  TV  service  planning  model  to  reduce  the  assumed  available  DTV  field 
 strength  by  some  factor  based  on  a  households  use  of  a  rotor  as  suggested  by  EchoStar.  We  do  not  recommend  such  action. 


 43.  We  also  find  that  it  would  not  be  appropriate  to  account  for  the  use  of  indoor  antennas  in  the  DTV  field  strength  signal  standards  for  purposes  of  determining  eligibility  for  reception  of  distant 
 network  signals.  As  observed  by  the  commenting  parties,  the  strength  of  signals  available  for  indoor  reception  is  lower  due  to  signal  attenuation  caused  by  walls  and  other  structural  features  and,  in  most 
 cases,  lower  antenna  height  available  indoors.  The  amount  of  signal  attenuation  indoors  will  depend  on  the  material  used  in  a  buildings  construction  and  where  the  antenna  is  located  within  the  building.  In 
 addition,  the  smaller  antenna  designs  that  are  suitable  for  indoor  use  provide  less  gain  than  their  outdoor  counterparts.  The  differences  in  the  indoor  and  outdoor  reception  conditions  mean  that  service  will  be 
 receivable  in  many  areas  with  an  outdoor  antenna  but  not  with  an  indoor  antenna.  We  believe  that  it  would  be  impractical  to  attempt  to  account  for  indoor  reception  conditions  in  the  DTV  planning  factors. 
 As  NAB  and  MSW  observe,  the  technical  standards  for  the  digital  television  service  were  established  assuming  use  of  outdoor  antennas  at  9  meters/  30  feet  height  above  ground  and  with  the  gain  set  forth  in 
 the  planning  factors.  If  DTV  service  were  instead  based  on  consideration  of  indoor  reception,  then  the  power  levels  needed  to  replicate  stations  analog  service  at  distances  of  55-  60  miles  or  greater  would  be 
 substantially  higher.  For  example,  if  the  antenna  difference  were  assumed  to  be  -9  dB,  as  suggested  by  EchoStar  and  H&  E,  for  indoor  antennas  and  building  penetration  loss  were  assumed  to  be  a  conservative 
 21  dB,  then  stations  would  need  to  transmit  signals  with  an  additional  30  dB  of  power,  or  1000  times  the  power  now  authorized  for  DTV  stations.  112  Such  power  levels  are  not  practical  as  they  would  greatly 
 increase  the  potential  for  interference  between  stations  and  pose  power  costs  for  stations  that  would  likely  be  so  high  as  to  threaten  the  economic  viability  of  many  stations.  In  addition,  as  discussed  more  fully 
 below  in  the  section  on  the  digital  television  measurement  procedure,  it  is  not  practical  or  reasonable  to  specify  an  indoor  reception  situation  as  the  signal  level  that  is  available  indoors  will  vary  significantly  at 
 different  locations  within  a  residence.  For  example,  the  signal  level  available  near  an  unobstructed  window  is  likely  to  be  higher  than  that  which  is  available  in  a  basement  or  an  interior  room  with  masonry 
 walls. 


 112  A  30  dB  power  increase  would  mean  that  a  station  operating  at  1  MW  DTV  power  would  need  to  operate  with 
 1000  MW,  an  enormously  high  power  level  that  is  not  achievable  by  currently  available  TV  transmitters. 
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 44.  We  therefore  believe  that  the  current  DTV  service  and  operating  model  that  allows  stations  to  replicate  their  analog  service  areas  based  on  similar  assumptions,  i.  e.,  service  to  outdoor  antennas  at  9 
 meters,  remains  the  most  appropriate  plan  for  this  service.  As  with  analog  TV,  digital  TV  signals  are  receivable  at  many  locations  with  an  indoor  antenna.  As  the  distance  between  the  DTV  transmitter  and 
 receive  locations  increases,  the  received  signal  strength  decreases  and  the  opportunities  for  indoor  reception  decrease  in  the  same  manner  as  for  analog  service.  We  also  believe  that  it  would  be 
 impracticable  to  establish  a  regime  whereby  households  with  indoor  antennas  are  subject  to  different  signal  strength  standards  than  those  with  outdoor  antennas.  The  difficulty  would  arise  in  setting  and 
 applying  standards  for  situations  in  which  a  household  could  not  use  an  outdoor  antenna. 
 45.  We  recognize  that  there  are  instances  such  as  those  in  which  households  are  located  in  apartment  buildings  and  condominium  complexes  where  viewers  may  be  unable  to  use  an  outdoor 


 antenna.  However,  we  find  that  commenting  parties  representing  broadcast  interests  make  a  compelling  point  in  their  observation  that  satellite  dishes  likewise  can  not  provide  service  indoors  to  such  households. 
 We  anticipate  that  if  a  household  were  able  to  install  a  satellite  dish  outdoors,  it  could,  in  some  instances,  co-  locate  an  effective  broadcast  receive  antenna  with  that  dish. 


 2.  Receiver  Performance 
 46.  At  the  other  end  of  a  households  TV  receiving  system  path  is  the  television  receiver.  This  device  receives  the  broadband  electric  energy  that  is  taken  from  the  air  by  the  antenna  and  conveyed  to  it 
 by  the  downlead  connecting  wire,  selects  the  channel  desired  by  the  viewer,  and  processes  the  information  on  that  channel  to  provide  digital  television  and  other  services  to  the  consumer.  The  desired 
 channel  is  selected  by  the  receivers  tuner  section  and  then  demodulated  to  produce  the  19.4  mbps  ATSC  digital  bitstream  that  carries  the  program  and  other  information  provided  on  the  signal  by  the  broadcast 
 TV  station.  The  performance  of  a  digital  television  receiver  with  respect  to  reception  of  service  for  purposes  of  SHVERA  eligibility  determinations  depends  on  its  noise  figure,  signal-  to-  noise  (S/  N)  ratio, 
 and  adaptive  equalizer  capabilities.  113  Noise  figure  is  a  measure  of  the  level  of  noise  generated  internally  within  the  device.  114  Signal-  to-  noise  ratio  is  a  measure  of  the  receivers  ability  to  discern  a  desired  digital 
 television  signal  from  other  energy  (noise)  that  is  present  in  the  signals  channel.  The  adaptive  equalizer  is  a  feature  of  a  digital  television  receivers  tuner  section  that  determines  its  ability  to  handle  reflections 
 of  the  desired  signal.  These  reflections  are  also  known  as  multipath  signals  and  can  be  observed  on  analog  television  pictures  as  ghosts.  115  The  noise  figure  and  S/  N  measures  are  included  in  the  DTV 
 planning  factors  as  indicated  above.  The  planning  factors  assume  use  of  a  receiver  that  has  noise  figure  levels  of  not  more  than  10  dB  in  the  low  and  high  VHF  bands  and  7  dB  in  the  UHF  band  and  that  can 
 provide  service  when  the  received  S/  N  ratio  is  15  dB  or  more.  If  the  representative  values  of  actual  receiver  noise  figures  and  S/  N  ratios  are  different  from  those  of  the  planning  factors  it  could  affect  the 
 minimum  field  strength  needed  for  service.  If  the  sum  of  these  factors  is  greater  or  lower  than  that  assumed  in  the  planning  factors,  a  higher  field  or  lower  field  strength,  respectively,  would  be  needed  for 
 service.  Adaptive  equalizer  performance  is  not  included  in  the  planning  factors  because  it  was  assumed  that  the  receiver  designs  for  this  feature  would  adequately  handle  multipath  signals.  However,  adaptive 
 equalizer  performance  did  become  of  concern  more  recently  when  it  was  determined  that  multipath  was  a 
 113  There  are  other  receiver  performance  factors  such  as  selectivity,  overload,  and  shielding  against  signal  ingress 
 that  affect  its  ability  to  reject  unwanted  signals.  These  factors  are  less  important  in  the  context  of  this  Report. 
 114  All  electronic  devices  generate  some  amount  of  internal  noise,  the  level  of  which  depends  on  their  design  and 
 the  components  used  in  their  construction. 
 115  With  digital  television  service,  if  a  receivers  adaptive  equalizer  is  unable  to  handle  multipath  the  result  is  no 
 service. 
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 larger  challenge  than  initially  anticipated  and  that  a  high  level  of  ability  to  cope  with  multipath  signals  is  important  to  reception  of  DTV  signals. 
 47.  In  the  Inquiry,  as  directed  by  Section  339(  c)(  1)(  B)(  v)  we  requested  comment  and  information  on  whether  there  is  a  wide  variation  in  the  ability  of  reasonably  priced  consumer  digital  television  sets  to 
 receive  over-  the-  air  signals,  so  that  at  given  signal  strengths  some  sets  are  able  to  display  high-  quality  pictures  while  other  sets  cannot,  and  if  so,  whether  this  variation  is  related  to  the  price  of  the  television 
 set.  As  further  directed  by  Section  339(  c)(  1)(  B)(  v),  we  also  requested  comment  on  whether  such  variation  should  be  factored  into  setting  a  standard  for  determining  whether  a  household  is  unserved  by  an 
 adequate  digital  signal.  In  considering  these  questions,  we  note  that  the  nature  of  digital  television  operation  is  such  that  a  receiver  will  provide  a  high-  quality  picture  (consistent  with  its  display 
 capabilities)  at  all  signal  levels  at  or  above  its  threshold  of  service.  116  When  the  received  signal/  field  strength  falls  below  the  minimum  service  threshold  there  is  a  very  sudden  loss  of  service  that  occurs  over 
 a  signal  strength  change  of  less  than  1  dB.  This  sudden  loss  of  picture  service,  which  first  appears  as  blocking  and  freezing  of  portions  of  the  image,  is  called  the  DTV  cliff  effect.  This  operating 
 characteristic  is  in  contrast  to  analog  TV  service  in  which  picture  quality  degrades  gradually  as  signal  strength  declines.  Thus,  we  will  assume  in  our  evaluation  of  digital  television  receiver  performance  that 
 picture  quality  remains  high  at  all  signal/  field  strength  levels  above  the  minimum  threshold  needed  for  service. 


 48.  In  the  Inquiry,  we  specifically  requested  that  commenting  parties  provide  information  regarding  the  sensitivity  of  various  receivers  and  their  interference  rejection  capability.  We  asked  that 
 this  technical  information  be  accompanied  by  price  data  and  analysis  regarding  the  correlation  between  performance  and  price.  Finally,  we  asked  if  there  are  significant  differences  in  digital  receiver 
 performance  quality  and,  if  so,  should  those  differences  be  factored  into  the  determination  of  whether  a  household  is  unserved  by  an  adequate  digital  signal.  The  Commissions  Laboratory  staff  also  undertook  a 
 technical  measurement  study  of  the  performance  capabilities  of  a  sample  of  the  digital  television  receivers  currently  on  the  market,  looking  at  noise  figure,  S/  N/  ratio,  adaptive  equalizer/  multipath  handling 
 performance,  and  price. 
 49.  Inquiry  Record.  With  regard  to  DTV  receiver  noise  figure  performance,  dLR  states  that  it  has  not  independently  tested  a  representative  sample  of  DTV  receivers  for  their  noise  figure  performance  and 


 assumed  that  information  would  be  developed  from  the  Commissions  receiver  study  in  this  matter.  117  MSW  and  the  NAB  submit  that  while  there  is  little  published  data  about  receiver  noise  figures,  consumers 
 can,  in  any  event  make  the  noise  figure  of  a  receiver  irrelevant  by  employing  an  inexpensive  preamplifier.  118 


 50.  Concerning  the  DTV  receiver  S/  N  ratio,  dLR  states  that  laboratory  measurements  by  Bouchard,  et  al.,  of  the  Communications  Research  Center  Canada  (CRC)  in  late  2000  (Bouchard  study) 
 demonstrate  S/  N  levels  consistent  with  the  Commissions  assumed  value  of  15.2  dB  for  this  planning 


 116  Digital  television  receivers  are  typically  designed  to  provide  picture  quality  at  one  of  several  maximum  quality 
 levels:  standard  definition  (similar  to  analog  480i  service),  enhanced  definition  (480p  or  640p),  or  high  definition  (720p  or  1080i).  The  price  of  receivers  generally  increases  with  higher  picture  quality  capability. 


 117  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  8. 
 118  NAB  comments  at  22,  Att.  1  (Engineering  Statement  of  MSW)  at  17. 
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 factor.  119  The  measurements  in  this  study  were  conducted  on  a  sample  of  six  DTV  receivers  manufactured  in  the  period  1999-  2000.  For  a  weak  desired  signal,  the  study  found  a  S/  N  range  or  15.3 
 dB  to  17.  8  dB,  with  a  median  S/  N  of  15.  6  dB.  The  five  best  out  of  the  six  had  a  S/  N  of  15.3  dB  to  16.6  dB  with  a  median  S/  N  of  15.  4  dB.  120  dLR  further  states  that  laboratory  measurements  by  the  CRC  on  a 
 Zenith  fifth  generation  DTV  receiver  in  September  2003  also  show  S/  N  measurement  results  that  are  consistent  with  the  Commissions  planning  factor  value.  121  dLR  submits  that  these  results  show  a 
 measured  S/  N  of  15.9  dB  in  the  presence  of  a  weak  signal  level,  which  is  within  .7  dB  of  the  planning  factor  value  and  indicates  that  the  latest  generation  of  DTV  receivers  will  perform  in  line  with  those  of 
 earlier  manufacture. 
 51.  EchoStar  argues  that  the  DTV  signal  strength  standards  should  be  revised  upwards  because  the  signal  sensitivities  of  the  current  generation  of  consumer  DTV  receivers  can  be  significantly  worse 


 than  the  signal  sensitivities,  i.  e.,  S/  N  ratio  plus  noise  figure,  assumed  in  the  planning  factors  for  UHF  and  VHF  reception.  122  It  argues  that  as  a  result  of  this  difference  in  performance  versus  assumption,  many 
 consumer  DTV  sets  may  not  be  able  to  display  a  DTV  picture  even  when  the  signal  strength  meets  the  Commissions  standards.  In  support  of  EchoStars  position,  H&  E  evaluated  five  DTV  receivers  for 
 sensitivity  in  comparison  to  the  DTV  planning  factor  values.  123  H&  E  submits  that  its  results  show  that  the  measured  sensitivities  range  as  much  as  6.6  dB  higher  than  the  planning  factor  values  of  -81.4  dBm 
 and  -84.4  dBm,  that  the  receivers  differed  in  sensitivity  by  2-  6  dB  under  favorable  field  conditions,  e.  g.,  no  multipath  signals,  and  the  average  receiver  in  its  study  was  2.6  dB  less  sensitive  than  the  planning 
 factor  value.  In  its  reply  comments,  ATI  points  out  that  the  H&  E  study  considered  older  receivers  that  did  not  conform  to  the  ATSC  A/  74  receiver  performance  standards  or  incorporate  current  models  of  VSB 
 demodulators  and  so  it  is  not  surprising  that  the  receivers  H&  E  tested  suffer  from  the  shortcomings  that  the  fifth  generation  of  VSB  demodulators  was  designed  to  resolve.  124 


 52.  EchoStar  and  H&  E  submit  that  multipath  handling  capability  can  affect  a  digital  television  receivers  ability  to  provide  service.  125  They  state  that  multipath  can  be  measured  and  its  severity  can  be 
 expressed  as  a  signal  strength  penalty  caused  by  the  adaptive  equalizer  in  a  receiver  attempting  to  compensate  for  the  multipath.  H&  E  states  that  a  receivers  adaptive  equalizer,  in  attempting  to 
 compensate  for  the  multipath  will  increase  the  systems  noise  level  at  the  frequencies  of  compensation.  H&  E  submits  that  at  a  good  receiver  location  with  little  multipath,  the  adaptive  equalizer  tap  energy 
 might  be  about  -10  dB,  corresponding  to  a  white  noise  penalty  of  less  than  0.5  dB  and  that  at  a  poor 
 119  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  8  and  n.  3  (citing  Bouchard,  Pierre,  et  al.,  Digital 
 Television  Test  Results    Phase  I,  Communications  Research  Centre  (Ottawa,  Canada),  CRC  Report  No.  CRC-RP-  2000-  11,  November  2000). 


 120  The  worst  performing  receiver  in  the  Bouchard  study  was  the  oldest  measured  unit. 
 121  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  8-  9  and  n.  4  (citing  Results  of  the  Laboratory 
 Evaluation  of  Zenith  5  th  Generation  VSB  Television  Receiver  for  Terrestrial  Broadcasting,  Report  Version  1.  1,  Communications  Research  Centre  Canada,  September  2003). 


 122  EchoStar  comments  at  4  and  Att.  A  (Engineering  Statement  of  H&  E)  at  12-  13. 
 123  EchoStar  comments,  Att.  A  (Engineering  Statement  of  H&  E)  at  12-  13.  Three  of  the  receivers  in  the  H&  E 
 study  were  obtained  from  retailers  in  May  2005,  the  fourth  was  an  older  model  purchased  in  2000,  and  the  fifth  was  a  professional  ATSC  demodulator. 


 124  ATI  reply  comments  at  2. 
 125  EchoStar  comments  at  5  and  Att.  A  (Engineering  Statement  of  H&  E)  at  8-  9. 
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 location  the  white  noise  penalty  may  exceed  2  dB.  H&  E  further  states  that  laboratory  tests  by  others  showed  that  receiver  sensitivity  decreased  on  the  order  of  0-  5.3  dB  in  the  presence  of  multipath.  126 
 53.  Other  commenting  parties  generally  observe  that  in  the  early  stages  of  the  DTV  transition,  multipath  was  found  to  be  much  more  difficult  for  digital  TV  reception  than  it  was  for  analog  TV 
 reception.  dLR,  MSW,  the  NAB  and  the  Network  Affiliates  state  that  the  fifth  generation  DTV  receivers  now  commercially  available  in  integrated  sets  from  manufacturers  such  as  LG  and  Zenith  have  made 
 substantial  improvements  in  equalizer  architecture  and  can  now  handle  50  microsecond  pre-  ghosts  and  50  microsecond  post-  ghosts.  127  dLR  submits  that  a  paper  by  Tim  Laud  of  Zenith  reports  laboratory  results 
 demonstrating  fifth  generation  equalizer  capability  to  handle  ghosts  of  up  to  50  microseconds  and  at  a  level  of  100%  (that  is,  the  ghost  reflection  would  be  at  the  same  level  as  the  principal  signal).  128  dLR, 
 MSW,  and  NAB  note  that  Tim  Lauds  paper  also  reports  on  field  tests  on  fifth  generation  receivers  in  Washington,  DC,  Ottawa,  Canada,  and  Baltimore,  MD,  where  significant  improvements  in  performance 
 at  known  difficult  locations  were  demonstrated.  dLR  states  that  in  these  field  tests,  fifth  generation  receivers  showed  improvements  ranging  from  an  elimination  to  near  elimination  of  failures  (in  the  Ottawa 
 and  Baltimore  tests)  to  a  reduction  in  failures  by  a  factor  of  three  (in  the  Washington  tests).  ATI,  a  manufacturer  of  electronic  components  including  DTV  receiver  chips,  recommends  that  in  evaluating 
 multipath,  the  Commission  specify  the  multipath  field  ensembles  set  forth  in  the  ATSCs  A/  74  Recommended  Practice:  Receiver  Performance  Guidelines.  It  submits  that,  in  contrast  to  the  field 
 ensembles,  the  laboratory  ensembles  referenced  in  that  document  do  not  provide  an  adequate  basis  for  predicting  how  well  a  receiver  will  perform  in  the  field.  129 


 54.  The  Network  Affiliates  submit  that  because  multipath  is  not  a  function  of  signal  strength  per  se  and  because  current  fifth  generation  receivers  can  handle  multipath  even  in  generally  poor  reception 
 conditions,  the  Commissions  DTV  planning  factors  do  not  need  to  be  adjusted  to  account  for  multipath  by  increasing  the  value  of  the  minimum  field  strength  assumed  to  be  needed  to  receive  service.  130  The 
 Network  Affiliates  state  that  the  effects  of  multipath  can  be  mitigated  greatly,  if  not  wholly,  by  the  use  of  the  latest  generation  receiver,  by  the  use  of  an  outdoor  antenna  raised  to  9  meters/  30  feet  that  will  place 
 the  antenna  above  the  principal  multipath  reflectors  (e.  g.,  moving  vehicles  and  neighboring  residences),  and  by  the  use  of  highly  directional  antennas  with  high  front-  to-  back  ratios,  properly  oriented  to  the 
 strongest  desired  signal.  131  They  point  out  that  the  ATSC  has  stated  that  [  A]  n  antenna  with  a  directional 


 126  EchoStar  comments,  Att.  A  (Engineering  Statement  of  H&  E)  at  12  and  nn.  37-  38.(  citing  Charles  Einhoff,  DTV 
 Receiver  Performance  in  the  Real  World,  Proceedings  of  the  NAB  Broadcast  Engineering  Conference,  2000,  and  Bernard  Caron,  et  al.,  ATSC  8-  VSB  Receiver  Performance  Comparison,  Proceedings  of  the  NAB  Broadcast 


 Engineering  Conference,  2000). 
 127  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  8-  9;  NAB  comments  at  39-  40  and  Att.  1 
 (Engineering  Statement  of  MSW)  at  35-  43;  Network  Affiliates  comments  at  29-  31. 
 128  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  9  and  n.  5  (citing  Tim  Laud,  et  al.,  Performance  of 
 5  th  Generation  8-  VSB  Receivers,  IEEE  Transactions  of  Consumer  Electronics,  Vol.  50,  No.  4,  Nov.  2004,  and  Yiyan  Wu,  et  al.,  An  ATSC  DTV  Receiver  With  Improved  Robustness  to  Multipath  and  Distributed 


 Transmission  Environments,  IEEE  Transactions  on  Broadcasting,  Vol.  50,  No.  1,  March  2004). 
 129  ATI  comments  at  3-  5.  ATI  also  indicates  that  in  cooperation  with  its  customers  in  all  affected  industries  it  has 
 developed  a  robust  test  procedure  and  grading  system  for  evaluating  multipath  based  on  the  A/  74  field  ensembles.  See  id.  at  5-  7  and  Att.  B  (ATI  White  Paper,  June  2005). 


 130  Network  Affiliates  comments  at  30. 
 131  Id.  at  37. 
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 pattern  that  gives  only  a  few  dB  reduction  in  a  specific  multipath  reflection  can  dramatically  improve  the  equalizers  performance.  Such  modest  directional  performance  can  be  achieved  with  antennas  of 
 consumer-  friendly  size,  especially  at  UHF.  132  Further,  the  Network  Affiliates  observe  that  there  is  no  principled  basis  to  include  multipath  in  the  distant  signal  eligibility  standards  since  there  still  remains  no 
 objective  means  to  predict  or  evaluate  multipath  at  any  particular  location  or  to  evaluate  the  impact  of  multipath  on  local  television  service  generally. 


 55.  ATI  submits  that  the  current  DTV  receiver  marketplace  offers  end-  users  superior  performance  that  is  highly  affordable,  with  market  trends  projecting  increasing  affordability  and 
 performance  as  manufacturers  integrate  the  latest  generations  of  DTV  receiver  chips  into  their  products.  133  ATI  and  the  Network  Affiliates  state  that  variations  in  DTV  set  prices  should  play  no  role  in 
 determining  whether  a  household  is  unserved  by  an  adequate  DTV  network  signal.  134  They  state  that  there  is  as  yet  very  little  consumer  penetration  of  DTV  receivers  and  that  most  households  will  therefore 
 have  or  will  acquire  DTV  receivers  with  integrated  tuners  incorporating  the  latest  generational  chip  design  (fifth  generation  or  later),  including  adaptive  equalizers  with  superior  multipath  handling 
 performance  capabilities.  ATI  states  that  neither  price  nor  brand  name  indicates  to  consumers  the  performance  of  DTV  receivers  and  using  the  best  chips  does  not  necessarily  cost  more.  135  It  submits  that 
 as  a  result,  consumers  lack  sufficient  information  for  purchasing  products  based  on  DTV  receiver  performance.  CEA  submits  that  in  a  market  guided  by  competition  and  not  Government  intervention,  it 
 should  be  expected  that  there  will  be  products  that  optimize  for  different  parameters.  136  CEA  states  that  these  variations  are  relatively  small,  as  every  manufacturer  is  motivated  by  competition  to  build  good 
 receivers,  but  the  variations  still  serve  the  market.  For  example,  it  states  that  a  DTV  receiver  that  has  relatively  poor  weak  signal  reception  as  compared  to  every  other  receiver  in  the  market  might  have 
 excellent  selectivity  and  prove  to  be  the  ideal  receiver  for  a  particular  location  with  closely  packed  channels.  Conversely,  CEA  states  that  even  if  the  Commission  were  to  determine  that  there  is  very  little 
 variation  in  the  ability  of  existing  DTV  sets  to  receive  over-  the-  air  signals,  those  same  sets  when  connected  to  the  many  different  available  antennas  and  placed  in  the  infinitely  complex  RF  environment 
 will  certainly  demonstrate  a  wide  variation  in  reception  capability. 
 56.  The  Network  Affiliates  submit  that  with  digital  tuners  manufactured  in  mass  quantities  to  satisfy  the  Commissions  digital  tuner  mandate,  the  cost  of  an  integrated  DTV  set  is  not  particularly 


 dependent  on  the  cost  of  the  generation  of  chip  design  (for  example,  fourth  generation  vs.  fifth  generation).  137  Instead,  they  argue  that  DTV  set  prices  are  largely  dependent  on  features  such  as  ATSC 
 format/  resolution  capabilities  (standard  definition,  enhanced  definition,  and  high  definition),  screen  size,  screen  technology  (CRT,  plasma,  LCD,  DLP),  contrast  ratio,  and  integration  of  other  functions  such  as 
 digital  video  recorders.  The  Network  Affiliates  submit  that  a  survey  of  the  Sharp  Aquos  and  LG  websites  revealed  no  difference  in  the  type  of  ATSC  tuner  included  in  integrated  DTV  sets  within  each 
 manufacturers  product  lines.  They  state  that  it  would  be  inconsistent  with  the  principal  of  localism  and  the  objective  standards  Congress  has  always  imposed  on  the  unserved  household  definition  to  permit  a 


 132  Id.  (citing  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  Doc.  A/  74  (June  18,  2004)  at  24). 
 133  ATI  comments  at  7-  9. 
 134  Id.;  Network  Affiliates  comments  at  35-  37. 
 135  ATI  comments  at  7-  9. 
 136  CEA  comments  at  4-  5. 
 137  Network  Affiliates  comments  at  36. 
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 satellite  carrier  to  deliver  a  duplicating  distant  network  signal  to  a  household  merely  because  the  household  had  purchased,  probably  unknowingly,  an  inferior  DTV  set.  They  note  that  the  current  analog 
 unserved  household  definition  is  not  dependent  on  whether  a  household  buys  a  $59  13-  inch  television  set  or  a  $400  27-  inch  set.  They  state  that  there  is  no  reasonable  basis  to  make  such  a  distinction  in  the 
 digital  context. 
 57.  FCC  Laboratory  Receiver  Study.  In  order  to  obtain  additional  information  on  the  performance  of  DTV  receivers,  the  Commissions  Laboratory  conducted  a  technical  measurement  study 


 (FCC  Study)  of  a  sample  of  28  DTV  receivers  currently  available  on  the  market.  138  The  objectives  of  this  study  were  to  provide  empirical  information  on  the  minimum  signal  level  needed  by  consumer  DTV 
 receivers  to  provide  service  and  whether  the  minimum  signal  level  needed  to  provide  service  varies  across  DTV  receivers  by  price.  It  also  examined  these  receivers  with  respect  to  their  S/  N  ratios,  inferred  noise-figures, 
 and  performance  in  the  presence  of  multipath  reflections  using  47  of  the  50  ATSC  recommended  difficult  reflection  captures,  or  ensembles.  139  Tests  were  performed  on  three  TV  channels  (channels 
 3,  10,  and  30)  in  order  to  evaluate  performance  in  the  low  VHF,  high  VHF,  and  UHF  bands,  respectively.  The  study  receiver  sample  consisted  of  28  products  in  two  categories,  set-  top-  boxes  (STBs)  and 
 integrated  DTV  receivers.  STBs  were  included  because  connection  of  an  STB  to  an  existing  television  set  represents  the  lowest-  cost  alternative  for  DTV  reception.  All  receivers  were  standard,  off-  the-  shelf 
 consumer  products  currently  on  the  market  and  were  provided  on  our  request  by  their  manufacturers.  In  examining  the  components  of  DTV  receiver  performance,  the  study  considered  that  the  minimum  signal 
 level  needed  to  receive  service  is  determined  by  the  combined  influence  of  the  effective  internal  noise  created  by  a  receivers  internal  circuitry  (noise  figure),  signal-  to-  noise  ratio  (also  termed  white  noise  S/  N 
 threshold),  and  thermal  noise,  as  included  in  the  DTV  planning  factors.  The  minimum  signal  level  needed  to  receive  service  is  the  threshold  level  at  which  errors  become  visible  in  the  displayed  picture, 
 i.  e.,  threshold  of  visibility  (TOV).  Thus,  we  have: 
 Minimum  Signal  at  TOV  (dBm)  =  Thermal  Noise  (dBm)  +  Noise  Figure  (dB)  +  Required  CNR  (dB)  140 


 58.  The  receivers  were  measured  in  the  presence  of  conditions  of  white  noise  and  of  the  multipath  reflections  indicated  above.  The  results  were  reported  by  category  (STB  or  integrated  receiver) 
 and  price  range  ($  370  -  $1000,  $1001  -  $2000,  and  $2001  -  $4200).  Brands  and  model  numbers  were  not  reported.  The  results  of  this  study  are  described  below. 


 59.  The  summary  results  for  the  minimum  signal  level  factor  over  all  samples  in  the  white  noise  conditions  are  shown  in  Table  1: 


 138  See  Tests  of  ATSC  8-  VSB  Reception  Performance  of  Consumer  Digital  Television  Receivers  Available  in 
 2005,  OET  Report  FCC/  OET  TR  05-  1017,  Stephen  R.  Martin,  FCC  Laboratory  Division,  November  2,  2005  (FCC  Study).  A  copy  of  this  report  is  attached  hereto  as  Appendix  C. 


 139  See  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced 
 Television  System  Committee,  17  June  2004.  A  multipath  capture  is  a  recording  of  the  multipath  signal  pattern  that  is  present  at  a  given  location.  These  are  also  termed  ensembles  because  a  set  of  specific  reflections,  i.  e., 


 ensemble,  will  be  present  at  any  given  location.  Three  of  the  50  recommended  captures  were  excluded  from  our  Laboratory  testing  because  they  contain  no  video  content  and  therefore  require  specially  instrumented  receivers  for 
 testing. 
 140  Receiver  noise  figures  were  determined  by  inference  from  this  equation  using  the  thermal  noise  figure  common 
 to  all  receivers  and  the  measured  S/  N  for  each  receiver. 
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 MINIMUM  SIGNAL  LEVEL  AT  TOV  Chan  3  Chan  10  Chan  30 
 Planning  factor  values  (dBm)  -81.0  -81.0  -84.0 
 Median  across  all  receivers  (dBm)  -82.2  -83.2  -83.9 
 Difference  from  OET-  69  planning  factors  -1.2  -2.2  0.1 
 Deviations  of  receivers  from  median  (dB)  --  Best  performing  receiver  (dB)  -2.5  -1.7  -1.4 


 --  Worst  performing  receiver  (dB)  12.5  4.  3  2.5  --  90  th  percentile  receiver  (dB)  5.1  3.  1  1.3 
 Standard  deviation  (dB)  3.7  1.  6  0.9  Total  span  from  worst  to  best  receiver  (dB)  15.0  6.  0  3.9 


 Table  1  Statistics  of  Minimum  Signal  Level  at  TOV 
 60.  The  median  minimum  signal  levels  for  the  study  sample  were  slightly  better  -  by  1.2  dB  and  2.2  dB,  respectively    than  the  low-  VHF  and  high-  VHF  planning  factor  value  (-  81.0  dBm)  and  closely 
 matched  the  UHF  planning  value  (-  84.0  dBm).  At  low  VHF,  only  21%  of  the  tested  receivers  performed  more  poorly  in  minimum  signal  level  than  the  performance  measures  modeled  in  OET  Bulletin  No.  69  by 
 an  amount  exceeding  1  dB,  the  approximate  tolerance  of  the  measurements.  141  At  high  VHF  and  UHF,  this  figure  was  11%  and  18%  respectively.  The  variation  among  receivers  at  low  VHF  was  fairly  large, 
 with  a  3.7  dB  standard  deviation.  The  two  receivers  exhibiting  the  poorest  performance  were  at  levels  10.6  dB  and  12.5  dB  worse  than  the  median.  These  two  receivers,  both  the  same  brand,  were  responsible 
 for  much  of  the  variability  and  omitting  them  from  the  results  reduces  the  low  VHF  standard  deviation  to  2.3  dB.  The  third  worst  performer  at  low  VHF  was  6.7  dB  above  the  median.  89%  of  the  receivers  (all 
 but  three)  were  within  5.1  dB  of  the  median  at  low  VHF. 
 61.  The  performance  results  for  the  individual  receivers  are  shown  in  Figure  1: 


 141  The  absolute  measurement  accuracy  of  the  vector  signal  analyzer  on  the  amplitude  range  that  was  used  for  the 
 measurements  was  +/-  1.  5  dB  maximum  and  +/-  0.5  dB  typical. 
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 -90 
 -85 
 -80 
 -75 
 -70 
 -65 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dBm) 


 Chan  3 
 Chan  10 
 Chan  30 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  1.  Measured  Minimum  Signal  Level  at  TOV  on  Three  Channels  142 
 62.  Looking  at  the  variation  of  the  minimum  signal  level  factor  under  the  benign  conditions  by  product  category  and  price,  as  shown  in  Table  2  the  FCC  Study  found: 


 MINIMUM  SIGNAL  LEVEL  AT  TOV  (difference  from  the  median  by  category  and  price)  Chan  3  Chan  10  Chan  30 
 Difference  of  Set-  Top  Boxes  from  Overall  Median  (dB)  2.0  0.5  0.7 
 Difference  of  Low-  Price  DTVs  from  Overall  Median  (dB)  -1.1  -0.2  -0.2 
 Difference  of  Medium-  Price  DTVs  from  Overall  Median  (dB)  0.0  0.5  0.0 
 Difference  of  High-  Price  DTVs  re  Overall  Median  (dB)  -0.7  -0.3  0.0 


 Table  2  Product-  Type  Variations  of  Minimum  Signal  at  TOV 


 63.  This  chart  shows  that  the  observed  variations  in  minimum  signal  level  across  product  and  price  categories  were  very  small.  The  category  medians  for  high  VHF  and  UHF  differ  from  the  overall 
 median  by  less  than  1  dB  and  for  low  VHF  differ  by  only  2.0  dB.  At  low  VHF  the  median  performance  of  the  set-  top  boxes  was  2.0  dB  worse  than  the  overall  median  of  all  receivers  and  the  best  median 
 performance  was  achieved  by  the  low-  price  DTV  receiver  category,  which  slightly  outperformed  the  medium  and  high-  priced  categories.  At  low-  VHF,  the  median  of  the  highest  priced  sets  was  only  0.7  dB 


 142  The  letter/  number  designations  indicate  the  individual  receivers  tested. 
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 Federal  Communications  Commission  FCC  05-  199 
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 better  than  the  overall  median.  In  the  high  VHF  and  UHF  bands  the  performance  differences  from  the  overall  median  were  even  less.  Most  of  the  differences  in  median  values  between  categories  are  so  small 
 as  to  be  considered  insignificant.  We  believe  that  even  the  largest  of  these  differences  would  affect  perceived  performance  only  in  locations  where  the  signal  margin  was  very  small  and  in  the  general  case 
 would  not  be  noticeable  to  consumers  at  all. 
 64.  The  FCC  study  found  that  the  white-  noise  S/  N  threshold  for  the  median  receiver  in  the  sample  was  15.3  dB,  only  0.1  dB  above  (worse  than)  the  planning  factor  value.  The  white-  noise  S/  N 


 threshold  results  are  summarized  in  Table  3: 


 WHITE  NOISE  S/  N  THRESHOLD 
 Planning  Factor  Value  (dBm)  15.2 
 Median  across  all  receivers  (dBm)  15.3 
 Difference  from  OET-  69  planning  factor  0.1 
 Deviations  of  receivers  from  median  (dB)  --  Best  performing  receiver  (dB)  -0.4 


 --  Worst  performing  receiver  (dB)  0.5  --  89th  percentile  receiver  (dB)  0.3 
 Standard  deviation  (dB)  0.2  Total  span  from  best  to  worst  receiver  (dB)  0.8  143 


 Table  3  Statistics  of  White  Noise  Threshold 
 65.  These  results  show  that  the  variations  in  S/  N  performance  among  receivers  is  quite  small,  with  the  standard  deviation  of  the  S/  N  measurements  across  all  of  the  sample  receivers  amounting  to  only 
 0.2  dB.  The  total  range  from  best  to  worst  performing  receiver  was  0.8  dB,  with  the  worst  performing  receiver  only  0.5  dB  above  the  median  performance.  Similar  lack  of  variation  in  S/  N  performance  was 
 found  with  respect  to  price,  as  shown  in  Table  4.  The  median  performance  of  the  least  expensive  receivers,  the  STBs,  was  only  0.1  dB  worse  than  the  overall  median.  The  median  low-  cost  and  mid-  cost 
 integrated  sets  performed  at  the  median,  while  the  median  high-  cost  integrated  set  performance  is  only  0.2  dB  better  than  the  overall  median. 


 WHITE  NOISE  THRESHOLD 
 Difference  of  Set-  Top  Boxes  from  Overall  Median  (dB)  0.1 
 Difference  of  Low-  Price  DTVs  from  Overall  Median  (dB)  0.0 
 Difference  of  Medium-  Price  DTVs  from  Overall  Median  (dB)  0.0 
 Difference  of  High-  Price  DTVs  from  Overall  Median  (dB)  -0.2 


 Table  4  Product-  Type/  Price  Variations  of  White  Noise  Threshold 


 143  The  span  does  not  match  the  difference  between  worst  and  best  performing  receivers  due  to  the  rounding  of 
 results  to  the  nearest  0.1  dB. 
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 66.  The  study  derived  the  receivers  inferred  noise  figure  performance  from  the  measurements  of  minimum  signal  level  and  S/  N  level  under  benign  conditions  and  using  -106.2  dBm  as  the  value  for 
 thermal  noise.  The  inferred  noise  figure  values  are  shown  in  Table  5. 


 NOISE  FIGURE  Chan  3  Chan  10  Chan  30  Planning  Factor  Values  10  10  7 
 Median  across  all  receivers  (dBm)  8.8  7.6  6.9 
 Difference  from  OET-  69  planning  factors  -1.2  -2.4  -0.1 
 Deviations  of  receivers  from  median  (dB)  --  Best  performing  receiver  (dB)  -2.5  -1.3  -1.3 


 --  Worst  performing  receiver  (dB)  12.2  4.5  2.6  --  89th  percentile  receiver  (dB)  4.5  3.3  1.2 
 Standard  deviation  (dB)  3.6  1.6  0.9  Total  span  from  worst  to  best  receiver  (dB)  14.7  5.7  3.9 


 Table  5  Statistics  of  Receiver  Noise  Figure 
 67.  These  data  show  that  the  noise  figures  for  the  currently  available  receivers  in  the  FCC  study  are  generally  better  than  the  planning  factor  values  by  1  or  2  dB  at  low  and  high  VHF  and  are  the  same  as 
 the  planning  factor  value  at  UHF.  There  is  considerable  variation  in  the  sample  receivers  noise  figure  performance  at  low  VHF,  with  a  standard  deviation  of  3.6  dB  and  with  two  receivers  performing  at  levels 
 10.3  dB  and  12.2  dB  worse  than  the  median.  However,  89%  of  the  receivers  (all  but  three)  were  no  more  than  4.5  dB  above  (worse  than)  the  median  performance  at  VHF. 


 68.  As  shown  in  Table  6,  the  observed  variations  in  noise  figure  with  product  category  and  price  were  small,  with  the  category  medians  differing  from  the  overall  median  by  less  than  1  dB  for  channels  at 
 high  VHF  and  at  UHF,  but  were  slightly  larger  at  low  VHF.  At  low  VHF  the  median  performance  of  set-top  boxes  was  1.7  dB  worse  than  the  overall  median  of  all  receivers,  and  the  median  performance  of  the 
 highest  priced  TV  category  was  0.8  dB  better  than  the  median.  The  best  median  noise  figure,  1.4  dB  better  than  the  overall  median,  occurred  in  the  lowest  priced  integrated  receiver  category.  Such 
 differences  as  shown  in  Table  6  are  likely  to  influence  performance  only  in  locations  where  the  signal  margin  is  very  small  and  generally  would  not  be  noticeable  to  consumers. 


 NOISE  FIGURE  Chan  3  Chan  10  Chan  30 
 Difference  of  Set-  Top  Boxes  from  Overall  Median  (dB)  1.7  0.1  0.6 
 Difference  of  Low-  Price  DTVs  from  Overall  Median  (dB)  -1.4  -0.1  0.1 
 Difference  of  Medium-  Price  DTVs  from  Overall  Median  (dB)  0.0  0.4  -0.1 
 Difference  of  High-  Price  DTVs  from  Overall  Median  (dB)  -0.8  -0.3  0.0 


 Table  6  Product-  Type/  Price  Variations  of  Receiver  Noise  Figure 
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 69.  Finally,  measurements  of  the  performance  of  the  sample  DTV  receivers  in  the  presence  of  the  47  multipath  ensembles  are  shown  in  Figure  2:  144 
 0 
 5 
 10 
 15 
 20 
 25 
 30 
 35 
 40 
 45 


 A1  D1  E1  G1  H1  D2  E2  G2  J1M1R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2M2N1  O1 
 2000REF  Receiver 


 # 
 of 


 RF 
 Captures 


 Successfully 


 Played 
 Back 
 (of 
 47) 


 1-  2  Errors 
 No  Errors 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs  $2001  -  $4200  Better 


 Worse 
 Figure  2  Performance  against  47  RF  Captures 
 70.  Unlike  the  results  for  white  noise  performance,  the  results  of  testing  against  the  RF  captures  were  heavily  clustered  into  two  performance  tiers.  145  The  better  performers  successfully  played  29 
 captures  without  error  and  about  37  captures  with  two  or  fewer  errors.  The  lower  tier  performers  successfully  played  about  7  captures  without  error  and  about  9  with  two  or  fewer  errors.  Except  for 


 144  In  this  testing,  each  receiver  was  subjected  to  exactly  the  same  multipath  conditions  for  each  capture  (the 
 captures  are  recordings).  The  lower  portion  of  each  bar  represents  the  number  of  captures  that  played  without  a  visible  error  during  a  single  loop,  i.  e.,  recording  of  the  capture  (a  recording  of  multipath  capture  is  played 


 continuously  in  a  loop).  The  upper  portion  of  each  bar  adds  the  captures  that  played  with  no  more  than  two  visible  errors  during  a  single  loop  of  capture.  This  chart  also  includes  a  bar  on  the  right  showing  the  results  for  the 
 reference  receiver  used  the  FCC  field  tests  in  2000,  see  A  Study  of  ATSC  (8-  VSB  DTV  Coverage  in  Washington,  DC,  and  Generational  Changes  in  DTV  Receiver  Performance,  (Interim  Report)  OET  Report,  FCC/  OET  TRB-00- 
 2  (2001  FCC  Field  Test  Receiver  Study),  William  H.  Inglis  and  David  L.  Means,  February  2,  2001. 
 145  It  should  be  noted  that  some  of  the  RF  captures  may  contain  recording  flaws  that  could  prevent  error-  free 
 demodulation  regardless  of  how  advanced  the  demodulator  technology  may  be,  see  FCC  Study,  supra  note  138,  at  6-  3.  For  example,  four  of  the  captures  for  which  no  tested  receiver  achieved  demodulation  free  of  visual  errors 


 were  identified  by  the  ATSC  as  having  possible  non-  linearities  caused  by  high-  level  adjacent  channels  overdriving  the  recording  system.  These  or  other  potential  flaws  may  preclude  a  100%  success  rate  on  the  47  captures  from 
 ever  being  achieved  by  any  demodulator.  Thus,  the  FCC  Study  views  the  multipath  performance  data  based  on  these  captures  to  be  useful  for  purposes  of  comparing  receivers,  but  not  as  an  absolute  measure  of  performance. 
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 Federal  Communications  Commission  FCC  05-  199 
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 receivers  D1  and  L2,  all  results  fall  within  2  captures  of  one  of  these  nominal  results.  Receivers  D1  and,  perhaps,  L2  appear  to  represent  an  additional  performance  level  slightly  above  the  lower  tier.  The  upper 
 tier  performers  provide  a  significant  improvement  in  the  ability  to  handle  the  most  difficult  multipath  conditions.  146  The  tested  receivers  in  this  tier  are  known  to  include  the  latest  generation  of  demodulator 
 chips  from  at  least  two  of  the  major  DTV  chip  manufacturers.  The  results  on  Figure  2  are  summarized  in  Table  7. 


 Number  of  Consumer 
 Receivers  Number  of  Captures  Played  with  No  Errors  Number  of  Captures  Played  with  No  More  Than  2  Errors  Lower  Tier  16  7  2  9  +2/-  1 
 Lower  Tier+  2  8  and  12  14  and  16  Upper  Tier  10  29  2  37  2 


 Table  7  Number  of  Captures  Successfully  Played  By  Each  Performance  Tier  (Out  of  47  Captures) 


 71.  Looking  next  at  the  variation  of  multipath  handling  performance  with  product  type  and  price,  the  FCC  Study  found  that  while  none  of  the  STBs,  which  are  all  of  older  design,  perform  at  the  upper  tier 
 level,  upper  and  lower  tier  performing  products  appear  in  all  three  price  categories  of  integrated  receivers.  This  suggests  that  multipath  handling  performance  is  not  a  function  of  price.  Among  the  integrated 
 receivers,  the  study  found  that  introduction  dates  in  or  after  March  2005  were  consistent  with  the  likelihood  of  including  newer  technology.  Among  the  tested  receivers  that  were  introduced  on  or  after 
 March  1,  2005,  48%  were  found  to  perform  at  the  upper  tier  level.  The  study  also  notes  that  it  is  probable  that  some  of  the  products  introduced  in  this  time  frame  carried  over  tuner/  demodulator  designs  from  a 
 previous  generation. 
 72.  In  reviewing  these  results,  the  FCC  Study  also  considered  that  there  might  be  some  reason  to  expect  that  improvements  in  multipath  performance  -  which  is  achieved  in  part  by  increasing  the  number 


 of  taps  in  the  demodulators  equalizer  circuit  -  might  come  at  the  expense  of  a  reduced  white  noise  threshold,  because  the  additional  taps  could  be  expected  to  add  noise  that  is  related  to  carrier  amplitude.  147 
 Figure  3  shows  measurements  of  white  noise  threshold  plotted  against  multipath  performance  as  measured  by  the  number  of  RF  captures  (out  of  47)  that  were  successfully  played  without  error.  The 
 lower  tier  of  multipath  performers  (presumably  containing  earlier  generation  VSB  decoders)  had  a  median  S/  N  threshold  of  15.  3  dB,  slightly  worse  than  the  15.2  dB  threshold  achieved  by  the  ACATS 
 Grand  Alliance  prototype  receiver.  The  15.1  dB  median  S/  N  ratio  for  the  upper  tier  of  multipath  performers  suggests  that  the  characteristic  of  a  worsening  of  S/  N  ratio  as  a  trade-  off  for  multipath  no 
 longer  occurs. 


 146  We  emphasize  that  the  tested  multipath  conditions  are  those  known  to  be  most  difficult  and  are  not  typical  of 
 conditions  that  most  households  will  encounter  in  receiving  digital  television  service. 
 147  Since  an  automatic  gain  control  would  be  expected  to  provide  sufficient  gain  to  amplify  the  input  signal  - 
 whatever  its  level  -  to  a  fixed  level  for  processing  in  the  demodulator,  one  would  expect  that  the  tap  noise  generated  after  this  variable  amplification  would  be  at  a  fixed  level  relative  to  the  DTV  signal  rather  than  at  a  fixed 


 level  relative  to  the  antenna  input  -  hence  the  impact  would  appear  as  a  degradation  to  required  S/  N  (white  noise  threshold)  rather  than  as  an  increase  in  noise  figure. 
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 14.  8 
 14.  9 
 15.  0 
 15.  1 
 15.  2 
 15.  3 
 15.  4 
 15.  5 
 15.  6 
 15.  7 
 15.  8 
 15.  9 


 0  5  10  15  20  25  30  35 
 #  of  Captures  With  No  Visible  Errors 


 White 
 Noise 
 Threshold 


 [Required 
 CNR] 
 (dB) 


 Better 


 Worse 


 Better  Worse 
 Figure  3  White  Noise  Threshold  Versus  Multipath  Performance 
 73.  Evaluation.  Based  on  our  evaluation  of  both  the  Inquiry  record  and  the  FCC  study,  we  conclude  that  neither  the  S/  N  ratio  nor  the  receiver  noise  figure  values  in  the  DTV  planning  factors  should 
 be  modified  in  determining  the  DTV  field  signal  strength  standards  to  be  used  for  determining  whether  a  household  is  eligible  to  receive  retransmitted  network  DTV  signals  from  a  satellite  service.  In  answer  to 
 Section  339(  c)(  1)(  B)(  v),  we  see  no  significant  variability  in  the  ability  of  reasonably  priced  consumer  digital  television  sets  to  receive  over-  the-  air  signals  in  the  high  VHF  and  UHF  bands  such  that  some  sets 
 are  able  to  display  high-  quality  pictures  while  others  cannot,  and  the  variation  that  is  present  does  not  appear  to  be  closely  related  to  price.  We  note  that  in  the  low  VHF  band,  there  were  two  receivers  that 
 were  significant  outliers  and  a  third  receiver  that  was  6.7  dB  above  the  median.  We  find  that  this  few  number  of  receivers  with  high  low-  VHF  thresholds  does  not  obviate  our  general  conclusion  that  price  is 
 not  a  factor  in  the  availability  of  DTV  receivers  that  are  able  to  display  high-  quality  pictures. 
 74.  We  stated  earlier  that  picture  quality  does  not  depend  on  the  level  of  signal  strength.  Rather,  the  importance  of  the  level  of  signal  strength  is  simply  whether  service  can  be  received,  and  the  factors 


 that  determine  that  level  are  a  receivers  S/  N  ratio  and  noise  figure.  Our  FCC  study  results  indicate  that  currently  available  DTV  receivers  are  generally  able  to  provide  service  with  signals  at  levels  very  close  to 
 those  assumed  in  the  planning  factors  and  in  a  few  cases  with  signals  at  lower  levels.  We  did  find  some  variation  in  the  reception  performance  with  respect  to  the  minimum  signal  level  needed  to  provide 
 service,  but  this  was  mostly  at  low  VHF.  In  addition,  H&  E  reported  some  receivers  that  need  higher  minimum  signal  levels  to  provide  service.  We  do  not  view  with  concern  those  products  needing  higher 
 minimum  signal  levels  because  it  is  apparent  that  the  greater  portion  of  products  perform  generally  on  a  par  with  the  planning  factor  value.  Given  that  a  large  number  of  receivers  performed  well  at  signal  levels 
 at  or  close  to  the  minimum  signal  level  assumed  by  the  planning  factors,  we  do  not  believe  that  there  are 
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 any  technical  difficulties  in  providing  performance  that  meets  the  planning  factor  target.  We  believe  that  it  is  best  to  rely  on  market  forces  to  determine  whether  those  products  or  perhaps  others  performing  at 
 similarly  high  threshold  levels  remain  available  to  consumers.  At  high  VHF  and  UHF,  the  variation  in  reception  performance  among  the  receivers  in  our  FCC  study  was  small. 


 75.  As  indicated  above,  we  also  find  no  indication  that  increasing  price  levels  are  associated  with  improved  minimum  signal  level  performance.  With  the  exception  of  set-  top  boxes,  in  fact,  it  appears  that 
 there  is  very  little  relationship  between  price  and  the  minimum  signal  level  needed  to  provide  service.  Because  the  set-  top  boxes  studied,  and  indeed  all  of  those  now  on  the  market,  are  of  older  designs,  we 
 believe  that  their  general  design,  rather  than  their  price,  is  the  reason  for  their  somewhat  lower  performance.  Thus  there  do  not  appear  to  be  any  technical  reasons  that  would  impede  the  economical 
 manufacture  of  products  that  perform  at  the  expected  minimum  signal  levels  currently  assumed  in  the  planning  factors  for  the  DTV  field  strength  standards. 


 76.  The  information  on  receiver  signal-  to-  noise  ratios  and  noise  figures  provided  in  the  Inquiry  record  and  from  our  study  indicate  performance  levels  consistent  with  the  minimum  signal  level 
 performance  discussed  above.  This  is  reasonable  given  the  close  relationship  of  the  three  measures.  It  appears  that  most  receivers  now  on  the  market  exhibit  S/  N  performance  within  levels  very  close  to  the 
 15.2  dB  level  assumed  in  the  planning  factors,  and  a  few  perform  slightly  better.  Again,  we  do  not  view  those  products  that  are  5  dB  or  more  above  the  planning  factor  value  for  minimum  signal  level  to  receive 
 service  as  an  indicator  of  a  deficiency  in  the  planning  factor  value,  given  that  so  many  products  do  perform  at  or  near  the  expected  level.  From  our  FCC  study,  it  appears  that  most  of  the  variation  in  the 
 minimum  signal  level  needed  to  provide  service  is  the  result  of  differences  in  receiver  noise  figures  rather  than  S/  N  ratio.  The  noise  figure  variations  were  larger  than  the  minimum  S/  N  ratio  variations  by  factors 
 ranging  from  3.9  dB,  in  the  UHF  band,  to  14.7  dB  in  the  low  VHF  band. 
 77.  We  conclude  that  it  is  not  necessary  to  augment  the  DTV  receiver  planning  factors  with  an  additional  factor  for  multipath.  As  EchoStar  and  others  commenting  in  our  Inquiry  observe,  multipath 


 can  pose  difficulties  for  reception  of  digital  television  signals  and,  at  the  beginning  of  the  DTV  transition,  receiver  adaptive  equalizers  were  not  able  to  adequately  process  many  real  world  multipath  conditions. 
 From  the  record  of  our  Inquiry  and  our  on-  going  monitoring  of  DTV  receiver  performance,  including  the  testing  performed  in  the  FCC  study,  it  is  apparent  that  the  current  generation  of  digital  TV  receivers  is 
 able  to  provide  service  under  most  multipath  conditions  that  they  may  encounter.  This  can  be  seen  from  an  earlier  field  study  by  the  Commission  in  2001  that  examined  DTV  reception  at  a  number  of  sites 
 randomly  selected  throughout  the  Washington,  DC  area.  That  study,  which  was  based  on  second  and  third  generation  receivers,  observed  successful  reception  of  DTV  service  at  99%  of  the  locations  where 
 the  field  strength  was  at  or  above  the  level  expected  to  be  needed  for  service  using  a  mast-  mounted  antenna  at  30  feet.  Similarly,  that  study  found  successful  reception  at  85%  of  the  tested  locations  when 
 using  an  indoor  antenna  outdoors  at  7-  feet.  The  reason  for  that  level  of  successful  reception  with  those  older  receivers  is  that  the  number  of  locations  where  multipath  conditions  are  difficult  is  relatively  low. 
 The  FCC  Study  indicates  that  these  reception  success  rates  were  achieved  using  a  receiver  performing  in  the  lower  tier  of  Figure  2.  Figure  2  demonstrates  that  the  latest  generation  of  equalizer  technology  - 
 represented  by  the  upper  tier  of  Figure  2  -  provides  service  when  subjected  to  most  of  the  difficult  ATSC  multipath  ensembles,  most  of  which  were  recorded  with  indoor  antennas. 


 78.  We  also  considered  the  information  provided  by  EchoStar  and  H&  E  indicating  that,  in  processing  multipath  signals,  a  DTV  receivers  adaptive  equalizer  could  generate  additional  noise  that 
 could  effectively  increase  the  receivers  noise  figure,  and  thus  reduce  its  sensitivity  so  that  a  higher  level  of  input  signal  could  be  needed  to  provide  service.  It  is  true  that  the  process  of  multipath  cancellation  can 
 cause  a  white  noise  enhancement  -  a  degradation  in  performance  that  causes  a  higher  input  S/  N  to  be  required  in  the  presence  of  multipath  than  in  its  absence;  however,  difficult  multipath  conditions  leading 
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 to  degradations  by  as  much  as  2  dB,  as  argued  by  EchoStar  and  H&  E,  are  not  expected  to  be  the  norm.  The  2001  Field  Test  Receiver  Study  demonstrated  that  the  then-  latest  generation  receiver  (with  equalizer 
 technology  that  is  now  obsolete  by  two  generations)  performed  better  in  terms  of  required  S/  N  in  typical  multipath  conditions  than  older  receivers  indicating  a  trend  toward  less  degradation  in  performance  in 
 the  presence  of  multipath  with  successive  generations  of  hardware.  That  receiver  exhibited  a  median  required  S/  N  of  15.9  to  16.  0  dB  across  all  of  the  "coverage  sites"  tested  in  those  field  tests  using  an 
 outdoor-  type  antenna.  This  performance  is  only  0.7  to  0.8  dB  worse  than  the  15.  2-  dB  S/  N  in  the  planning  factors.  148  Though  the  FCC  has  not  tested  the  newer  generations  of  equalizers  in  this  regard,  there  is 
 information  to  suggest  that  the  noise  enhancement  of  the  fifth  generation  is  even  lower  than  past  generations.  149  Furthermore,  the  FCC  Study  notes  that,  if  noise  enhancement  raises  the  required  S/  N  to 
 16.0  dB,  when  this  change  is  combined  with  the  median  measured  noise  figures  of  the  28  tested  receivers,  the  overall  result  is  a  more  optimistic  prediction  than  the  value  stated  in  OET  Bulletin  No.  69  by  0.4  dB 
 and  1.6  dB,  respectively,  in  the  low-  VHF  and  high-  VHF  bands  and  a  less  optimistic  prediction  than  the  current  OET-  69  by  only  0.  7  dB  in  the  UHF  band.  150  Accordingly,  we  do  not  believe  that  a  factor  for 
 multipath  should  be  added  to  the  minimum  signal  level  assumed  to  be  needed  to  receive  DTV  service. 
 3.  Other  Planning  Factors 


 79.  Thermal  Noise  and  Man-  made  Noise.  The  thermal  noise  planning  factor  of  -106.2  dBm  is  based  on  a  6  MHz  bandwidth  channel  and  an  assumed  temperature  of  290  o  K.  As  pointed  out  by  dLR  and 
 the  Network  Affiliates,  thermal  noise  is  a  function  of  the  laws  of  physics  and  has  not  and  will  not  change.  151  We  therefore  find  that  the  planning  factor  value  for  thermal  noise  is  appropriate  and  should 
 not  be  changed. 
 80.  In  their  comments  and  engineering  statement,  EchoStar  and  H&  E  argue  that  the  digital  TV  field  strength  standards  should  be  revised  to  account  for  man-  made  noise.  152  They  contend  that  man-made 


 noise  is  typically  impulse  noise  from  sources  such  as  power  line  arcing,  industrial  machinery,  automotive  ignition  systems,  appliances  having  electric  motors  (vacuums,  dishwashers,  hair  dryers,  etc.), 
 devices  with  switching  power  supplies  (computers),  and  microwave  ovens.  They  submit  that  man-  made  noise  was  not  adequately  taken  into  account  in  the  DTV  planning  factors,  particularly  at  the  low  VHF 
 channels.  EchoStar  and  H&  E  state  that,  as  a  result,  the  Commission  did  not  build  in  a  sufficient  margin  for  noise  when  it  set  the  DTV  signal  strength  standard  for  those  channels.  H&  E  submits  that  a  1974  study 
 by  NTIA  found  that  in  rural  locations  man-  made  noise  levels  are  typically  above  20  dB  and  in  urban  areas  such  noise  is  typically  above  30  dB  near  54  MHz  (channel  2).  153  It  also  states  that  a  more  recent  2001 


 148  The  coverage  sites  measured  in  the  2001  Field  Test  Receiver  Study  were  selected  without  regard  to  multipath 
 conditions.  See  2001  Field  Test  Receiver  Study,  supra  note  144. 
 149  See  e.  g.,  Laud,  Tim,  Aitken,  Mark;  Bretl,  Wayne;  and  Kwak,  K.  Y.,  Performance  of  5th  Generation  8-VSB 


 Receivers,  IEEE  Transactions  on  Consumer  Electronics,  Vol.  50,  No.  4,  November  2004,  which  states  that  the  fifth  generation  receiver  includes  techniques  for  reduced  noise  enhancement. 


 150  See  FCC  Study  at  8-  4. 
 151  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  3-  4;  Network  Affiliates  comments  at  15. 
 152  EchoStar  comments  at  4-  5  and  Att.  A  (Engineering  Statement  of  H&  E)  at  9-  11. 
 153  EchoStar  comments,  Att.  A  (Engineering  Statement  of  H&  E)  at  10  and  n.  29  (citing  A.  D.  Spaulding  and  R.  T. 
 Disney,  Man-  made  radio  noise,  part  1:  estimates  for  business,  residential,  and  rural  areas,  NTIA  Office  of  Telecommunications  Report  OT  74-  38,  June  1974). 
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 NTIA  study  found  that  median  noise  levels  in  Boulder,  Colorado  approached  20  dB  at  137  MHz,  which  it  argues  implies  a  median  value  approaching  30  dB  at  54  MHz.  154  H&  E  contends  that  if  20  dB  or  30  dB  of 
 man-  made  noise  is  added  to  the  thermal  noise  floor,  some  viewers  in  urban  areas  will  be  unable  to  receive  low  VHF  signals  due  to  excessive  man-  made  noise.  EchoStar  and  H&  E  therefore  submit  that  the  signal 
 strength  standard  for  low  VHF  channels  should  be  increased  by  12-  30  dB  to  account  for  such  noise. 
 81.  In  their  reply  comments,  the  Network  Affiliates  state  that  EchoStar  and  H&  E  have  misrepresented  the  results  of  the  NTIA  reports.  155  They  submit  that  the  2001  NTIA  study  cited  by 


 EchoStar  and  H&  E  actually  found  man-  made  noise  at  137  MHz  (between  the  low  VHF  and  high  VHF  bands)  to  be  17.5  dB  in  business  areas  and  only  3.6  dB  in  residential  areas.  156  The  Network  Affiliates 
 state  that  at  UHF  frequencies,  this  study  found  that  it  was  not  possible  to  differentiate  man-  made  noise  from  system  noise,  which  indicates  that  man-  made  noise  is  insignificant  in  the  UHF  band.  They  further 
 submit  that  a  1998  NTIA  study  found  that  residential  man-  made  noise  had  decreased,  amounting  to  no  more  than  3  or  4  dB  in  residential  areas.  157  They  submit  that  if  the  10  dB  receiver  noise  figure  for  VHF 
 channels  is  comprised  of  5  dB  for  receiver  noise  and  5  dB  for  environmental  noise,  then  the  2001  NTIA  study  shows  that  man-  made  noise  at  VHF  frequencies  is  within  the  planning  margin  (as  it  also  is  at  UHF 
 frequencies).  The  Network  Affiliates  therefore  argue  that  EchoStar  and  H&  E  have  provided  no  evidence  to  warrant  adjustment  of  the  digital  TV  signal  strength  standards,  even  at  low  VHF,  for  man-  made  noise. 
 The  NAB  similarly  submits  that  the  2001  NTIA  study  relied  on  by  EchoStar  in  fact  says  exactly  the  opposite  of  what  EchoStar  claims,  namely  that  man-  made  noise  in  residential  areas  is  very  low  -  only  3.6 
 dB.  158  The  NAB  further  states  that  if  the  Commission  were  to  conclude  that  there  is  a  concern  about  man-made  noise  at  low  VHF  channels,  the  way  to  address  it  would  be  to  alter  the  plans  for  the  DTV  transition, 
 for  example,  by  authorizing  low  VHF  channel  stations  to  operate  at  higher  power.  159 
 82.  We  find  that  the  record  does  not  contain  any  current  or  substantial  studies  or  other  information  that  would  indicate  that  man-  made  noise  is  present  in  the  low  VHF  or  other  TV  bands  at 


 levels  that  would  warrant  the  addition  of  this  element  to  the  planning  factors  that  underlie  the  DTV  field  strength  standard.  Given  the  information  on  residential  man-  made  noise  from  both  the  1974  and  2001 
 NTIA  studies,  it  appears  that  the  level  of  man-  made  noise  typically  occurring  on  the  low-  VHF  channels  in  residential  locations  is  only  3  or  4  dB,  a  level  that  is  well  within  the  tolerance  of  the  low-  VHF  noise 
 figure.  We  also  note  that  TV  viewers  are  likely  to  become  aware  of  any  effects  on  their  TV  reception  by  man-  made  noise  arising  from  specific  devices  such  as  hair  dryers,  computers,  microwave  ovens  and 
 similar  appliances  through  the  simple  act  of  turning  those  devices  on  and  off.  The  solution  in  such  cases  is  to  make  sure  that  those  devices  that  might  cause  interference  are  turned-  off  when  someone  is  watching 
 television.  Accordingly,  we  recommend  that  no  revisions  be  made  to  the  DTV  planning  factors  and  field  strength  standards  for  man-  made  noise. 


 154  Id.  at  10  and  n.  30  (citing  Robert  J.  Atchaz  and  Roger  A.  Dalke,  Man-  Made  Noise  Power  Measurements  at 
 VHF  and  UHF  Frequencies,  NTIA  Report  No.  02-  390,  December  2001  (2001  NTIA  study)). 
 155  Network  Affiliates  reply  comments  at  8-  10. 


 156  Id.  at  8  and  n.  25  (citing  2001  NTIA  study,  supra  note  153,  at  25). 
 157  Id.  at  9  and  n.  27  (citing  R.  J.  Achatz  et  al,  Man-  Made  Noise  in  the  136  to  138  MHz  VHF  Meteorological 
 Satellite  Band,  NTIA  Report  98-  355  (Sept.  1998),  at  31). 
 158  NAB  reply  comments  at  11  (citing  2001  NTIA  study,  supra  note  153,  at  25). 


 159  Id.  at  12. 
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 83.  Transmission  (Downlead)  Line  Loss.  The  TV  receive  antenna  and  receiver  are  connected  by  a  transmission  line  that  carries  the  received  signal  to  the  receivers  input  terminal.  The  received  signal 
 will  experience  some  amount  of  attenuation  as  it  travels  over  this  line  due  to  the  lines  inherent  resistance  and  impedance  characteristics.  Today,  most  TV  receiver  systems  use  75-  ohm  shielded  cabling  for  this 
 downlead  connection.  The  1  dB,  2  dB,  and  4  dB  downlead  line  loss  figures  for  low  VHF,  high  VHF,  and  UHF  digital  TV  channels  are  based  on  the  assumed  use  of  50  feet  of  75-  ohm  shielded  cable,  i.  e.,  RG-  6 
 coaxial  cable. 
 84.  In  their  comments  responding  to  our  Inquiry,  dLR,  Jules  Cohen,  MSW,  the  NAB  and  the  Network  Affiliates  submit  that  the  existing  downlead  loss  planning  factor  values  appear  reasonable  in 


 light  of  published  values  for  75-  ohm  RG-  6  cable.  160  The  Network  Affiliates  point  out  that  the  ITU  has  assumed  a  downlead  line  loss  of  1.1  dB  for  low-  VHF,  1.9  dB  for  high-  VHF,  and  3.3  dB  for  UHF,  and  that 
 the  ITU  VHF  line  loss  values  are  virtually  the  same  as  those  assumed  in  the  planning  factor  while  the  ITU  UHF  value  is  lower.  161  In  addition,  dLR  provides  the  following  table  of  cable  specifications  for  three 
 different  cable  manufacturers,  as  shown  in  Table  7:  162 


 Specifications  from  Manufacturers  of  Coaxial  Cable  (75  ohm)  Frequency  Manufacturer  Cable  Type  and 
 Model  Attenuation  (dB/  100  ft)  Attenuation  (db/  50  ft)  Belden  RG  6/  U 
 Model  9116  1.71  0.86  Channel  Master  RG6 
 9533-  500  1.79  0.90  69  MHz  (low  VHF)  Coleman  RG  6/  U 
 Model  992127  1.9  0.95  Belden  RG  6/  U 
 Model  9116  2.73  1.37  Channel  Master  RG6 
 9533-  500  2.89  1.45  194  MHz  (high  VHF)  Coleman  RG  6/  U 
 Model  992127  3.2  1.6  Belden  RG  6/  U 
 Model  9116  5.00  2.50  615  MHz  (UHF)  Channel  Master  RG6 
 9533-  500  5.57  2.79  Table  7.  Coaxial  Cable  Performance  Specifications 


 85.  dLR  points  out  that  in  all  cases  the  attenuation  values  assumed  in  the  downlead  loss  planning  factor  exceed  those  of  available  products.  They  therefore  submit  that  the  current  DTV  planning  factor 
 values  use  conservative  estimates  of  transmission  line  loss.  Based  on  similar  information,  the  NAB  states 
 160  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  4  and  7-  8;  Network  Affiliates  comments  at  31  and 
 App.  (Engineering  Statement  of  Jules  Cohen)  at  4;  and  NAB  comments  at  23-  24  and  Att.  1  (Engineering  Statement  of  MSW)  at  18-  19. 


 161  Network  Affiliates  comments  at  31  and  n.  88  (citing  Draft  Revision  of  Recommendation  ITU-  R  BT.  1368-  4  at 
 Table  13). 
 162  MSTV  comments,  Att.  (Engineering  Statement  of  dLR)  at  7-  8  (Table  4). 
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 that  it  is  reasonable  to  assume  that  consumer  downlead  losses  will  be  no  greater,  and  often  less  than,  those  specified  in  the  DTV  downlead-  loss  planning  factor.  MSW  indicates  that  the  most  expensive  RG  6  or 
 RG  59  cable  costs  about  $25  for  the  typical  50  foot  length  assumed  in  the  planning  factor. 
 86.  In  reply  comments,  EchoStar  and  H&  E  argue  that  it  is  not  realistic  to  assume  that  most  consumers  will  use  RG  6  cable  and  that  a  number  of  other  sources  of  loss,  including  baluns  (matching 


 transformers),  splitters,  and  impedance  mismatch  are  not  accounted  for  at  all.  163  They  state  that  it  is  not  necessarily  realistic  to  assume  that  consumers  will  use  RG-  6  cable  and  that  budget  conscious  consumers 
 may  favor  a  less  expensive  alternative  that  subjects  TV  signals  to  greater  attenuation.  H&  E  argues  that  loss  from  baluns  used  to  connect  300  ohm  antennas  to  75  ohm  cabling  results  in  loss  of  0.6  dB  at  low 
 VHF,  1.5  dB  at  high  VHF  and  2.5  dB  at  UHF.  It  also  argues  that  the  use  of  splitters  that  divide  signals  for  delivery  to  serve  more  than  one  outlet  will  cause  losses.  H&  E  further  argues  that  downlead 
 attenuation  will  increase  with  the  age  of  the  cable.  MSW  counters  that  any  significant  losses  from  impedance  mismatching  or  baluns  can  be  corrected  by  use  of  a  mast-  mounted  low-  noise  pre-  amplifier.  164 
 They  state  that  the  low-  noise  pre-  amplifier  would  isolate  the  antenna  impedance  from  that  of  the  downlead  cable  and  the  DTV  tuner  impedance  and  also  provide  an  output  impedance  much  closer  to  the 
 75  ohm  cable  impedance.  In  their  reply  comments,  the  Network  Affiliates  state  that  while  it  is  true  that  the  DTV  planning  factors  do  not  account  for  impedance  mismatch  between  the  antenna  and  the  receiver 
 front  end,  EchoStars  claim  that  the  Voltage  Standing  Wave  Ratio  (VSWR)  on  downleads  exceeds  2:  1  and  therefore  results  in  an  impedance  mismatch  loss  of  3  dB  is  not  based  on  empirical  studies  of 
 consumer  equipment.  The  Network  Affiliates  submit  that  a  study  by  Schnelle  and  Wetmore  concluded  that  the  results  of  tests  conducted  on  professional  grade  antennas  show  that  it  is  possible  for  antennas  to 
 have  low  return  and  mismatch  loss.  165  That  report  concludes  that  it  is  therefore  reasonable  to  conclude  that  consumer-  grade  antennas  with  good  impedance  matching  capabilities  are  feasible. 


 87.  Based  on  the  record  summarized  above,  we  conclude  that  the  current  DTV  downlead  loss  planning  factor  values  continue  to  provide  a  conservative  estimate  of  the  attenuation  a  received  signal  will 
 experience  between  the  antenna  and  receiver.  While  we  recognize  that  there  are  additional  sources  of  loss  that  could  reduce  the  signal  level  that  arrives  at  a  viewers  receiver,  those  sources  are  not  likely  to  be 
 present  in  a  typical  installation  and  could  be  addressed  by  using  better  cable  or  a  pre-  amplifier  at  any  individual  locations  where  those  sources  might  pose  a  problem  for  DTV  reception.  We  note  that  options 
 for  achieving  the  level  of  performance  specified  in  the  downlead  loss  planning  factor  are  readily  available  at  reasonable  cost.  We  also  understand  that  in  some  cases,  lower  cost  downlead  cabling  with  greater 
 attenuation  may  be  used  by  consumers.  In  this  regard,  we  observe  that  in  many  instances  the  available  DTV  signals  will  be  at  levels  that  such  cabling  will  provide  satisfactory  service.  But  these  considerations 
 do  not  alter  the  fact  that  cabling  that  meets  and  indeed  exceeds  the  performance  levels  assumed  in  the  planning  factors  is  readily  available  at  reasonable  prices.  Further,  if  the  performance  of  cabling  decreases 
 with  age  it  can  and  should  be  replaced  in  the  same  manner  as  any  other  component  whose  performance  deteriorates  or  fails  over  time.  We  find  that  any  losses  from  use  of  baluns  would  generally  be  of  levels 
 low  enough  to  be  compensated  for  by  the  margin  present  in  the  conservative  planning  factor  values  for  downlead  loss  and  antenna  gain.  Similarly,  impedance  mismatch  has  not  generally  been  a  problem  for 
 television  reception  and,  as  indicated  by  MSW,  there  are  solutions  available  if  it  were  to  be  so  in  specific  cases.  We  reject  EchoStar  and  H&  Es  argument  that  splitter  loss  should  be  included  in  the  planning 
 factors.  The  issue  of  whether  sufficient  signal  strength  is  present  for  over-  the-  air  rooftop  reception  is 
 163  EchoStar  reply  comments  at  14-  15  and  Att.  A  (Engineering  Reply  Statement  of  H&  E)  at  2-  3. 
 164  NAB  reply  comments,  Att.  (Engineering  Reply  Statement  of  MSW)  14-  15. 
 165  See  D.  Schnelle  and  R.  E.  Wetmore,  Evaluation  of  Antenna  and  Receiver  Mismatch  Effects  on  DTV 
 Reception,"  48  IEEE  Trans.  on  Broadcasting  365,  369  (Dec.  2002). 
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 independent  of  a  households  choice  to  use  splitters  to  distribute  signals  to  multiple  TV  sets  within  the  home.  In  any  event,  no  loss  splitters,  i.  e.,  distribution  splitters,  the  use  of  which  does  not  result  in  any 
 splitter  loss,  are  readily  and  inexpensively  available.  Accordingly,  we  conclude  that  the  current  downlead  loss  planning  factor  values  remain  appropriate  and  recommend  that  these  values  not  be  changed. 


 88.  Time  and  Location  Variability.  The  field  strength  of  digital  television  signals,  like  that  of  other  radiofrequency  signals,  varies  by  time  and  location.  That  is,  DTV  signal  strength  will  vary  over 
 time  at  the  same  location  and  will  also  vary  from  location  to  location.  These  variations  of  field  strength  with  time  and  location  are  incorporated  into  the  DTV  planning  model  through  use  of  the  F(  50,90)  field 
 strength  curves  to  define  a  DTV  stations  noise-  limited  contour.  As  indicated  above,  the  F(  50,  90)  level  of  service  means  that  at  the  edge  of  a  stations  noise-  limited  contour,  50%  or  more  of  the  locations  can  be 
 expected  to  receive  a  signal  that  exceeds  the  field  strength  standards  at  least  90%  of  the  time.  It  is  possible  to  adjust  these  percentages  by  incrementing  the  field  strength  values  upwards  or  downwards  to 
 reflect  a  desired  level  of  signal  availability.  In  the  planning  factors,  the  values  for  adjustments  to  provide  different  levels  of  time  and  location  availability  were  set  to  zero.  166 


 89.  In  their  comments  in  the  Inquiry,  EchoStar  and  H&  E  argue  that  the  time  variability  assumption  that  a  signal  is  available  at  least  90%  of  the  time  means  that  households  predicted  to  be  served 
 may  not  actually  have  digital  TV  service  for  up  to  five  weeks  of  the  year.  167  They  argue  that  an  increase  in  temporal  reliability  to  99%  or  better  would  be  prudent  until  there  is  greater  experience  with  consumer 
 reception  of  DTV  signals.  H&  E  submits  that  it  collected  temporal  data  on  the  amplitudes  of  fourteen  DTV  signals  that  could  be  received  at  its  Sonoma,  California  offices.  It  states  that  it  found  that  variation 
 in  signal  strength  around  the  median  for  six  of  the  stations  to  be  about  3.5  dB  and  4.9  dB  for  90%  probability  at  high  VHF  and  UHF,  respectively.  It  argues  that  these  values  must  be  added  to  the  DTV 
 signal  strength  standard  to  achieve  90%  and  99%  reliability  of  signal  availability  respectively.  H&  E  states  that  its  data  also  show  that  4.7  dB  and  17.5  dB  would  need  to  be  added  to  the  high  VHF  and  UHF 
 signal  strength  standards  to  increase  to  the  99%  probability  level. 
 90.  In  their  reply  comments,  MSW,  the  NAB  and  the  Network  Affiliates  contend  that  EchoStar  and  H&  Es  claim  that  90%  reliability  means  that  a  viewer  will  not  receive  a  DTV  picture  for  five  weeks  a 


 year  does  not  make  sense.  168  The  Network  Affiliates  state  that  the  statistical  nature  of  the  probability  function  means  that  any  dips  below  the  digital  signal  strength  threshold  will  be  randomly  spaced  over 
 very  long  time  periods  and  thus  have  no  meaning  in  the  sense  of  a  consecutive  time  period.  MSW,  the  NAB,  and  the  Network  Affiliates  argue  that  it  would  be  unfair  to  broadcasters  to  change  the  statistical 
 definition  of  DTV  service  at  this  stage  of  the  transition  and  that  a  change  to  99%  probability  would  greatly  shrink  local  service  areas.  The  Network  Affiliates  also  argue  that  H&  Es  data  collection  is  flawed 
 in  that  H&  E  does  not  explain  its  methodology  or  its  reasons  for  reporting  data  for  only  six  of  the  fourteen  stations  it  studied.  In  its  reply  statement,  MSW  submits  that  the  results  of  the  daytime  field  strength 
 measurements  taken  by  H&  E  ignore  the  fact  that  signal  strength  measurements  taken  during  the  daytime 


 166  In  the  case  of  analog  TV  service,  the  planning  factors  include  adjustments  to  the  time  variability  factors  in 
 order  to  provide  for  service  at  50%  of  locations  90%  of  the  time.  Those  values  add  6  dB  at  low  VHF,  5  dB  at  high  VHF,  and  4  dB  at  UHF  to  the  F(  50,  50)  contour  values  to  define  the  analog  Grade  B  contour  values.  The  analog 


 location  variability  factors  were  set  at  zero.  This  adjustment  was  not  needed  for  DTV  signals  as  the  signal  strength  standards  were  based  on  the  F(  50,  90)  levels  of  signal  availability  rather  than  the  F(  50,  50)  levels. 


 167  EchoStar  comments  at  9  and  Att.  A  (Engineering  Statement  of  H&  E)  at  6-  7. 
 168  NAB  reply  comments  at  7-  8  and  Att.  (Reply  Engineering  Statement  of  MSW)  at  10;  Network  Affiliates  reply 
 comments  at  7-  8. 
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 will  be  lower  than  at  night  when  the  majority  of  television  viewing  occurs.  169  It  notes  that  the  original  TASO  studies  in  the  late  1950s,  as  reported  in  FCC  Report  No.  R-  6602  and  which  provided  the  basis  for 
 the  current  FCC  statistical  propagation  curves  in  Section  73.  699  of  the  rules,  were  meticulously  determined  from  testing  and  evaluation  over  a  three  year  period.  170  MSW  states  that  most  of  the  TASO 
 data  was  collected  over  a  period  of  at  least  six  months  and  sometimes  longer  than  two  years,  and  from  a  multitude  of  locations.  It  therefore  argues  that  a  measurement  program  such  as  that  conducted  by  H&  E, 
 consisting  of  only  six  paths  taken  over  a  two-  week  period,  is  not  statistically  valid  and  has  little  probative  value,  particularly  when  additional  data  was  collected  but  not  reported.  MSW  further  submits  that, 
 according  to  FCC  Report  No.  R-  6602,  signal  strength  for  UHF  signals  are  roughly  2-  3  dB  lower  during  the  daytime,  depending  on  path  distance.  As  a  result,  MSW  reasons  that  signal  strength  measurements 
 during  the  daytime  are  likely  to  be  below  the  median  over  time. 
 91.  We  do  not  find  persuasive  reasons  in  EchoStars  and  H&  Es  submissions  for  changing  the  DTV  time  variability  planning  factor  value.  The  time  variability  value  is  an  important  factor  in 


 determining  the  area  served  by  a  television  station  and  the  amount  of  power  needed  to  cover  a  planned  service  area.  We  believe  that  this  value  should  not  be  changed  in  the  absence  of  a  strong  indication  that 
 its  use  would  be  inconsistent  with  our  DTV  service  model  and  channel  allotment  plan.  In  this  regard,  we  note  that  radiofrequency  signal  propagation  is  always  statistical  in  nature  and  that  the  power  and/  or 
 antenna  height  needed  to  approach  100%  reliability  increases  in  a  non-  linear  manner.  As  indicated  by  MSW,  the  NAB,  and  the  Network  Affiliates,  changing  the  time  variability  factor  values  to  99%  reliability 
 at  this  stage  of  the  transition  would  greatly  shrink  local  DTV  service  areas.  The  current  values  were  established  based  on  an  industry-  Government  consensus  that  relied  on  the  traditional  TV  service  model 
 that  worked  well  for  analog  TV  service  (the  analog  field  strength  values  are  based  on  the  F(  50,  50)  service  level  with  an  augmentation  to  provide  F(  50,  90)  reliability).  We  also  observe,  as  pointed  out  by 
 MSW  in  their  reply  filing,  that  the  assumed  10%  reduction  in  service  availability  occurs  at  the  outermost  limit  of  a  stations  service  area;  it  is  not  the  typical  figure  for  time  reliability  across  a  stations  entire 
 service  area.  As  the  distance  to  a  stations  transmitter  decreases,  the  time  availability  figure  increases.  Households  at  the  edge  of  a  stations  service  area  can  also  improve  their  reception  (and  thereby  reduce  or 
 eliminate  periods  when  the  stations  signal  is  not  available)  by  mounting  their  antenna  higher,  using  a  higher  gain  antennas,  or  using  low-  noise  pre-  amplifiers  at  their  antenna. 


 92.  We  find  that  EchoStars  and  H&  Es  argument  that  the  F(  50,90)  values  result  in  a  loss  of  DTV  service  reception  for  more  than  five  weeks  a  year  ignores  the  fact  that  any  actual  interruptions  of  service 
 tend  to  occur  for  short  periods  in  a  non-  consecutive  manner.  There  also  appear  to  be  serious  methodological  shortcomings  in  the  data  collection  exercise  conducted  by  H&  E,  in  that  it  only  examined 
 daytime  conditions  for  a  short  period  and  for  a  single  location.  Moreover,  we  see  no  theoretical  justification  for  increasing  the  signal  strength  standard  by  adding  a  reliability  factor  amount  equal  to  the 
 variation  in  DTV  signal  strength  measured  over  time.  Considering  all  of  the  information  on  this  issue,  we  are  not  persuaded  that  changes  to  the  time  variability  planning  factor  values  are  warranted.  In  addition, 
 no  commenting  party  suggested  changing  the  location  variability  factor  and  we  know  of  no  considerations  that  would  lead  us  to  recommend  changing  the  current  zero  values  for  this  factor. 


 93.  Dipole  Factor.  The  dipole  factor  expresses  the  quantitative  relationship  between  the  radiofrequency  power  received  by  a  half-  wave  dipole  antenna  and  the  electrical  energy  that  is  present  at 
 the  terminals  of  that  antenna.  This  relationship  is  a  function  of  the  laws  of  physics.  Essentially  the  dipole  factor  provides  for  the  conversion  of  radiofrequency  power  to  electrical  power.  In  the  DTV  planning 
 factors,  the  dipole  factor  is  expressed  in  logarithmic  form  as  the  relationship  between  radiofrequency 
 169  NAB  reply  comments,  Att.  (Reply  Engineering  Statement  of  MSW)  at  9; 


 170  The  FCC  propagation  curves  are  set  forth  in  Section  73.  699  of  the  Commissions  rules,  47  C.  F.  R.    73.  699. 
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 electric  field  strength  and  voltage,  assuming  a  75-  ohm  load.  As  indicated  above,  the  DTV  dipole  factor  values  are  -118.8  dBm,  -120.8  dBm,  and  -130.  8  dBm  for  low  VHF,  high  VHF,  and  UHF,  respectively. 
 94.  In  their  comments  in  the  Inquiry,  the  Network  Affiliates  observe  that  the  dipole  factor  is  dependent  on  frequency  and  that  the  planning  factors  use  a  geometric  mean  frequency  of  a  UHF  band 
 extending  from  470  MHz  to  806  MHz  (channels  14-  69).  171  They  argue  that  because  the  core  DTV  channels  extend  only  to  channel  51,  rather  than  69,  the  dipole  factor  for  the  UHF  band  should  be 
 recalculated  on  the  basis  of  the  geometric  mean  frequency  of  the  UHF  band  extending  from  470  MHz  to  698  MHz  (channels  14-  51).  The  Network  Affiliates  state  that  the  geometric  mean  frequency  of  the  core 
 DTV  UHF  band  is  573  MHz,  which  results  in  a  dipole  factor  of  -130.2  dB,  or  0.6  dB  lower  than  the  current  UHF  dipole  planning  factor  value.  The  effect  of  such  a  change  would  be  to  reduce  the  field  signal 
 strength  level  needed  to  receive  UHF  DTV  signals  by  0.6  dB,  to  83.4  dBm. 
 95.  While  the  geometric  frequency  of  the  UHF  band  will  indeed  change  from  615  MHz  to  573  MHz  at  the  end  of  the  transition  when  all  UHF  DTV  stations  will  operate  in  the  channels  14-  51  core 


 spectrum,  as  indicated  by  the  Network  Affiliates,  we  do  not  believe  that  a  change  in  the  UHF  dipole  planning  factor  value  is  warranted.  Initially,  we  note  that  the  planning  factors  specify  a  single  dipole 
 factor  value  for  the  UHF  band  and  additional  single  values  for  the  low  VHF  and  high  VHF  bands.  Reducing  the  UHF  dipole  planning  factor  value  would  have  the  effect  of  reducing  the  minimum  signal 
 strength  accepted  as  needed  to  receive  service  and  thereby  increase  the  geographic  areas  served  by  stations.  The  true  dipole  values  are  specific  to  each  individual  channel,  as  the  conversion  factor  from 
 electromagnetic  energy  to  electric  energy  through  an  antenna  varies  with  frequency.  Thus,  the  planning  factor  dipole  values  for  each  channel  range  are  only  approximations  of  the  actual  dipole  values  for  each 
 channel.  We  note  that  unlike  the  planning  factors,  the  Longley-  Rice  Model  in  OET  Bulletin  No.  69  includes  a  dipole  modification  factor  that  is  added  to  the  planning  factor  value  so  that  DTV  service  area 
 computations  within  a  stations  noise-  limited  contour  are  made  using  the  true  dipole  factor.  172  Thus,  modification  of  the  dipole  factor  to  reflect  the  geometric  mean  frequency  of  the  core  spectrum  would  not 
 have  any  effect  on  the  actual  service  areas  of  individual  DTV  stations,  because  nothing  in  the  physical  operation  of  the  stations  would  be  changed.  Given  that  the  difference  in  the  current  UHF  dipole  factor 
 and  the  dipole  factor  for  the  core  spectrum  UHF  channels  is  only  .6  dB  and  the  fact  that  changing  this  planning  factor  would  not  actually  affect  the  minimum  threshold  level  of  signal  needed  to  receive 
 individual  stations,  we  find  that  this  planning  factor  should  not  be  changed.  We  conclude  that  the  interests  of  maintaining  stability  in  the  service  areas  of  TV  stations  outweigh  the  benefits  of  providing  a 
 small  apparent  reduction  in  the  level  of  signal  needed  to  receive  UHF  DTV  stations.  173 


 171  Network  Affiliates  comments  at  16. 
 172  See  OET  Bulletin  No.  69  at  3-  4. 
 173  We  note  that  Jules  Cohen,  the  consulting  engineer  for  Network  Affiliates,  appears  to  agree  with  this 
 conclusion.  See  Network  Affiliates  comments,  Appendix  (Engineering  Statement  of  Jules  Cohen)  at  5  (  in  light  of  an  absence  of  need  to  change  other  [planning  factors],  the  dipole  factor  is  not  proposed  to  be  changed). 
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 4.  Additional  Considerations 
 96.  In  response  to  Section  339(  c)(  1)(  B)(  vi)  we  also  considered  whether  to  account  for  factors  such  as  building  loss,  external  interference  sources,  or  undesired  signals  from  both  digital  television  and 


 analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets,  foliage,  and  man-made  clutter  in  the  digital  television  field  strength  standards.  Our  assessment  of  building  loss  in  the  case 
 of  indoor  antennas  as  a  potential  factor  in  the  digital  television  field  strength  standards  are  set  forth  in  the  discussion  above  concerning  antenna  gain,  orientation,  and  placement.  There,  we  observe  that  building 
 losses  are  dependent  on  the  materials  with  which  the  building  is  constructed  and  the  location  of  an  antenna  within  the  building.  Because  of  these  variabilities,  we  conclude  that  it  would  be  impractical  to 
 establish  an  indoor  digital  television  field  strength  standard.  We  also  observe  that  while  the  location  of  buildings  with  respect  to  outdoor  antennas  may  have  an  effect  on  the  signal  strength  that  reaches  an 
 outdoor  antenna,  in  most  cases  there  will  be  many  paths  by  which  a  digital  television  signal  can  generally  be  expected  to  reach  that  antenna  despite  the  presence  of  buildings,  other  man-  made  clutter,  and 
 vegetation  in  the  signal  path.  We  therefore  conclude  that  building  loss  should  not  be  considered  in  the  digital  television  field  strength  standard.  On  the  other  hand,  blockage  from  buildings,  other  man-  made 
 clutter  and  vegetation  is  likely  to  be  a  factor  in  the  digital  television  signal  strength  that  is  available  at  individual  locations.  These  elements  were  previously  factored  into  the  predictive  model  used  for 
 determining  analog  television  field  strengths  at  individual  locations,  and  we  find  that  it  would  be  appropriate  to  include  those  same  factors  into  a  predictive  model  for  determining  digital  television  field 
 strengths  at  individual  locations.  That  issue  is  discussed  in  the  section  below  on  the  digital  television  predictive  model. 


 97.  Looking  at  the  performance  of  DTV  receivers  in  the  presence  of  interfering  signals,  we  observe  that  in  general  a  radio  receivers  immunity  to  interference  is  dependent  on  a  number  of  factors  in 
 its  technical  design  and,  in  addition,  on  the  characteristics  of  the  signals  it  is  designed  to  receive.  These  factors  may  be  closely  related  and  possibly  interdependent,  and  a  receivers  performance  on  one  factor 
 may  often  affect  its  performance  on  others.  The  factors  determining  receiver  immunity  performance  generally  include  selectivity,  sensitivity,  dynamic  range,  automatic  RF  gain  control,  shielding,  modulation 
 method,  and  signal  processing.  Receiver  selectivity  is  the  ability  to  isolate  and  acquire  the  desired  signal  from  among  all  of  the  undesired  signals  that  may  be  present  on  other  channels.  Sensitivity  is  the  measure 
 of  a  receivers  ability  to  receive  signals  of  low  strength.  Greater  sensitivity  means  a  receiver  can  pick  up  weaker  signals.  174  Dynamic  range  is  the  range  of  the  highest  and  lowest  received  signal  strength  levels 
 over  which  the  receiver  can  satisfactorily  operate.  The  upper  side  of  a  receivers  dynamic  range  determines  how  strong  a  received  signal  can  be  before  failure  due  to  overloading  occurs.  Automatic  RF 
 gain  control  allows  a  receiver  to  adjust  the  level  of  a  received  signal  as  it  appears  at  the  units  signal  processing  and  demodulation  sections. 


 98.  In  the  Inquiry,  we  noted  that  many  factors  can  affect  the  reception  of  radio  frequency  signals  and  the  ability  of  a  receiver  to  resolve  these  signals  and  produce  a  picture.  175  Most  notably,  interference 
 from  both  co-  channel  and  adjacent  channel  TV  transmitters  could  cause  interference  to  the  desired  signal.  Selectivity  is  a  central  factor  in  the  control  of  adjacent  channel  interference.  176  However,  we  also  noted 


 174  Greater  sensitivity  can  also  result  in  reception  of  unwanted  signals  at  low  levels  that  then  must  be  eliminated  or 
 attenuated  by  the  selectivity  characteristics  of  the  receiver. 
 175  Inquiry,  supra  note  22,  at    19. 


 176  There  are  several  ways  to  describe  the  selectivity  of  a  radio  receiver.  One  way  is  to  simply  give  the  bandwidth 
 of  the  receiver  over  which  its  response  level  is  within  3  dB  of  its  response  level  at  the  center  frequency  of  the  desired  signal.  This  measure  is  often  termed  the  bandwidth  over  the  -3db  points.  This  bandwidth,  however,  is 


 not  necessarily  a  good  means  of  determining  how  well  the  receiver  will  reject  unwanted  frequencies. 
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 that  different  receiver  designs  may  account  for  the  differing  abilities  of  receivers  to  reject  greater  or  lesser  amounts  of  interference.  We  requested  comment  on  the  interference  rejection  capabilities  of  digital  TV 
 receivers  and  satellite  set-  top-  boxes  with  built-  in  off-  air  receivers. 
 99.  In  their  comments  responding  to  our  Inquiry,  ATI  notes  that  in  2003  the  Commission  suggested  that  the  ATSC  develop  voluntary  standards  for  DTV  receiver  performance  177  and  that  in 


 response  the  ATSC  developed  such  standards  and  published  them  in  its  A/  74  Recommended  Practice:  Receiver  Performance  Guidelines  (A/  74  Recommended  Practice).  178  The  ATSC  recommended  DTV 
 receiver  performance  standards  were  developed  by  industry  parties  representing  broadcasters,  consumer  electronics  manufacturers,  consumers,  and  others.  These  standards  address  DTV  receiver  performance  in 
 the  areas  of  sensitivity,  multisignal  overload,  phase  noise,  selectivity,  multipath,  antenna  interface  and  consumer  interface.  ATI  recommends  that  the  Commission  adopt  the  ATSC  A/  74  Recommended 
 Practice  for  receiver  performance  because  it  reflects  this  cross-  industry  agreement  and  provides  the  most  appropriate  and  accepted  parameters  for  evaluating  receiver  performance. 


 100.  H&  E  submits  that  two  respected  engineers  have  expressed  concern  about  interference  from  adjacent  channel  intermodulation  interference  sources.  179  It  further  states  that  it  is  aware  of  several 
 failures  of  DTV  reception  that  are  attributable  to  image  interference  from  strong  undesired  signals  and  notes  that  image  interference  (typically  resulting  from  signals  seven  or  eight  channels  above  or  below  the 
 desired  channel)  is  not  currently  addressed  by  the  Commissions  DTV  allotment  standards.  H&  E  states  that  while  there  currently  is  not  enough  information  to  assess  typical  receiver  performance  with  regard  to 
 image  interference,  the  existing  protection  ratios  as  documented  in  OET  Bulletin  No.  69  might  be  presumptively  used  to  determine  the  presence  of  interference  and  provide  reasonable  goals  for  DTV 
 receiver  designs. 
 101.  We  observe  that  a  receivers  ability  to  provide  service  in  the  presence  of  interfering  signals  is  not  relevant  to  the  field  strength  needed  to  provide  service.  While  the  presence  of  other  signals 


 on  the  same  or  adjacent  channels  does  have  the  potential  for  causing  interference  that  can  cause  loss  of  service,  the  effects  of  other  signals  are  a  separate  matter  from  the  basic  functioning  of  a  receiver  in  an 
 interference-  free  environment  that  forms  the  basis  for  the  Commissions  field  strength  standards.  In  general,  interference  caused  by  the  presence  of  a  signal  in  the  same  channel  as  the  desired  channel  (co-channel 
 interference)  is  a  problem  that  cannot  be  addressed  by  receiver  improvements  and  must  be  addressed  by  avoidance  of  signal  overlap.  Interference  from  signals  one  or  more  channels  removed  from 
 the  desired  channel  (adjacent  channel  interference),  however,  can  be  addressed  by  designing  receivers  to  be  more  selective  and  using  antennas  that  provide  discrimination  against  unwanted  signals  through 
 directivity. 


 Consequently,  it  is  common  to  give  the  receiver  bandwidth  at  two  levels  of  attenuation;  for  example,  -6dB  and  -60  dB.  The  ratio  of  these  two  bandwidths  is  called  the  shape  factor.  Ideally,  the  two  bandwidths  would  be  equal 
 and  the  shape  factor  would  be  one.  However,  this  value  is  very  difficult  to  achieve  in  a  practical  circuit. 
 177  See  Interference  Immunity  Performance  Specifications  for  Radio  Receivers;  Review  of  the  Commissions 
 Rules  and  Policies  Affecting  the  Conversion  to  Digital  Television,  Notice  of  Inquiry  in  ET  Docket  No.  03-  65  and  MM  Docket  No.  00-  39,  18  FCC  Rcd  6039  (2003). 


 178  See  A/  74  Recommended  Practice:  Receiver  Performance  Guidelines,  Advanced  Television  Systems 
 Committee,  Inc.,  June  18,  2004. 
 179  H&  E  citing  Oded  Bendov,  Interference  to  DTV  Reception  by  First  Adjacent  Channels,  IEEE  Trans.  on 
 Broadcasting,  Vol.  51,  No.  1,  March  2005  and  Charles  W.  Rhodes,  Interference  between  Television  Signals  Due  to  Intermodulation  in  Receiver  Front-  Ends,  IEEE  Trans.  on  Broadcasting,  Vol.  51,  No.  1,  March  2005. 
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 102.  As  a  general  matter,  the  Commission  has  traditionally  refrained  from  attempting  to  regulate  the  ability  of  receivers  to  provide  service  in  the  presence  of  adjacent  channels.  Instead,  it  has 
 relied  on  market  forces  to  direct  manufacturers  to  produce  television  sets  that  provide  satisfactory  service  in  the  RF  environment  allowed  by  the  Commissions  rules.  In  this  regard,  the  rules  provide  engineering 
 and  inter-  station  spacing  standards  that  limit  the  signal  strength  of  co-  channel  and  adjacent  channel  signals  that  are  present  in  a  licensed  stations  service  area.  Manufacturers  are  then  free  to  build  receivers 
 to  whatever  levels  of  performance  they  choose  with  respect  to  selectivity  and  other  performance  characteristics.  Market  forces  provide  incentives  for  manufacturers  to  design  products  that  will  operate 
 within  the  RF  environment  that  may  exist  in  an  area.  If  a  receiver  does  not  provide  service  in  that  environment,  a  consumer  would  very  likely  return  it  to  the  place  of  purchase  thereby  providing  economic 
 feedback  to  the  manufacturer. 
 103.  Over  the  years,  this  approach  has  worked  very  well  and  the  Commission  has  not  found  it  necessary  to  establish  performance  standards  for  TV  receivers  to  avoid  interference.  For  example,  most 


 recently  in  the  1999-  2000  time  frame  it  became  apparent  that  the  performance  of  the  active  equalizer  function  of  digital  television  receivers  that  provides  immunity  to  multipath  was  not  adequate  in  the  early 
 models  of  receivers.  180  Manufacturers  responded  to  this  performance  problem  by  improving  the  performance  of  the  adaptive  equalizer  function.  That  improvement  effort,  which  is  still  on-  going,  has 
 now  produced  the  fifth  generation  DTV  receivers  that  are  able  to  provide  satisfactory  performance  under  most  conditions  of  multipath.  We  continue  to  believe  that  reliance  on  market  forces  is  the  most 
 appropriate  approach  for  ensuring  that  DTV  receivers  perform  satisfactorily  with  regard  to  their  ability  to  handle  interfering  signals.  That  approach  allows  manufacturers  the  freedom  to  design  products  that  meet 
 a  variety  of  consumer  needs  and  also  to  implement  changes  that  may  be  needed  to  implement  new  components,  address  a  new  understanding  of  the  television  signal  environment,  or  meet  changes  in  the 
 consumer  market.  While  we  understand  that  a  few  parties  may  be  concerned  about  the  interference  immunity  performance  of  DTV  receivers,  the  DTV  receiver  products  currently  on  the  market  generally 
 appear  to  be  performing  satisfactorily  in  rejecting  interference.  In  this  regard,  we  have  not  seen  any  obvious  problems  with  the  receivers  on  the  market  now  failing  to  provide  service  because  of  interference. 
 Thus,  it  appears  that  market  forces  are  adequately  providing  for  interference  immunity. 
 104.  We  do  believe  that  the  ATSC  A/  74  Recommended  Practice  provides  a  strong  benchmark  for  the  performance  capabilities.  The  standards  in  this  document  provide  clear  performance  targets  for 


 the  development  of  DTV  receivers  that  provide  quality  performance  within  an  economically  feasible  cost  structure.  While  we  strongly  encourage  manufacturers  to  consider  and  adhere  to  the  performance 
 standards  in  A/  74  Recommended  Practice,  we  do  not  find  any  compelling  reason  to  make  compliance  with  those  or  any  other  DTV  receiver  performance  standards  mandatory  to  ensure  that  television  service 
 is  not  affected  by  interference  at  this  time.  Accordingly,  we  do  not  recommend  that  Congress  take  any  action  with  regard  to  the  digital  television  field  strength  standards  or  otherwise  adjust  the  methods  for 
 determining  whether  it  is  possible  to  receive  television  signals  at  a  location  to  account  for  receiver  interference  performance. 


 C.  Alternative  Standards  to  Field  Strength 
 105.  In  Section  339(  c)(  1)(  B)(  iii),  Congress  requested  that  the  Commission  consider  whether  a  standard  should  be  used  other  than  the  presence  of  a  signal  of  a  certain  strength  to  ensure  that  a  household 


 can  receive  a  high-  quality  picture  using  antennas  of  reasonable  cost  and  ease  of  installation.  In  response  to  the  Inquiry,  CEA  states  that  it  believes  that  the  presence  of  a  signal  of  a  certain  strength  is  the  right 


 180  See  Review  of  the  Commissions  Rules  and  Policies  Affecting  the  Conversion  to  Digital  Television,  Report 
 and  Order  and  Further  Notice  of  Proposed  Rule  Making,  16  FCC  Rcd  5946  (2001).  That  decision  also  discusses  the  Commissions  approach  to  regulation  of  television  receiver  performance. 
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 level  of  involvement  of  the  FCC  in  determining  the  availability  of  TV  service.  181  It  states  that  going  beyond  that  approach  would  invite  a  quagmire  of  assessing  reasonableness,  cost  effectiveness,  and  ease  of 
 installation.  The  NAB  similarly  submits  that  field  strength  standards  are  better  than  alternative  approaches  such  as  those  that  would  use  a  picture  quality  test  because  qualitative  tests  involve 
 subjective  judgments.  It  argues  that  because  the  results  of  field  testing  by  experienced  engineers  show  that  objective  signal  strength  is  an  excellent  proxy  for  the  availability  of  a  high-  quality  digital  picture, 
 there  is  no  need  for  such  judgments  to  be  made.  Based  on  our  long  experience  with  radio  services,  we  do  not  believe  that  any  alternative  to  field  strength  standards  would  provide  a  better  indicator  of  whether  a 
 household  can  receive  service.  In  this  regard,  we  note  that  the  DTV  field  strength  standards  in  fact  incorporate  a  large  number  of  considerations,  as  evidenced  by  the  technical  criteria  represented  in  the 
 planning  factors.  We  believe  that  the  numerous  elements  that  affect  reception  of  digital  television  service  are  adequately  and  appropriately  included  in  the  standard  through  the  DTV  planning  factors. 
 Accordingly,  we  recommend  that  the  current  plan  of  field  strength  values  and  their  specification  remain  the  standards  for  determining  whether  digital  television  signals  can  be  received.  We  further  recommend 
 that  the  Congress  continue  to  allow  the  Commission  to  modify  or  replace  those  standards  through  the  rule  making  process  as  may  be  necessary.  We  believe  the  flexibility  of  that  process  provides  an  adequate 
 means  for  both  identifying  when  and  if  changes  are  necessary  and  for  developing  appropriate  revisions. 
 D.  Summary  Field  Strength  Standards  Recommendations 
 106.  From  the  above  discussion,  we  observe  that  households  face  a  wide  range  of  situations  in  receiving  over-  the-  air  digital  television  service,  just  as  they  always  have  with  analog  television  service. 


 In  the  variability  of  receive  sites  there  are  some  cases,  i.  e.,  where  a  stations  signal  is  particularly  weak,  in  which  a  household  that  is  within  a  TV  stations  service  area  may  not  be  able  to  receive  service  using  the 
 typical  TV  reception  system.  In  those  cases  there  are  readily  available  options  to  improve  the  capability  of  the  households  receive  systems  to  obtain  over-  the-  air  service.  In  other  cases,  i.  e.,  where  a  stations 
 signal  is  particularly  strong,  a  household  may  not  need  a  receive  system  with  the  full  capabilities  of  the  typical  receive  system  and,  for  example,  may  be  able  to  use  an  indoor  antenna.  Given  the  ready 
 availability  of  equipment  for  receiving  service  in  locations  with  different  levels  of  available  field  strength  and  the  administrative  efficiency  of  providing  a  simple,  easy  to  understand  and  apply  definition  of  DTV 
 service  area  and  signal  availability,  we  continue  to  believe  that  it  is  appropriate  to  define  digital  television  signal  availability/  service  area  using  field  strength  standards  that  are  specified  on  the  basis  of  a  typical 
 receive  system.  For  the  reasons  indicated  in  this  discussion  above,  we  believe  any  other  approach  that  would  introduce  more  variables  and  complexity  could  lead  to  subjectivity  and  arbitrariness  in  making 
 determinations  of  signal  availability.  We  also  conclude  that  there  is  no  alternative  approach  to  field  strength  standards  that  would  provide  a  more  accurate  measure  of  service  area  and/  or  signal  availability  at 
 individual  locations. 
 107.  The  variability  that  exists  in  receive  conditions  extends  to  the  performance  of  the  specific  elements  of  the  receive  systems  used  by  consumers.  For  example,  a  given  household  may  not  need  to  use 


 a  downlead  that  approaches  50  feet  or  the  antenna  it  uses  may  provide  less  gain  than  that  specified  in  the  planning  factors.  In  the  evaluations  above,  we  balanced  the  variability  of  these  situations.  The  planning 
 factor  values  were  established  as  typical  values  that  could  be  expected  in  a  households  TV  reception  system.  We  also  believe  that  the  planning  factor  values  as  specified  are  in  some  instances,  such  as 
 antenna  gain,  downlead  loss,  and  receiver  noise  figure  somewhat  conservative.  These  values  appear  to  provide  a  few  dB  of  additional  margin  in  the  summation  of  factors  that  determine  the  minimum  signal 
 level  needed  for  service  so  that  the  level  of  signal  that  is  needed  for  service  would  be  a  little  lower.  On  the  other  hand,  certain  other  factors  such  as  downlead  impedance  mismatch,  balun  loss,  and  in  some  cases 


 181  See  CEA  comments  at  3-  4. 
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 IV.  DIGITAL  TELEVISION  FIELD  STRENGTH  MEASUREMENT  PROCEDURES 
 109.  The  Commission  has  standardized  procedures  for  measuring  the  field  strength  of  analog  television  signals  at  individual  locations.  182  Now,  as  we  are  on  the  horizon  of  transitioning  to  digital 
 television,  Congress  has  asked  us  to  consider  whether,  for  evaluating  if  a  household  is  unserved  for  purposes  of  determining  eligibility  to  receive  distant  network  signals  retransmitted  from  a  satellite 
 service,  different  field  strength  measurement  procedures  are  necessary.  183  Specifically,  in  Section  339(  c)(  1)(  B)(  ii)  of  the  Communications  Act,  as  amended  by  the  SHVERA,  Congress  asked  the 
 Commission  to  consider  whether  Section  73.686(  d)  of  the  Commissions  rules  should  be  amended  to  create  different  procedures  for  determining  if  the  requisite  digital  signal  strength  is  present  than  for 
 determining  if  the  requisite  analog  signal  strength  is  present. 
 110.  Currently,  Section  73.686(  d)(  1)(  i)  requires  that  field  strength  measurements  be  made  using  either  a  half  wave  dipole  antenna  that  is  tuned  to  the  stations  visual  carrier  frequency  or  a  gain 


 antenna,  provided  that  the  antenna  factor  for  the  channel  under  test  is  known.  184  In  addition,  the  rules  specify  that  the  intermediate  frequency  (i.  f.)  bandwidth  of  the  measuring  instrumentation  be  at  least  200 
 kilohertz  but  no  more  than  1,000  kilohertz.  185  Measurements  are  to  be  taken  in  five  locations,  preferably  close  to  the  actual  antenna  or  where  one  is  likely  to  be  mounted.  186  In  addition,  the  rules  specify  that  the 
 measurement  antenna  is  to  be  raised  to  a  height  of  6.1  meters  (20  feet)  above  ground  for  one  story  structures  and  9.1  meters  (30  feet)  above  ground  for  two  story  or  taller  structures.  187  Finally,  because  the 
 current  rule  was  written  specifically  to  determine  the  field  strength  of  analog  TV  signals,  the  procedures  specify  that  the  field  strength  measurement  is  to  be  made  on  the  visual  carrier.  188  The  measured  values 
 are  then  to  be  compared  to  the  field  strength  that  defines  the  Grade  B  contour  for  the  station  in  question  to  determine  if  the  measured  location  is  receiving  a  signal  of  sufficient  intensity  for  analog  television 
 reception. 
 111.  In  the  Inquiry,  the  Commission  recognized  that  the  rules  defining  measurement  procedures  for  analog  television  cannot  simply  be  applied  to  digital  television  signals.  189  Thus,  some 


 modifications  are  necessary.  As  described  above,  the  current  measurement  procedure  requires  that  measurements  be  conducted  on  the  visual  carrier.  Digital  television  signals,  however,  do  not  contain  a 
 visual  carrier.  Instead,  all  information    video  and  audio    is  encoded  within  the  bit  stream  that  makes  up  the  entire  signal.  We  stated,  therefore,  that  a  new  rule  would  be  needed  to  deal  with  the  measurement  of 
 digital  television  signals,  at  least  insofar  as  it  relates  to  the  specific  frequency  on  which  to  tune.  190  The  Commission  pointed  out  that  the  digital  television  signal  contains  a  pilot  signal  that  is  used  by  a  receivers 


 182  See  47  C.  F.  R.    73.  686(  d);  see  also,  SHVA  Report  and  Order,  14  FCC  Rcd  2654  at    8. 
 183  47  U.  S.  C.  339(  c)(  1)(  B)(  ii),  as  amended  by  Section  204(  b)  of  the  SHVERA. 
 184  See  47  CFR  73.  686(  d)(  1)(  i). 
 185  See  47  C.  F.  R.    73.  686(  d)(  2)(  i). 
 186  See  47  C.  F.  R.    73.  686(  d)(  1)(  ii). 
 187  See  47  C.  F.  R.    73.  686(  d)(  2)(  iii). 
 188  See  47  C.  F.  R.    73.  686(  d)(  1)(  i)  and  73.  686(  d)(  2)(  i). 
 189  Inquiry,  supra  note  22,  at    13. 
 190  Id. 
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 tuner  to  lock  onto  the  desired  received  signal  and  suggested  that  this  signal  could  be  used  for  measurement  purposes.  191  More  generally,  the  Commission  asked  commenting  parties  to  provide 
 information  on  the  signal  characteristics  to  which  the  measurement  instrumentation  should  be  tuned  (e.  g.,  pilot  signal,  center  of  channel,  etc.).  We  also  noted  that  the  portion  of  the  current  rule  for  determining  if  a 
 household  is  unserved  by  comparing  the  measured  signal  strength  value  to  the  Grade  B  contour  field  strength  is  not  appropriate  for  digital  television  signals.  For  digital  television  stations,  instead  of  a 
 contour  defined  by  Grade  B  signal  intensity,  the  noise-  limited  service  contour,  as  defined  in  Section  73.622(  e)  of  the  Commissions  Rules,  is  used.  192 


 112.  In  addition  to  the  Commissions  request  for  comment  regarding  the  aforementioned  differences  between  analog  and  digital  television  signals,  comment  was  also  sought  on  other  portions  of 
 the  analog  signal  strength  measurement  rule  and  their  applicability  to  digital  television  signals.  We  asked  whether  the  i.  f.  bandwidth  of  the  measurement  equipment  that  is  specified  for  analog  television  signals  is 
 also  appropriate  for  digital  TV  signals.  We  further  requested  comment  on  the  height  that  should  be  specified  for  the  receiving  antenna  equipment  to  measure  outdoor  signals,  and  on  whether  specific 
 procedures  should  be  created  for  measuring  the  availability  of  indoor  signals.  Regarding  indoor  measurements,  we  asked  if  the  Commission  were  to  adopt  such  procedures,  what  criteria  should  be 
 applied  to  determine  whether  an  indoor  or  an  outdoor  measurement  would  be  performed  at  a  specific  location.  Finally,  we  asked  if  there  are  any  other  aspects  of  our  measurement  procedures  that  need  to  be 
 modified  for  the  purpose  of  determining  if  households  are  unserved  by  an  adequate  digital  TV  signal. 
 113.  Congress,  in  SHVERA,  also  requested  that  the  Commission  consider  whether  to  account  for  factors  such  as  building  loss,  external  interference  sources,  or  undesired  signals  from  both  digital 


 television  and  analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets,  foliage,  and  man-  made  clutter.  In  the  Inquiry,  we  requested  that  commenting  parties  provide  information 
 regarding  how  to  account  for  these  factors.  193  We  noted  that  many  factors  can  affect  the  reception  of  radio  frequency  signals  such  as  interference  from  both  co-  channel  and  adjacent  channel  TV  transmitters. 
 We  also  noted  that  other  external  forces  can  affect  the  signal  that  ultimately  reaches  a  TV  receiver.  These  include  natural  and  man-  made  structures  that  lie  between  the  transmitter  and  the  receiver.  We  observed 
 that  these  obstructions  can  affect  a  signal  in  various  ways  such  as  by  attenuating  the  signal  so  that  the  actual  signal  received  is  weaker  than  that  predicted  in  the  absence  of  any  such  obstructions  or  by  creating 
 multipath  interference,  which  occurs  when  a  signal  bounces  off  structures  and  the  main  and  reflected  signals  arrive  at  the  receiver  at  different  times. 


 114.  Inquiry  Record.  NAB  and  the  Network  Affiliates  state  that  existing  methods  for  measuring  field  intensity  at  individual  locations  will,  with  a  few  minor  modifications,  work  well  for 
 digital  signals.  194  Many  of  the  suggested  modifications  are  straightforward  and  are  a  direct  result  of  the  questions  the  Commission  asked.  For  example,  NAB  points  out  that  the  rules  for  digital  television 
 measurements  must  reference  the  appropriate  noise-  limited  field  strength  value  rather  than  the  Grade  B  contour.  195 


 191  The  pilot  signal  is  located  0.31  MHz  inside  the  lower  band  edge  of  the  DTV  channel  and  has  a  power  level  that 
 is  3  dB  lower  than  the  average  power  of  the  DTV  signal. 
 192  47  CFR    73.  622(  e);  see  also  47  CFR    73.  625(  b)  (determining  coverage). 


 193  Inquiry,  supra  note  22,  at    20. 
 194  NAB  comments  at  25;  Network  Affiliates  comments  at  38. 
 195  NAB  comments  at  26. 
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 they  state  that  indoor  testing  would  be  impossible  to  standardize.  204  The  Network  Affiliates  add  that  local  service  would  be  eviscerated  if  the  Commission  was  to  recommend  measuring  signal  strength  indoors  or 
 establishing  an  indoor  standard  that  the  entire  DTV  service  was  never  intended  to  meet.  205  The  NAB  and  the  Network  Affiliates  state  that  this  is  because  the  signal  attenuation  due  to  building  materials  coupled 
 with  the  lower  gain  antenna  would  have  the  effect  of  decreasing  the  service  area  size.  Moreover,  the  Network  Affiliates  state  that  EchoStars  claims  with  respect  to  indoor  antennas  and  building  penetration 
 are  irrelevant  given  that  the  Commission  has  always  assumed  that  homeowners  would  use  an  outdoor  directional  gain  antenna  for  over-  the-  air  reception.  The  NAB  adds  that  EchoStar  does  not  provide  any 
 explanation  for  the  unfairness  of  assuming  that  the  same  household  that  uses  an  outdoor  dish  to  receive  satellite  TV  would  use  an  indoor  antenna  for  over-  the-  air  signals.  206 


 118.  A  second  area  where  EchoStar  believes  the  current  testing  procedures  should  be  modified  is  with  regard  to  antenna  pointing.  The  current  procedure  specifies  that  the  measurement  is  to  be  taken 
 with  the  antenna  oriented  in  the  direction  of  maximum  signal  strength.  EchoStar  claims  that  this  requirement  implicitly  assumes  that  every  household  has  a  rotating  antenna  that  can  be  re-  pointed  to 
 optimize  reception  for  each  local  station,  which  it  contends  is  unrealistic.  207  To  this  point,  it  suggests  that  signal  strength  loss  from  mispointing  should  be  taken  into  account  in  the  measurement  procedures. 
 EchoStar  suggests  further  study  to  determine  the  average  signal  loss  due  to  mispointing  and  submits  that  this  value  should  be  subtracted  from  the  measured  signal  before  comparing  to  the  Commissions 
 signal  strength  standard.  208  It  further  suggests  that  because  only  10-  15%  of  households  have  rotors,  those  that  do  not  may  point  the  antenna  in  a  direction  other  than  the  direction  of  maximum  signal  strength  to 
 achieve  optimum  reception  for  all  stations.  H&  E  argues  that  it  would  make  sense  to  orient  the  measurement  antenna  in  the  same  direction  as  other  antennas  in  the  area.  209 


 119.  The  NAB  and  the  Network  affiliates  disagree  with  EchoStar  on  this  point.  NAB  avers  that  EchoStar  fails  to  explain  why  it  would  be  good  policy  to  assume  an  incorrectly  pointed  antenna  when 
 the  entire  DTV  transition  has  been  premised  on  use  of  a  properly  oriented  antenna.  210  The  NAB  and  the  Network  Affiliates  also  state  that  EchoStar  ignores  obvious  problems  with  their  suggestion  to  point  the 
 measuring  antenna  in  the  direction  of  antennas  at  neighboring  households.  These  include:  1)  neighboring  households  may  have  rotors  and  only  temporarily  point  their  antennas  in  a  certain  direction;  2) 
 neighboring  households  may  have  antennas  that  have  been  abandoned;  3)  there  may  be  no  neighboring  households  with  outdoor  antennas;  and  4)  there  is  no  readily  available  methodology  to  determine  the 
 direction  that  neighboring  households  have  oriented  their  antennas  and  translate  that  into  a  direction  for  orienting  a  test  antenna.  211  NAB  further  points  out  that  in  many  areas  local  installers  can  supply  antennas 
 that  are  non-  rotating,  but  that  point  correctly  at  all  of  the  local  stations  when  installed.  212  They  also  state 
 204  NAB  comments  at  27  and  Att.  1  (Engineering  Statement  of  MSW)  at  22. 


 205  Network  Affiliates  comments  at  39-  40. 
 206  NAB  reply  comments  at  3. 
 207  EchoStar  comments  at  7. 
 208  EchoStar  comments  at  8. 
 209  Id.,  Att.  1  (Engineering  Statement  of  H&  E)  at  4. 
 210  NAB  reply  comments  at  4. 
 211  Network  Affiliates  reply  comments  at  15;  NAB  reply  comments  at  6. 
 212  NAB  reply  comments  at  5. 
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 that  in  83%  of  the  television  markets  where  there  is  a  full  complement  of  major  network  affiliates  (ABC,  NBC,  CBS,  Fox),  the  digital  television  stations  are  co-  located.  213 
 120.  Several  other  suggestions  were  made  by  EchoStar  in  response  to  our  Inquiry  questions  concerning  measurements.  Specifically,  it  recommends  that  testing  include  collection  of  multipath  and 
 other  interference  data  and  that  testing  be  done  over  time  to  account  for  time  variability  of  the  measurement.  On  the  first  point,  EchoStar  states  that  multipath  interference  is  a  more  acute  problem  for 
 digital  television  than  for  analog.  214  It  argues  that  dynamic  multipath,  which  occurs  due  to  signals  bouncing  off  of  moving  objects,  is  difficult  to  account  for,  but  that  static  multipath  interference  can  be 
 measured  and  its  severity  can  be  expressed  as  a  signal  strength  penalty.  EchoStar  states  that  this  penalty  should  be  subtracted  from  the  measured  digital  signal  strength  before  it  is  compared  against  the 
 Commissions  digital  strength  standard.  215  In  addition,  EchoStar  submits  that  field  measurements  should  include  the  collection  of  white  noise  enhancement  values.  216  The  Network  Affiliates  and  the  NAB  both 
 argue  that  such  measurements  and  compensation  are  unnecessary.  They  point  out  that  in  the  past  it  may  have  been  true  that  digital  television  receivers  had  difficulty  with  multipath,  but  that  current  5  th  generation 
 receivers  can  easily  handle  multipath  conditions  that  those  earlier  receivers  could  not  resolve.  The  NAB  also  points  out  that  6  th  generation  receivers  that  will  encompass  further  improvements  will  soon  be 
 available.  217  The  NAB  further  states  that  there  is  no  need  to  account  for  white  noise  enhancement  since  it  only  adds  about  0.2  dB  of  noise  that  is  more  than  made  up  by  factors  that  overestimate  the  available 
 signal  strength  required  and  thereby  make  the  planning  factors  conservative.  It  states  that  these  include  the  fact  that  real  antennas  have  gains  that  exceed  the  planning  factors,  available  coaxial  cables  have  losses 
 less  than  those  assumed,  and  low  noise  amplifiers  are  readily  available. 
 121.  With  regard  to  digital  television  signal  time  variability,  EchoStar  comments  that  the  H&  E  study  shows  significant  variability  over  time  and  that  because  the  Longley-  Rice  predictive  propagation 


 model  is  based  on  empirical  data  about  time  variability,  it  would  be  strange  for  actual  testing  to  ignore  it  completely.  It  therefore  asserts  that  the  testing  procedures  be  modified  to  account  for  variability  in  signal 
 strength  over  time.  EchoStar  suggests  that  this  could  be  done  by  taking  the  specified  cluster  measurements  and  assuming  they  provide  a  median  signal  level  and  then  applying  a  correction  factor  to 
 achieve  90%  time  reliability.  218  The  result  of  such  a  correction  would  be  to  increase  the  minimum  signal  strength  that  defines  digital  television  service.  The  NAB,  in  response,  points  out  that  the  minimum  signal 
 level  that  defines  digital  television  service  is  specified  in  the  statute  and  as  such  any  change  cannot  be  done  by  regulation.  219  As  with  its  response  to  EchoStar  on  multipath,  the  NAB  again  states  that  the 


 213  Id. 
 214  EchoStar  comments  at  5. 
 215  Id.. 
 216  White  noise  enhancement  is  the  increased  noise  added  to  the  system  by  the  equalizer  as  it  attempts  to 
 compensate  for  multipath.  EchoStar  comments,  Att.  A  (Engineering  Statement  of  H&  E)  at  8-  9. 
 217  NAB  reply  comments  at  10-  11;  Network  Affiliates  reply  comments  at  10. 


 218  EchoStar  comments  at  8.  It  states  that  a  correction  factor  can  be  derived  from  the  F(  50.  50)  and 
 F(  50.  90)  curves  by  using  the  difference  in  values  given  the  distance  from  the  transmitter. 
 219  NAB  reply  comments  at  8. 
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 Commissions  planning  factors  are  already  conservative  and  there  is  no  reason  to  account  for  time  variability  by  increasing  the  minimum  signal  strength  standard.  220 
 122.  Evaluation.  Many  of  the  suggestions  made  by  commenters  were  noncontroversial  and  went  unchallenged  in  the  record  of  the  Inquiry.  In  this  regard,  we  note  that  the  NAB  and  the  Network 
 Affiliates  pointed  out  that  the  measurement  rules  are  analog  specific  with  respect  to  the  signal  strength  standard  and  need  to  be  modified.  We  agree  and  as  supported  by  the  record  of  the  Inquiry,  believe  that 
 the  digital  television  measurement  rules  should  specify  the  noise-  limited  field  strength  values  as  the  minimum  signal  level  that  constitutes  service  to  a  household.  We  also  agree  with  the  NAB  and  the 
 Network  Affiliates  that  use  of  the  average  power  in  the  DTV  channel,  rather  than  the  level  of  the  pilot  signal,  would  provide  a  better  measure  of  DTV  signal  strength  for  the  reasons  they  indicate.  Therefore, 
 we  plan  to  initiate  a  rule  making  proceeding  in  the  near  future  to  revise  the  measurement  procedure  to  use  average  power  integrated  over  the  entire  6  megahertz  bandwidth  as  the  basis  for  measuring  the  digital 
 television  signal.  221  As  for  the  question  in  the  Inquiry  regarding  whether  the  i.  f.  of  the  measuring  equipment  needs  to  be  specified,  we  believe  that  it  is  not  necessary  to  specify  an  i.  f.  other  than  that  it 
 cannot  be  greater  than  6  megahertz.  Any  of  the  methods  suggested  above  will  work  and  the  i.  f.  is  essentially  irrelevant  so  long  as  it  is  not  larger  than  6  megahertz  and  the  equipment  is  capable  of 
 integrating  the  power  over  the  selected  i.  f.  bandwidth. 
 123.  We  make  no  make  no  specific  recommendation  on  whether  the  measurement  procedure  should  include  provisions  requiring  the  use  of  a  directional  antenna.  However,  we  believe  there  may  be 


 merit  to  this  suggestion  by  the  NAB  and  the  Network  Affiliates.  We  believe  that  the  proper  place  to  address  this  is  through  a  rule  making  proceeding  conducted  by  the  Commission.  We  point  out,  however, 
 that  should  it  be  determined  through  rule  making  that  a  calibrated  directional  antenna  is  to  be  used,  the  requirements  of  the  antenna  (e.  g.,  gain,  half-  power  beamwidth,  etc.)  must  be  standardized  so  that  the 
 measurement  test  is  not  arbitrarily  subject  to  the  particular  antenna  selected  by  the  tester. 
 124.  Further,  we  agree  with  NAB  and  the  Network  Affiliates  that  digital  television  measurements  should  be  made  at  6.1  meters  (20  feet)  for  one-  story  structures  and  9.1  meters  (30  feet)  for 


 two-  story  or  taller  structures;  the  same  as  analog  television.  This  height  standard  is  central  to  the  definition  of  the  planning  model  for  DTV  service  areas.  We  therefore  recommend  that  the  procedures  for 
 measuring  digital  signals  not  be  changed  from  the  analog  standard  with  respect  to  measurement  height. 
 125.  The  SHVERA  specifically  asks  the  Commission  to  consider  whether  to  account  for  the  fact  that  some  households  use  indoor  antennas.  As  discussed  above  in  the  section  on  signal  strength 


 standards,  the  channel  allotment  plan  for  digital  television  developed  by  the  Commission  which  defines  the  DTV  service  areas  is  premised  on  the  planning  factors;  one  of  which  is  that  an  outdoor  antenna  is 
 used.  Households  may  certainly  employ  indoor  antennas,  but  for  standardized  testing  and  planning  an  objective  procedure  must  be  used.  To  do  otherwise  would  introduce  a  level  of  subjectiveness  such  that 
 the  entire  testing  process  could  be  rendered  meaningless.  To  begin  with,  there  is  the  question  of  where  within  a  household  would  the  testing  take  place?  If  the  antenna  is  in  an  attic,  it  may  not  be  easily 
 accessible  for  conducting  the  test  at  its  location.  Then,  what  if  modifications  are  made  to  the  house,  such  as  new  siding  or  a  new  roof.  Would  that  subject  the  household  to  additional  testing?  And  what  if  there 
 are  several  televisions  in  the  household  using  different  antennas?  In  that  situation,  it  is  possible  to 
 220  Id.  at  9. 
 221  47  U.  S.  C.    339(  a)(  2)(  D)(  vii)  specifies  the  dates  on  which  the  measurement  of  stations  signals  may  begin  for 
 the  purpose  of  determining  if  a  household  is  unserved.  The  earliest  measurement  date  is  April  30,  2006  for  stations  in  top  100  markets  that  have  chosen  a  tentative  digital  channel  that  is  the  same  as  its  current  digital 


 channel  or  have  lost  interference  protection  and  not  been  granted  a  testing  waiver. 
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 conceive  a  scenario  where  one  television  could  be  eligible  for  receiving  a  distant  signal  and  another  could  be  ineligible.  Further,  there  is  the  issue  of  what  antenna  to  use  for  testing.  EchoStar  suggests  using  a 
 typical  antenna,  but  does  not  define  a  typical  antenna.  An  essential  part  of  the  test  system  cannot  be  left  to  choice.  A  good  test  must  be  repeatable.  There  are  too  many  elements  of  variation  in  an  indoor 
 measurement  that  would  render  such  a  test  essentially  meaningless. 
 126.  In  addition,  the  Commission  is  on  record  that  it  expects  households  to  make  similar  efforts  to  receive  digital  television  as  they  made  for  analog.  There  is  good  reason  for  this  position.  If  it 


 was  expected  that  households  could  do  less,  then  it  could  have  the  effect  of  drastically  shrinking  the  service  areas  of  television  stations.  Or,  as  discussed  above,  to  keep  the  same  service  area,  stations  would 
 need  to  significantly  increase  their  power,  which  could  lead  to  interference  situations.  Neither  of  these  outcomes  is  desirable.  Additionally,  many  stations  already  have  fully  operational  digital  television 
 facilities  that  have  been  built  based  on  the  rules  and  policies  in  place.  It  is  our  opinion  that  forcing  these  stations  to  change  now  would  have  an  unknown  effect  on  the  number  of  households  considered  unserved 
 and  could  have  the  effect  of  stifling  the  transition  to  digital  television.  For  the  reasons  articulated  above,  we  recommend  that  the  measurement  procedures  for  determining  whether  a  household  is  unserved  not 
 include  provisions  for  indoor  testing. 
 127.  Concerning  antenna  pointing,  we  continue  to  believe  that  for  testing  purposes  of  determining  if  a  household  is  unserved  under  SHVERA,  the  procedures  should  remain  consistent  with 


 those  in  use  today.  As  with  the  suggestion  above  regarding  the  use  of  indoor  antennas,  we  believe  that  it  would  be  arbitrary  to  allow  for  any  practice  other  than  pointing  the  antenna  in  the  direction  of  maximum 
 signal  strength.  To  allow  other  antenna  orientation  would  not  satisfy  good  engineering  practice  as  the  outcome  would  be  subject  to  the  individual  tester  rather  than  being  objective.  Further,  as  discussed 
 above,  rotors  are  readily  available  at  reasonable  cost  (approximately  $55-$  100).  222  Thus,  there  is  no  undue  burden  on  households  to  use  a  rotor.  To  move  away  from  current  practice,  especially  in  a  manner 
 that  is  subjective,  for  the  purpose  of  determining  if  a  household  is  unserved  under  SHVERA  would  have  the  effect  of  treating  similarly  situated  households  differently  depending  on  the  particular  person 
 conducting  the  measurement.  Thus,  we  recommend  that  the  measurement  procedure  not  be  modified  with  respect  to  the  requirement  to  orient  the  test  antenna  in  the  direction  of  maximum  signal  strength. 


 128.  We  do  not  recommend  that  the  digital  television  measurement  procedures  for  determining  if  a  household  is  unserved  under  SHVERA  include  adjustments  for  multipath  or  time 
 variability  as  suggested  by  EchoStar.  As  the  NAB  states,  our  planning  factors  are  already  conservative  and  overestimate  available  signal  strength.  Thus,  any  variation  in  the  signal  values  due  to  multipath, 
 white  noise  enhancement,  or  time  variability  are  already  more  than  compensated  for.  In  addition,  if  a  time  variability  factor  is  added,  a  long  term  study  possibly  over  several  years  would  need  to  be  conducted 
 for  it  to  be  properly  characterized.  By  the  time  such  a  study  could  be  completed,  it  is  likely  that  the  transition  to  digital  television  would  be  near  completion.  Furthermore,  many  digital  television  stations 
 have  been  operational  for  some  time  now  and  there  is  no  evidence  that  the  current  minimum  signal  strength  values  have  been  inadequate  over  time. 


 129.  Finally,  we  note  that  commenters  did  not  address  co-  channel  or  adjacent  channel  interference  or  clutter  with  respect  to  measurement.  However,  on  this  point,  we  note  that  the 
 Commissions  channel  allotment  procedures  were  designed  to  minimize  the  possibilities  of  this  type  of  interference.  In  addition,  television  manufacturers  are  aware  of  the  planning  factors  and  the 
 Commissions  rules  regarding  interference  levels  and  account  for  interference  in  their  receiver  designs  by  adjusting  the  receiver  selectivity  and  adjacent  channel  rejection  characteristics  of  the  receiver.  We  also 


 222  Network  Affiliates  comments,  exhibit  3  (rotors). 
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 V.  PREDICTIVE  MODELING 
 132.  Currently,  households  have  two  methods  of  determining  if  they  are  unserved  by  a  local  analog  television  signal:  predictive  modeling  and  testing.  Predictive  modeling  is  a  simple,  cost-  effective 
 method  for  determining  if  a  signal  at  a  given  location  meets  certain  criteria  for  availability,  such  as  its  strength  over  a  percentage  of  time.  The  Commission  has  established  a  predictive  model  that  evaluates  the 
 coverage  and  interference  of  a  particular  digital  TV  station.  This  model,  described  in  OET  Bulletin  69,  uses  the  Longley-  Rice  radio  propagation  model  to  make  predictions  of  radio  field  strength  at  specific 
 geographic  points  based  on  the  elevation  profile  of  terrain  between  the  transmitter  and  each  specific  reception  point.  223  The  Commission,  in  accordance  with  SHVIA,  has  also  implemented  the  use  of  a 
 modified  Longley-  Rice  model  known  as  the  Individual  Location  Longley-  Rice  (ILLR)  model,  for  identifying  unserved  households  attempting  to  receive  analog  broadcast  signals.  224  We  implemented  an 
 improved  version  of  the  ILLR  model  in  order  to  make  the  predictive  model  more  accurate  by  taking  terrain  features  (such  as  hills),  buildings,  and  land  cover  (such  as  forests)  into  account.  225 


 133.  The  ILLR  model  has  proven  over  time  to  be  an  accurate  and  reliable  predictor  of  signal  strength  and  has  been  well  accepted  by  both  the  broadcast  and  DBS  industries.  In  the  current  satellite 
 distant  signal  eligibility  scheme  for  analog  television  signals,  predictive  modeling  is  used  first  to  determine  a  households  status  as  served  or  unserved  by  a  local  television  signal.  Based  on  the  models 
 results  a  household  may  request  an  actual  field  measurement  if  it  believes  the  predictive  modeling  is  not  an  accurate  predictor  of  actual  conditions.  Under  the  SHVERA,  Congress  provided  that  eligibility 


 223  See  OET  Bulletin  69,  "Longley-  Rice  Methodology  for  Evaluating  TV  Coverage  and  Interference".  A  computer 
 is  needed  to  make  these  predictions  because  of  the  large  number  of  reception  points  that  must  be  individually  examined.  Computer  code  for  the  Longley-  Rice  point-  to-  point  radio  propagation  model  is  published  in  an 


 appendix  of  NTIA  Report  82-  100,  A  Guide  to  the  Use  of  the  ITS  Irregular  Terrain  Model  in  the  Area  Prediction  Mode,  authors  G.  A.  Hufford,  A.  G.  Longley  and  W.  A.  Kissick,  U.  S.  Department  of  Commerce,  April  1982.  Some 
 modifications  to  the  code  were  described  by  G.  A.  Hufford  in  a  memorandum  to  users  of  the  model  dated  January  30,  1985.  With  these  modifications,  the  code  is  referred  to  as  Version  1.2.2  of  the  Longley-  Rice  model.  This 
 version  is  used  by  the  FCC  for  its  evaluations. 
 224  See  OET  Bulletin  72,  "The  ILLR  Computer  Program".  OET  Bulletin  72  details  the  computer  program  that  the 
 Commission  was  instructed  by  Congress  to  established  under  SHVIA  in  Section  339(  c)(  3)  of  the  Communication  Act.  It  provides  that  "[  i]  n  prescribing  such  model,  the  Commission  shall  rely  on  the  Individual  Location  Longley-Rice 


 (ILLR)  model  set  forth  by  the  Federal  Communications  Commission  in  Docket  No.  98-  201  and  ensure  that  such  model  takes  into  account  terrain,  building  structures,  and  other  land  cover  variations."  See  also  See  Satellite 
 Delivery  of  Network  Signals  to  Unserved  Households  for  Purposes  of  the  Satellite  Home  Viewer  Act;  Part  73  Definition  and  Measurement  of  Signals  of  Grade  B  Intensity,  Report  and  Order,  CS  Docket  No.,  98-  201,  14  FCC 
 Rcd  2654  (1999).  A  computer  is  needed  to  make  these  predictions  because  of  the  large  number  of  reception  points  that  must  be  individually  examined.  Computer  code  for  the  ILLR  point-  to-  point  radio  propagation  model  is 
 published  in  an  appendix  of  NTIA  Report  82-  100,  A  Guide  to  the  Use  of  the  ITS  Irregular  Terrain  Model  in  the  Area  Prediction  Mode,  authors  G.  A.  Hufford,  A.  G.  Longley  and  W.  A.  Kissick,  U.  S.  Department  of  Commerce, 
 April  1982.  Some  modifications  to  the  code  were  described  by  G.  A.  Hufford  in  a  memorandum  to  users  of  the  model  dated  January  30,  1985.  With  these  modifications,  the  code  is  referred  to  as  Version  1.2.2  of  the  Longley-Rice 
 model. 
 225  Id.  The  Inquiry  indicated  several  features  of  the  improved  ILLR  model  that  make  it  unique.  These  include:  the 
 time  variability  factor  is  50%  and  the  confidence  variability  factor  is  50%;  the  model  is  run  in  individual  mode;  terrain  elevation  is  considered  every  1/  10  of  a  kilometer;  the  receiving  antenna  height  is  assumed  to  be  20  feet  above 


 ground  for  one-  story  buildings  and  30  feet  above  ground  for  buildings  taller  than  one-  story;  land  use  and  land  cover  (e.  g.,  vegetation  and  buildings)  is  accounted  for;  where  error  codes  appear,  they  shall  be  ignored  and  the  predicted 
 value  accepted  or  the  result  shall  be  tested  with  an  on-  site  measurement;  and  locations  both  within  and  beyond  a  station's  Grade  B  contour  shall  be  examined. 
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 determinations  be  made  only  on  the  basis  of  field  testing  and  did  not  include  any  provisions  for  use  of  predictive  modeling.  Recognizing  the  benefits  of  predictive  modeling,  however,  Congress,  in  Section 
 339(  c)(  1)(  B)(  iv)  of  the  amended  Communications  Act,  asked  the  Commission  to  consider  whether  to  develop  a  predictive  methodology  for  determining  whether  a  household  is  unserved  by  an  adequate  digital 
 signal  under  section  119(  d)(  10)  of  title  17,  United  States  Code.  226  On  a  related  issue,  in  Section  339(  c)(  1)(  B)(  vi)  Congress  also  requested  that  the  Commission  consider  whether  to  account  for  factors 
 such  as  building  loss,  external  interference  sources,  or  undesired  signals  from  both  digital  television  and  analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets,  foliage,  and  man-made 
 clutter.  227 
 134.  To  examine  these  issues,  the  Commission,  in  the  Inquiry,  requested  comment  on  whether  the  improved  ILLR  model,  with  appropriate  modifications,  would  accurately  predict  digital  signal 


 coverage  at  a  specific  location,  or  whether  there  is  some  other  predictive  model  that  would  be  more  appropriate  for  this  purpose.  The  Commission  asked  that  commenters  who  propose  either  specific 
 modifications  to  the  improved  ILLR  model  or  alternative  models  provide  detailed  analysis  as  to  how  their  proposed  modifications  will  improve  the  ILLR  models  prediction  characteristics  and/  or  an  explanation  of 
 how  the  changes  or  alternatives  would  more  accurately  model  the  available  signal  level  when  accounting  for  terrain  and  possible  signal  interference. 


 135.  Inquiry  Record:  The  parties  commenting  in  our  Inquiry  were  supportive  of  the  Commission  developing  a  predictive  model.  For  example,  DirecTV  states  that  the  most  important  lesson 
 from  the  last  decade  of  distant  network  signal  qualification  with  regard  to  analog  television  is  that  predictive  modeling  is  better  than  on-  site  testing.  EchoStar  submits  that  it  appears  that  the  predictive 
 methodology  currently  used  in  the  SHVA  context,  i.  e.,  the  ILLR  model,  has  considerable  applicability  to  the  DTV  world,  although  there  remain  improvements  that  might  be  made  to  accommodate  reliable  DTV 
 reception.  In  supporting  the  ILLR  model,  the  Network  Affiliates  explain  that  on-  site  testing  is  not  the  norm  today  228  and  that  on-  site  testing  frustrates  and  inconveniences  subscribers,  costs  more  money  than  it 
 is  worth,  and  should  only  be  used  as  a  last  resort.  229  DirecTV  describes  the  current  process  as  one  in 


 226  See  47  U.  S.  C.    339(  c)(  1)(  B)(  iv).  17  U.  S.  C.    119(  d)(  10)  provides  the  following  definition  of  unserved 
 household: 


 (10)  Unserved  household.  The  term  unserved  household,  with  respect  to  a  particular  television  network,  means  a  household  that 


 (A)  cannot  receive,  through  the  use  of  a  conventional,  stationary,  outdoor  rooftop  receiving  antenna,  an  over-  the-  air  signal  of  a  primary  network  station 
 affiliated  with  that  network  of  Grade  B  intensity  as  defined  by  the  Federal  Communications  Commission  under  section  73.  683(  a)  of  title  47  of  the  Code  of 
 Federal  Regulations,  as  in  effect  on  January  1,  1999;  (B)  is  subject  to  a  waiver  granted  under  regulations  established  under  section 
 339(  c)(  2)  of  the  Communications  Act  of  1934;  (C)  is  a  subscriber  to  whom  subsection  (e)  applies; 
 (D)  is  a  subscriber  to  whom  subsection  (a)(  11)  applies;  or  (E)  is  a  subscriber  to  whom  the  exemption  under  subsection  (a)(  2)(  B)(  iii) 
 applies. 
 227  See  47  U.  S.  C.    339(  c)(  1)(  B)(  vi). 


 228  DirecTv  states  that  in  last  five  years  only  3,200  customers  (0.  3%)  of  those  requesting  distant  network  signals 
 asked  for  an  on-  site  test,  and  only  about  1,400  of  those  actually  received  a  test.  DirecTv  comments  at  2. 
 229  DirecTv  comments  at  2. 
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 which  subscribers  must  wait  at  least  30  days  after  receiving  the  results  of  predictive  modeling  while  broadcasters  decide  whether  to  grant  a  waiver  for  them  to  receive  distant  network  signals.  It  states  that  if 
 such  a  waiver  is  denied,  then  the  subscriber  must  wait  until  an  independent,  qualified  tester  can  be  identified  in  their  area,  wait  for  the  tester  to  arrange  an  appointment  and  wait  for  the  test  to  take  place 
 (and  often  tests  are  delayed  due  to  weather  or  scheduling  issues).  230  It  further  states  that  because  the  actual  test  is  of  a  signal  level  rather  than  someone  looking  at  their  television  picture,  customers  get 
 frustrated  with  the  testing  process.  231  Finally,  it  provides  that  testing  is  a  losing  proposition  as  the  average  cost  of  a  test  is  approximately  $150  (with  some  as  high  as  $450)  and  that  it  takes  at  least  five  years  to 
 recoup  that  cost  from  subscriber  revenue.  232 
 136.  Those  that  commented  on  this  issue  all  endorse  use  of  the  improved  ILLR  model  that  the  Commission  has  already  been  using.  CEA  states  that  the  ILLR  model  is  a  very  good  tool  with  years  of 


 engineering  development  and  that  it  is  not  aware  of  any  industry  discussion  regarding  a  better  model  for  this  purpose.  233  The  Network  Affiliates  recommend  use  of  the  ILLR  model.  They  state  that  analog  TV 
 coverage  is  predicated  upon  this  model  and  the  broadcast  and  satellite  industries  have  five  years  of  experience  with  its  use.  234  However,  the  NAB  and  the  Network  Affiliates  submit  that  a  DTV  ILLR  model 
 should  only  be  used  after  the  transition  to  digital  television  is  complete.  They  believe  that  otherwise  the  process  would  be  too  complicated  and  confusing.  235  In  this  regard,  the  NAB  explains  that  in  the  short 
 term  (prior  to  the  end  of  the  digital  transition)  problems  could  arise  due  to  variations  in  dates  that  different  stations  will  actually  begin  broadcasting  digital  signals.  236  It  states  that  few  translator  stations  have 
 channel  assignments,  much  less  fully  functioning  facilities  and  many  full  power  stations  wont  be  subject  to  testing  until  July  2007  or  later.  237  The  NAB  further  states  that  Congress  postponed  the  date  on  which 
 many  broadcast  stations  would  begin  to  be  subject  to  testing  because  Congress  recognized  that  it  would  be  unfair  to  penalize  a  station  for  not  delivering  a  digital  signal  when  it  cannot  be  reasonably  expected  to 
 do  so.  238  It  contends  that  Congress  created  a  complex  and  somewhat  unpredictable  schedule  for  when 
 230  Id.  comments  at  2-  3. 


 231  Id.  comments  at  3-  4. 
 232  Id.  comments  at  4-  l 
 233  CEA  comments  at  4. 
 234  Network  Affiliates  comments  at  44-  45. 
 235  Id.  comments  at  43-  44. 
 236  NAB  comments  at  vi-  vii  and  31-  33. 
 237  Id.  comments  at  31.  The  testing  referred  to  here  is  the  measurement  at  an  individual  subscribers  location  of  a 
 digital  television  signal  level  for  the  purpose  of  determining  if  the  subscriber  at  that  location  is  considered  unserved  and  therefore  eligible  to  receive  a  distant  network  signal. 


 238  Id.  comments  at  34-  35.  47  U.  S.  C.    339(  a)(  2)(  D)(  vii)  provides  trigger  dates  for  testing.  NAB  characterizes  the 
 schedule  set  up  by  Congress  as  testing  to  begin  on  April  30,  2006,  for  stations  in  top  100  markets  that  have  chosen  a  tentative  digital  channel  that  is  the  same  as  its  current  digital  channel  and  have  not  been  granted  a  testing  waiver  and 


 for  stations  in  top  100  markets  that  have  been  found  to  have  lost  interference  protection.  Testing  begins  on  July  15,  2007  for  stations  in  top  100  markets  that  have  chosen  a  tentative  digital  channel  different  from  its  current  digital 
 channel  and  have  not  been  granted  a  testing  waiver  and  for  stations  below  the  top  100  markets  that  have  not  been  granted  a  testing  waiver.  Finally,  there  are  unknown  future  dates  for  translator  stations    one  year  after  the  date  on 
 which  commission  completes  all  actions  necessary  for  allocation  and  assignment  of  digital  television  licenses  to  translator  stations;  and  for  full  power  stations  with  testing  waivers    continue  to  be  exempt  from  testing  as  long  as 
 extensions  of  waivers  are  approved. 
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 stations  would  be  subject  to  testing  in  order  to  protect  stations  from  a  draconian  loss  of  viewers  due  to  circumstances  beyond  their  control.  On  this  point,  the  NAB  argues  that  since  Congress  barred  site  testing 
 of  certain  stations  digital  signals,  it  would  be  equally  improper  to  subject  those  stations  to  predictions  of  the  signal  strength  of  those  same  signals.  239  The  Network  Affiliates  offer  similar  comments.  240  The  NAB 
 further  comments  that  it  believes  that  what  Congress  intended  here  is  that  if  a  station  is  not  yet  eligible  to  have  its  digital  signal  evaluated,  then  the  analog  signal  should  be  evaluated  instead.  This,  the  NAB  and 
 the  Network  Affiliates  aver,  would  be  the  logical  way  to  give  stations  credit  for  coverage  when  they  have  been  excluded  from  testing.  241 


 137.  The  NAB  continues  that  the  ILLR  model  should  be  used  in  the  long  term  (after  the  digital  transition)  because  it  does  exceptionally  well  at  predicting  whether  or  not  particular  locations  will  receive 
 a  signal  above  the  DTV  minimums.  It  states  that  the  model  provides  correct  predictions  95%  of  the  time  and  that  when  errors  do  occur  they  are  evenly  divided  between  over  and  under  predictions.  242  MSW 
 draws  a  similar  conclusion  for  use  of  the  ILLR  model  with  respect  to  DTV.  It  studied  real  world  empirical  data  from  thousands  of  measurements  in  12  different  U.  S.  cities  and  submits  that  the  data  shows 
 that  the  Longley-  Rice  model  correctly  predicted  94.4%  of  the  time  when  the  signal  would  be  above  the  DTV  minimum.  243 


 138.  EchoStar  submits  that  changes  are  needed  in  the  ILLR  predictive  model  to  make  it  suitable  for  use  in  predicting  the  availability  of  DTV  signals.  It  states  that  the  model  should  be  modified 
 to  include  an  improved  time  variability  factor  and  to  incorporate  more  realistic  values  for  system  noise,  building  penetration,  and  land  cover  and  clutter.  244  EchoStar  submits  that  the  analog  ILLR  model  is  based 
 on  a  time  variability  factor  of  50%,  which  means  that  the  model  assumes  that  a  household  is  unable  to  receive  an  analog  signal  at  or  above  the  minimum  level  about  half  of  the  time.  245  It  infers  that  for  digital 
 television  this  similarly  means  that  there  will  be  an  inability  to  receive  a  digital  picture  about  half  the  time.  EchoStar  avers  that  even  a  time  variability  factor  of  90%  means  a  subscriber  will  not  have 
 reception  for  up  to  5  weeks  a  year.  As  a  remedy,  it  suggests  that  the  model  be  modified  to  incorporate  an  increase  in  temporal  reliability  to  99%  or  more  until  there  is  greater  experience  with  digital  television.  246 
 H&  E  also  argues  that  90%  time  reliability  seems  not  to  be  in  the  consumers  best  interest.  247  The  NAB  and  the  Network  Affiliates  counter  EchoStar  by  stating  that  changing  to  a  99%  time  variability  factor 
 amounts  to  changing  the  rules  in  the  middle  of  the  game.  248  MSW  avers  that  EchoStar  overestimates  the 
 239  Id.  at  36. 


 240  Network  Affiliates  comments  at  43-  44. 
 241  NAB  comments  at  37. 
 242  Id.  NAB  comments  at  vi. 
 243  NAB  comments  at  MSW  engineering  study  at  28. 
 244  EchoStar  comments  at  9. 
 245  As  discussed  below  (and  above  in  the  section  on  signal  strength),  the  signal  strength  standards  in  the  rules  are 
 in  fact  based  on  an  F(  50,  90)  level  of  signal  availability,  which  implies  that  a  signal  would  be  available  at  least  90%  of  the  time,  not  50%  as  EchoStar  incorrectly  states. 


 246  Id. 
 247  EchoStar  comments  at  H&  E  engineering  study  at  7. 
 248  NAB  reply  comments  at  8;  Network  Affiliates  reply  comments  at  8. 
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 impact  of  the  time  variability  factor.  It  explains  that  any  loss  of  service  does  not  occur  over  the  entire  service  area,  but  only  at  outer  edges  of  a  television  stations  service  area  and  even  there  any  outage  that 
 occur  are  not  consecutive,  nor  is  the  time  duration  of  a  particular  outage  known.  MSW  states  that  many  instances  of  service  loss  will  occur  during  times  when  no  one  is  watching  TV  or  may  be  so  short  as  to 
 only  cause  a  momentary  disruption.  MSW  offers  that  for  those  households  at  the  edge  of  the  service  area,  reception  can  be  improved  with  a  mast-  mounted  low  noise  amplifier  (LNA).  249 


 139.  With  respect  to  system  noise,  EchoStar  states  that  the  planning  factors  underlying  the  Commissions  DTV  field  strength  standards  assume  that  the  impedance  is  matched  between  the  receiver 
 and  the  antenna.  250  It  claims  that  this  is  rarely  the  case  in  practice  and  that  the  predictive  model  should  take  this  into  account  and  use  a  noise  figure  increased  by  3  dB  to  correct  for  this  inaccuracy  in  the 
 planning  factors.  251  EchoStar  obtains  this  3  dB  figure  by  observing  that  many  DTV  antennas  have  voltage  standing  wave  ratio  252  (VSWR)  values  that  exceed  3:  1  over  much  of  their  design  bandwidth  and  that 
 exceed  2:  1  over  essentially  all  of  their  design  bandwidth.  253  On  this  point,  MSW  argues  that  impedance  mismatch  loss  between  a  TV  antenna  and  receiver  as  well  as  a  higher  digital  television  receiver  noise 
 figure  can  be  mitigated  by  a  mast-  mounted  LNA.  In  cases  where  such  losses  might  be  a  problem,  MSW  states  that  an  LNA  resolves  the  matter  by  isolating  the  antenna  impedance  from  that  of  the  downlead 
 coaxial  cable  and  the  DTV  tuner  input  impedance.  254 
 140.  EchoStar  also  argues  that  the  DTV  predictive  model  should  account  for  building  penetration.  It  contends  that  the  H&  E  study  shows  building  loss  at  VHF  can  be  as  high  as  30  dB  for  high 


 clutter  areas.  It  adds  that  further  study  may  yield  a  more  complete  set  of  figures  on  building  penetration  loss  for  incorporation  into  the  model,  especially  for  apartment  dwellers  with  indoor  antennas.  255  MSW 
 argues  that  as  far  as  the  model  is  concerned  building  penetration  is  irrelevant  given  that  TV  service  should  be  established  on  the  basis  of  an  outdoor  model  and  that  therefore  indoor  measurements  should  not  be 
 performed.  256 
 141.  Finally,  on  the  topic  of  land  use  and  land  clutter,  EchoStar  notes  that  the  Commission  has  recognized  that  incorporation  of  such  factors  into  the  predictive  model  would  increase  the  models 


 accuracy.  However,  it  observes  that  the  Commission  has  set  almost  all  the  clutter-  loss  values  for  VHF  channels  to  zero.  It  argues  that  this  is  a  problem  for  analog  television,  but  an  even  larger  problem  for 


 249  MSW  reply  comments  at  10;  Network  Affiliates  reply  comments  at  7. 
 250  Impedance  is  the  total  passive  opposition  offered  to  the  flow  of  electric  current,  see  Federal  Standard  1037C, 
 Telecommunications:  Glossary  of  Telecommunications  Terms,  1996. 
 251  EchoStar  comments  at  10. 


 252  Voltage  standing  wave  ratio  is  the  ratio  of  the  maximum  to  the  minimum  voltage  in  a  standing  wave  pattern  in 
 a  transmission  line.  VSWR  is  a  measure  of  impedance  mismatch  between  a  transmission  line  and  its  load;  the  higher  the  VSWR,  the  greater  the  mismatch,  where  a  VSWR  of  1  corresponds  to  a  perfect  impedance  match.  See 


 Federal  Standard  1037C,  Telecommunications:  Glossary  of  Telecommunications  Terms,  1996. 
 253  EchoStar  comments  at  H&  E  engineering  statement  at  11-  12. 


 254  MSW  reply  comments  at  14. 
 255  EchoStar  comments  at  10. 
 256  MSW  reply  comments  at  14. 
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 digital  because  if  the  signal  level  falls  below  the  minimum  needed,  then  the  entire  picture  is  lost.  257  NAB  notes  that  the  ILLR  model  is  partially  based  on  actual  field  measurements  and  thus  already  takes  clutter 
 into  account  to  a  significant  degree  because  clutter  affects  real  world  field  measurements.  It  also  states  that  the  ILLR  model  is  already  in  balance  at  low-  VHF  and  so  no  additional  factors  to  adjust  for  clutter 
 loss  are  needed.  258 
 142.  Evaluation.  When  it  enacted  the  SHVIA,  Congress  explicitly  provided  for  the  Commission  to  prescribe  a  predictive  model  to  evaluate  if  a  household  is  unserved  by  an  analog  television 


 signal.  That  model    the  modified  individual  location  Longley-  Rice  propagation  model  -  has  served  the  industry  well  as  it  has  proven  to  be  highly  accurate  over  time.  Through  the  use  of  this  model,  both 
 consumers  and  terrestrial  and  satellite  television  operators  have  saved  considerable  time,  money,  and  frustration  that  would  come  with  having  to  conduct  an  actual  measurement  test  every  time  a  satellite 
 customer  believes  that  he/  she  is  unable  to  receive  an  adequate  signal  off-  the-  air  from  a  local  television  network  affiliated  station.  The  same  situation  is  likely  to  exist  with  regard  to  digital  television  signals. 
 Therefore,  we  recommend  that  Congress  provide  for  the  Commission  to  explore  a  similar  model  for  digital  television  through  a  rule  making  proceeding. 


 143.  Those  commenters  that  provided  input  on  this  issue  were  all  in  agreement  that  a  predictive  model  should  be  available  for  determining  if  a  household  is  unserved  by  a  digital  television 
 signal  and  that  the  model  be  the  ILLR.  We  agree  with  those  comments.  The  Longley-  Rice  propagation  model  has  been  used  for  considerable  time  and  it  has  proven  to  be  highly  accurate  at  predicting  the  field 
 strengths  of  television  stations  at  a  location.  This  is  illustrated  by  the  data  presented  by  the  commenters  showing  an  accuracy  rate  of  almost  95%.  259  Additionally,  because  the  standard  Longley-  Rice  point-  to-point 
 coverage  model  was  used  to  develop  the  digital  television  allotment  plan,  the  industry  already  has  considerable  practice  using  this  model  for  digital  television  in  addition  to  the  experience  gained  for 
 analog  television  over  the  last  few  years.  And  since  there  do  not  seem  to  be  any  candidate  models  that  would  offer  superior  performance  to  the  improved  ILLR  propagation  model,  a  change  at  this  point  in  time 
 would  entail  substantial  development  and  testing  which  would  likely  not  be  completed  until  after  the  transition  to  digital  television  is  complete  and  a  time  when  the  satellite  television  providers  offer  local-into- 
 local  signals  for  most,  if  not  all,  TV  designated  market  areas  (DMAs).  It  is  anticipated  that  at  that  point  the  requirements  of  SHVERA  with  respect  to  distant  signal  retransmission  will  be  moot  in  most 
 cases. 
 144.  We  note  that  while  endorsing  use  of  the  ILLR,  NAB  and  the  Network  Affiliates  advocate  its  use  only  after  the  digital  transition  is  complete,  arguing  that  its  use  prior  to  this  time  would  be 


 confusing  and  serve  to  penalize  stations  that  transition  to  broadcasting  digital  signals  later  rather  than  earlier  but  still  in  accordance  with  the  prescribed  timetable.  260  They  argue  that  local  stations  that  build 
 out  their  digital  facilities  at  a  later  time  would  lose  their  local  viewers  to  a  distant  network  signal  even  though  they  are  fully  compliant  with  the  law  and  the  Commissions  rules.  We  agree  with  NAB  and  the 
 Network  Affiliates  that  the  timing  governing  the  use  of  a  predictive  model  should  be  consistent  with  the  SHVERA  provisions  that  permit  subscribers  to  receive  distant  digital  signals  under  specified 
 circumstances.  These  provisions  take  account  of  various  factors  that  could  legitimately  prevent  a  station 


 257  EchoStar  comments  at  10-  11. 
 258  Network  Affiliates  comments  at  44-  47. 
 259  NAB  comments  at  MSW  engineering  study  at  28. 
 260  [add  a  cite  to  the  NAB  and  Network  Affiliates  Comments] 
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 from  serving  its  potential  digital  service  area  at  this  time.  261  The  provision  of  the  statute  cited  by  NAB  and  the  Network  Affiliates  applies  to  subscribers  who  are  eligible  for  testing  (i.  e.,  subscribers  who  live 
 within  the  area  predicted  to  be  served  by  the  analog  predictive  model  of  a  local  network  station  and  are  seeking  a  distant  digital  signal  for  a  station  affiliated  with  the  same  network  as  the  local  network 
 station).  262  This  provision  further  provides  that  stations  that  may  be  subject  to  a  digital  signal  test  may  request  a  waiver  from  the  Commission  to  prohibit  such  testing  if  the  station  proves  that  it  satisfies  the 
 statutory  criteria  related  to  unremediable  limitations  on  the  stations  digital  signal  coverage.  263  Thus,  if  Congress  amends  the  statutory  provisions  to  recognize  a  predictive  model  with  respect  to  digital  signals 
 and  provides  discretion  for  the  Commission  to  develop  such  a  model,  the  appropriate  timing  for  use  of  the  model  should  also  be  considered  by  Congress  in  conjunction  with  such  legislative  changes.  Congress 
 could,  for  example,  provide  that  use  of  the  model  would  be  subject  to  the  same  waiver  provisions  that  apply  to  stations  with  respect  to  digital  signal  testing.  264  We  also  note  that  Congress  is  currently 
 considering  legislation  to  mandate  the  date  on  which  the  transition  to  digital  television  would  end,  which,  in  turn,  is  likely  to  influence  the  timing  for  use  of  a  predictive  model. 


 145.  There  were  several  suggestions  made  by  commenters  for  further  changing  the  ILLR  model.  These  include  changing  the  time  variability  factor,  and  incorporating  different  values  for  system 
 noise  figure,  building  penetration,  and  land  cover  and  clutter.  First,  EchoStar  argues  that  the  time  variability  factor  for  DTV  should  be  increased  from  50%  to  99%.  We  first  note  that  the  noise-  limited 
 contour  that  defines  the  digital  television  service  area  is  based  on  planning  factors  which  specify  use  of  the  F(  50,  90)  curves,  not  the  F(  50,  50)  curves  as  implied  by  EchoStar;  that  is  the  digital  signal  level  is  at 
 or  above  the  minimum  level  at  50%  of  the  locations  for  90%  of  the  time,  not  50%  of  the  time  as  suggested  by  EchoStar.  265  We  also  note  that  the  90%  availability  level  defines  the  edge  of  a  stations  service  area 
 and  that  at  locations  inside  this  contour  the  availability  percentage  would  be  greater  than  90%.  Further,  as  stated  by  MSW,  the  time  when  a  signal  is  below  the  specified  minimum  value  is  likely  to  occur  in  small 
 increments,  some  of  which  are  when  viewers  are  not  even  watching  television.  Thus,  only  a  small  minority  of  the  total  number  of  viewers  may  experience  outages  as  high  as  10%  of  the  time.  We  also 
 observe  that  the  90%  availability  level  has  been  used  to  define  analog  TV  service  and  has  historically  served  viewers  well.  For  these  reasons,  we  do  not  recommend  any  changes  to  the  digital  television  time 
 variability  factor  for  the  purposes  of  SHVERA. 
 146.  EchoStar  also  argues  that  the  input  for  the  system  noise  figure  to  the  predictive  model  should  be  increased  by  3  dB  to  account  for  impedance  mismatch  between  the  antenna  and  the  receiver. 


 We  agree  with  EchoStar  that  there  may  be  some  loss  in  the  transmission  line  and  associated  balun  due  to  impedance  mismatch.  However,  we  do  not  believe  that  this  loss  is  significant  or  that  the  predictive  model 
 input  needs  to  be  modified  to  account  for  such  loss.  First,  as  NAB  states  and  we  discuss  above,  our  planning  factors  are  conservative  in  that  the  available  coaxial  cable  generally  have  losses  less  than  those 


 261  See,  e.  g.,  47  U.  S.  C.    339(  a)(  2)(  D)(  viii).  These  provisions  further  recognize  that  household  digital  signal 
 testing  with  respect  to  translators  is  on  a  different  schedule  from  full  power  stations.  47  U.  S.  C.    339(  a)(  2)(  D)(  vii)(  II). 


 262  47  U.  S.  C.    339(  a)(  2)(  D)(  vii)(  I). 
 263  47  U.  S.  C.    339(  a)(  2)(  D)(  viii).  See  also  47  U.  S.  C.    339(  a)(  2)(  D)(  ix)  (providing  special  waiver  provision  for 
 translator  stations). 
 264  47  U.  S.  C.    339(  a)(  2)(  D)(  viii),  (ix). 


 265  See  47  C.  F.  R.    73.  622(  e). 
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 assumed  in  the  planning  factors.  266  Second,  there  are  readily  available  devices  that  consumers  can  use,  including  LNAs,  to  reduce  mismatch  in  the  transmission  line  and  thus  reduce  such  loss.  We  also  believe 
 that  the  other  planning  factors  such  as  antenna  gain  and  receiver  noise  performance  are  generally  conservative  such  that  together  there  is  sufficient  margin  to  compensate  for  any  signal  losses  that  may 
 result  from  impedance  mismatching.  We  therefore  see  no  reason  that  the  system  noise  figure  should  be  increased  for  the  purpose  of  using  a  predictive  model  to  determine  if  a  household  is  unserved. 


 147.  Another  area  where  EchoStar  seeks  changes  in  the  improved  ILLR  predictive  model  is  signal  loss  from  building  penetration.  We  disagree  that  this  model  should  be  augmented  to  account  for 
 signal  loss  from  building  penetration.  As  discussed  above  in  the  section  on  signal  measurement,  the  channel  allotment  plan  for  digital  television  is  based  on  the  assumption  that  an  outdoor  antenna  is  used 
 and  the  expectation  that  households  will  make  similar  efforts  to  receive  digital  television  as  they  made  for  analog.  Thus,  any  predictive  modeling  must  reflect  these  assumptions  consistent  with  the  digital 
 television  planning  factors.  Otherwise,  inaccurate  results  will  ensue  which  could  have  the  effect  of  decreasing  confidence  in  the  model.  In  addition,  there  is  no  accepted  value  for  modeling  the  loss  for 
 building  penetration  as  this  phenomenon  varies  depending  on  the  building  materials,  configuration  of  the  structure,  and  other  related  factors.  For  these  reasons,  and  given  our  recommendation  in  the  section  on 
 measurement  procedure  that  all  measurements  continue  to  be  conducted  outside,  there  is  no  reason  for  a  predictive  model  to  assume  any  building  penetration  loss.  Therefore,  we  do  not  recommend  that  the 
 model  input  reflect  any  such  losses. 
 148.  The  last  area  where  commenters  seek  changes  in  the  predictive  model  is  with  respect  to  land  use  and  land  clutter.  Currently,  the  predictive  model  used  for  analog  television  accounts  for 


 additional  signal  loss  due  to  land  use  and  land  clutter.  In  developing  the  land  use  and  land  clutter  adjustment  values,  the  Commission  determined,  after  careful  consideration  of  the  available  data,  that  the 
 correct  loss  value  for  VHF  channels  is  0  dB  in  all  cases  and  for  UHF  channels  the  loss  values  vary  depending  on  the  type  of  land  cover  over  which  the  television  signal  propagates.  267  EchoStar  argues  that 
 in  addition  to  the  loss  added  for  UHF  channels,  there  should  be  some  loss  associated  with  VHF  channels.  NAB  and  the  Network  Affiliates  argue  otherwise  and  take  the  position  that  the  improved  ILLR  model 
 already  takes  clutter  into  account  to  a  significant  degree  because  the  model  is  partially  based  on  actual  field  measurements  and  clutter  affects  real  world  field  measurements.  Any  predictive  model  that  is 
 prescribed  should  provide  output  that  is  as  accurate  as  possible;  anything  less  would  diminish  its  value  as  a  tool  for  determining  whether  a  household  is  able  to  receive  off-  the-  air  digital  television  signals.  For  the 
 analog  model,  we  believe  that  we  struck  the  correct  balance  for  clutter  loss.  This  has  been  borne  out  by  the  data  on  the  record  of  its  performance,  which  shows  that  using  the  values  adopted  by  the  Commission 
 the  ILLR  model  produces  approximately  an  equal  number  of  over  predictions  as  under  predictions.  268  Thus,  a  range  of  values,  including  zero,  that  correspond  to  different  land  cover  types  are  valid.  For  any 
 digital  model  that  may  be  developed,  we  believe  that  the  values  currently  in  use  for  the  analog  model  will  similarly  yield  accurate  results.  We  believe  that  the  proper  arena  for  discussing  correct  clutter  loss  values 
 is  in  a  rule  making  proceeding.  Therefore,  we  believe  that  a  range  of  clutter  loss  values  ranging  from  zero  upwards  may  all  be  valid  inputs  for  a  version  of  the  ILLR  model  that  is  used  for  predicting  the  availability 
 of  digital  television  signals  and  recommend  that  clutter  loss  values  be  determined  and  then  incorporated  into  the  digital  model  through  a  process  similar  to  that  used  to  determine  the  clutter  loss  values  used  in  the 
 analog  TV  ILLR  model. 


 266  NAB  reply  comments  at  11. 
 267  See  ILLR  First  Report  and  Order  at    14-  15. 
 268  Id. 
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 149.  Summary  of  Predictive  Model  Recommendations.  In  summary  then,  we  recommend  that  Congress  amend  the  copyright  and  Communications  Act  to  recognize  digital  signal  strength  predictions 
 for  the  purpose  of  determining  whether  a  subscriber  is  "unserved."  We  also  recommend  that  Congress  provide  the  Commission  with  authority  to  develop  a  predictive  model  for  the  purpose  of  determining 
 households  that  are  unserved  by  local  digital  signals  for  purposes  of  determining  eligibility  to  receive  retransmitted  distant  network  signals  under  the  SHVERA.  For  such  purpose,  we  recommend  that  the 
 existing  Individual  Location  Longley-  Rice  (ILLR)  predictive  model  be  used.  This  model  has  been  used  to  develop  the  channel  allotment  plan  and  we  do  not  believe  that  any  additional  changes  to  the  model 
 inputs  are  necessary  for  purposes  of  SHVERA. 
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 A-  1 
 APPENDIX  A 
 Section  339(  c)(  1)  of  the  Communications  Act  of  1934,  As  Amended 


 Section  339(  c)(  1)  of  the  Communications  Act  of  1934,  as  amended  by  the  SHVERA,  provides  as  follows: 
 (1)  STUDY  OF  DIGITAL  STRENGTH  TESTING  PRODEDURES- 
 (A)  STUDY  REQUIRED-  Not  later  than  one  year  after  the  date  of  the  enactment  of  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004,  the  Federal 


 Commissions  Commission  shall  complete  an  inquiry  regarding  whether,  for  purposes  of  identifying  if  a  household  is  unserved  by  an  adequate  digital  signal  under  section  119(  d)(  10) 
 of  title  17,  United  States  Code,  the  digital  signal  strength  standard  in  section  73.622(  e)(  1)  of  title  47,  Code  of  Federal  Regulations,  such  statutes  or  regulations  should  be  revised  to  take 
 into  account  the  types  of  antennas  that  are  available  to  consumers. 
 (B)  STUDY  CONSIDERATIONS-  In  conducting  the  study  under  this  paragraph,  the  Commission  shall  consider  whether-- 


 (i)  to  account  for  the  fact  that  an  antenna  can  be  mounted  on  a  roof  or  placed  in  a  home  and  can  be  fixed  or  capable  of  rotating; 
 (ii)  section  73.  686(  d)  of  title  47,  Code  of  Federal  Regulations,  should  be  amended  to  create  different  procedures  for  determining  if  the  requisite  digital  signal  strength  is 
 present  than  for  determining  if  the  requisite  analog  signal  strength  is  present  ;  (iii)  a  standard  should  be  used  other  than  the  presence  of  a  signal  of  a  certain  strength  to 
 ensure  that  a  household  can  receive  a  high-  quality  picture  using  antennas  of  reasonable  cost  and  ease  of  installation; 
 (iv)  to  develop  a  predictive  methodology  for  determining  whether  a  household  is  unserved  by  an  adequate  digital  signal  under  section  119(  d)(  10)  of  Title  17,  United 
 States  Code;  (v)  there  is  a  wide  variation  in  the  ability  of  reasonably  priced  consumer  digital 
 television  sets  to  receive  over-  the-  air  signals,  such  that  at  a  given  signal  strength  some  may  be  able  to  display  high-  quality  pictures  while  others  cannot,  whether  such  variation 
 is  related  to  the  price  of  the  television  set,  and  whether  such  variation  should  be  factored  into  setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate 
 digital  signal;  and  (vi)  to  account  for  factors  such  as  building  loss,  external  interference  sources,  or 
 undesired  signals  from  both  digital  television  and  analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets,  foliage,  and  man-  made  clutter. 


 (C)  REPORT-  Not  later  than  one  year  after  the  date  of  the  enactment  of  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004,  the  Federal  Communications 
 Commission  shall  submit  to  the  Committee  on  Energy  and  Commerce  of  the  House  of  Representatives  and  the  Committee  on  Commerce,  Science,  and  Transportation  of  the  Senate 
 a  report  containing  (i)  the  results  of  the  study  under  this  paragraph;  and 
 (ii)  recommendations,  if  any,  as  to  what  changes  should  be  made  to  Federal  statutes  or  regulations. 
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 APPENDIX  B  Parties  Submitting  Comments  and  Reply  Comments 
 Parties  Submitting  Comments 
 1.  ABC,  CBS,  NBC,  Network  Affiliates  2.  The  Association  for  Maximum  Service  Television,  Inc. 
 3.  ATI  Technologies,  Inc.  4.  Consumer  Electronics  Association  (CEA) 
 5.  DIRECTV  Inc.  6.  EchoStar  Satellite  L.  L.  C. 
 7.  National  Association  of  Broadcasters  (NAB)  8.  Paul  Robinson 
 9.  Viamorph 


 Parties  Submitting  Reply  Comments 
 1.  ATI  Technologies,  Inc.,  2.  ABC,  CBS,  and  NBC  Television  Affiliate  Associations 
 3.  Cohen,  Dippell  and  Everist,  P.  C.,  4.  EchoStar  Satellite  L.  L.  C., 
 5.  National  Association  of  Broadcasters 
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 C-  1 
 APPENDIX  C 
 Tests  of  ATSC  8-  VSB  Reception  Performance  of  Consumer  Digital  Television  Receivers 
 Available  in  2005 


 November  2,  2005 


 Technical  Research  Branch  Laboratory  Division 
 Office  of  Engineering  and  Technology  Federal  Communications  Commission 


 OET  Report  Prepared  by:  FCC/  OET  TR  05-  1017  Stephen  R.  Martin 
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 i 
 FOREWORD 
 The  author  gratefully  acknowledges  the  advice  and  technical  support  offered  by  the  following  individuals  and  organizations.  Gary  Sgrignoli  and  Dennis  Wallace  of  MSW  provided  technical  guidance  at  the 


 inception  of  the  project,  and  Gary  Sgrignoli  also  provided  guidance  later  and  reviewed  an  early  draft  of  this  report.  Mark  Hryszko,  Mike  Gittings,  Raul  Casas  of  ATI  Research,  Inc.  identified  degraded 
 performance  of  the  FCCs  RF  capture  player  (which  was  subsequently  repaired  and  calibrated  before  conducting  the  tests  reported  herein)  and  provided  technical  advice;  Mark  Hryszko  and  Kevin  Murr 
 assisted  in  comparative  testing  at  ATIs  laboratory  using  ATIs  equipment  as  a  double-  check  of  the  FCC  equipment  and  measurement  procedures  for  the  FCC  Laboratory  tests  reported  herein.  Wayne  Bretl  of 
 Zenith  Electronics  Corp.  and  Rich  Citta  of  Micronas  Semiconductors,  Inc.  provided  technical  advice  regarding  testing  with  RF  captures.  Victor  Tawil  of  the  Association  for  Maximum  Service  Television 
 (MSTV)  and  Sean  Wallace  of  Wavetech  Services,  LLC  provided  RF  captures  and  technical  advice. 
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 ii 
 TABLE  OF  CONTENTS 
 EXECUTIVE  SUMMARY  .........................................................................................................................  iv  Samples...................................................................................................................................................  iv 


 Test  Results.............................................................................................................................................  iv  CHAPTER  1  INTRODUCTION  ...............................................................................................................  1-  1 
 Background...........................................................................................................................................  1-  1  Objectives  .............................................................................................................................................  1-  1 
 Ability  to  Receive  Signals  ....................................................................................................................  1-  2  Standard  for  Determining  Whether  a  Household  is  Unserved..............................................................  1-  4 
 Overview  ..............................................................................................................................................  1-  4  CHAPTER  2  SCOPE  AND  APPROACH.................................................................................................  2-  1 
 Scope  of  Testing  ...................................................................................................................................  2-  1  Test  Samples.........................................................................................................................................  2-  1 
 Test  Philosophy  and  Approach.............................................................................................................  2-  3  CHAPTER  3  WHITE-  NOISE  THRESHOLD  MEASUREMENTS 
 (REQUIRED  CARRIER-  TO-  NOISE  RATIO)  ....................................................................................  3-  1  Measurement  Method  ...........................................................................................................................  3-  1 
 Format  of  The  Bar  Graph  Data  .............................................................................................................  3-  2  Results  ..................................................................................................................................................  3-  2 
 CHAPTER  4  MINIMUM  INPUT  SIGNAL  MEASUREMENTS  ............................................................  4-  1  Measurement  Method  ...........................................................................................................................  4-  1 
 Results  ..................................................................................................................................................  4-  2  CHAPTER  5  INFERRED  NOISE  FIGURE..............................................................................................  5-  1 
 Results  ..................................................................................................................................................  5-  2  CHAPTER  6  PERFORMANCE  AGAINST  MULTIPATH  USING  FIELD  CAPTURES  ......................  6-  1 
 Measurement  Method  ...........................................................................................................................  6-  1  Results  ..................................................................................................................................................  6-  2 
 CHAPTER  7  INFERRED  PERFORMANCE  AGAINST  REPRESENTATIVE  MULTIPATH  CONDITIONS......................................................................................................................................  7-  1 
 Multipath  Capability  Based  on  Year-  2000  Field  Tests.........................................................................  7-  1  Impact  of  Representative  Multipath  on  Required  CNR........................................................................  7-  2 
 CHAPTER  8  SUMMARY  AND  CONCLUSIONS  ..................................................................................  8-  1  Variation  in  Reception  Performance.....................................................................................................  8-  2 
 Price-  Dependence  of  Reception  Performance  ......................................................................................  8-  3  Reception  Performance  Relative  to  OET-  69  ........................................................................................  8-  3 
 APPENDIX  A:  TEST  CONFIGURATIONS,  ISSUES,  AND  PROCEDURES  ......................................  A-  1  Test  Configurations  .............................................................................................................................  A-  1 
 Calibration  and  Signal  Quality  Tests  on  Test  Setups...........................................................................  A-  2  Test  Issues............................................................................................................................................  A-  4 
 Procedures............................................................................................................................................  A-  6  Equipment..........................................................................................................................................  A-  12 
 APPENDIX  B:  SUMMARY  OF  RF  FIELD  CAPTURES.......................................................................  B-  1 
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 iii 
 ILLUSTRATIONS 
 Figure  3-  1.  Measured  White  Noise  Threshold  of  Receivers.....................................................................  3-  6  Figure  4-  1.  Measured  Minimum  Signal  Level  at  TOV  on  Three  Channels..............................................  4-  5 


 Figure  4-  2.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  3  (Low  VHF)...................................  4-  5  Figure  4-  3.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  10  (High  VHF)................................  4-  6 
 Figure  4-  4.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  30  (UHF).........................................  4-  6  Figure  4-  5.  Measured  Minimum  Signal  Level  at  TOV  Versus  Channel  for  Receiver  G2........................  4-  7 
 Figure  4-  6.  Measured  Minimum  Signal  Level  at  TOV  Versus  Frequency  for  Receiver  G2  ....................  4-  7  Figure  5-  1.  Relationship  between  Minimum  Signal  at  TOV  and  Required  CNR.....................................  5-  5 
 Figure  5-  2.  Noise  Figure  on  Three  Channels............................................................................................  5-  5  Figure  5-  3.  Noise  Figure  on  Channel  3  (Low  VHF).................................................................................  5-  6 
 Figure  5-  4.  Noise  Figure  on  Channel  10  (High  VHF)  ..............................................................................  5-  6  Figure  5-  5.  Noise  Figure  on  Channel  30  (UHF)  .......................................................................................  5-  7 
 Figure  5-  6.  Required  CNR  Versus  Noise  Figure  ......................................................................................  5-  7  Figure  6-  1.  Performance  Against  47  RF  Captures  ....................................................................................  6-  6 
 Figure  6-  2.  White  Noise  Threshold  Versus  Multipath  Performance  ........................................................  6-  6  Figure  A-  1.  Block  Diagram  of  Test  Configuration  for  Required  CNR  and  RF  Capture  Tests..............  A-  13 
 Figure  A-  2.  Block  Diagram  of  Test  Configuration  for  Minimum  Signal  at  TOV  .................................  A-  13  Figure  A-  3.  Frequency  Response  of  Each  Port......................................................................................  A-  14 
 Figure  A-  4.  Effect  of  Load  Impedance  Mismatch  .................................................................................  A-  14  Figure  A-  5.  Calibration  Connection  for  Test  Setup  for  Required  CNR  and  RF  Capture  Tests.............  A-  15 
 Figure  A-  6.  Spectra  of  Injected  Signal  and  Noise  at  15-  dB  CNR  .........................................................  A-  15 


 TABLES 
 Table  1-  1.  Planning  Factors  for  DTV  Reception  Prediction.....................................................................  1-  4  Table  2-  1.  DTV  Receiver  Samples  ...........................................................................................................  2-  3 


 Table  3-  1.  Statistics  of  White  Noise  Threshold  ........................................................................................  3-  3  Table  3-  2.  Product-  Type/  Price  Variations  of  White  Noise  Threshold......................................................  3-  4 
 Table  3-  3.  Correlation  Coefficient  of  White  Noise  Threshold  with  Price  ................................................  3-  4  Table  4-  1.  Statistics  of  Minimum  Signal  Level  at  TOV  ...........................................................................  4-  2 
 Table  4-  2.  Product-  Type/  Price  Variations  of  Minimum  Signal  at  TOV...................................................  4-  4  Table  4-  3.  Correlation  Coefficient  of  Minimum  Signal  at  TOV  with  Price  .............................................  4-  4 
 Table  5-  1.  Statistics  of  Receiver  Noise  Figure  .........................................................................................  5-  2  Table  5-  2.  Product-  Type/  Price  Variations  of  Receiver  Noise  Figure  .......................................................  5-  3 
 Table  5-  3.  Correlation  Coefficient  of  Receiver  Noise  Figure  with  Price..................................................  5-  4  Table  6-  1.  Number  of  Captures  Successfully  Played  By  Each  Performance  Tier  ....................................  6-  3 
 Table  8-  1.  Net  Performance  for  Unimpaired  Signal  Relative  to  OET-  69  Model  .....................................  8-  4  Table  8-  2.  Planning  Factor  Measurements  with  Unimpaired  Signal  ........................................................  8-  4 
 Table  A-  1.  Equipment  List  ....................................................................................................................  A-  12  Table  B-  1.  RF  Field  Captures  ..................................................................................................................  B-  2 
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 iv 
 EXECUTIVE  SUMMARY 
 This  report  presents  the  results  of  laboratory  tests  of  over-  the-  air  digital  (ATSC/  8-  VSB  *  )  reception  performance  of  28  consumer  digital  television  (DTV)  receivers.  The  tests  were  performed  to  provide  an 


 empirical  basis  for  answering  questions  about  DTV  reception  capability  that  derive  from  study  requirements  imposed  by  Congress  as  part  of  the  Satellite  Home  Viewer  Extension  and  Reauthorization 
 Act  of  2004  (SHVERA).  The  Act  requires  that  the  FCC  conduct  a  six-  element  study.  The  element  relevant  to  this  report  is  as  follows: 
 consider  whether    there  is  a  wide  variation  in  the  ability  of  reasonably-  priced  consumer  digital  television  sets  to  receive  over-  the-  air  signals,  such  that  at  a  given  signal  strength  some 
 may  be  able  to  display  high-  quality  pictures  while  others  cannot,  whether  such  variation  is  related  to  the  price  of  the  television  set,  and  whether  such  variation  should  be  factored  into 
 setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate  digital  signal. 


 SAMPLES 
 Two  categories  of  DTV  receivers  were  acquired  for  this  project:  digital  set-  top  boxes  (STBs)  and  DTVs  with  integrated  over-  the-  air  ATSC  tuners.  All  receivers  are  standard,  off-  the-  shelf  consumer  products 


 currently  on  the  market.  STBs  were  included  in  the  study  because  connection  of  an  STB  to  an  existing  television  represents  the  lowest-  cost  alternative  for  DTV  reception.  The  measurement  results  in  this 
 document  are  reported  by  category  (STB  or  integrated  DTVs)  and,  within  the  DTV  category,  by  price  range  ($  370  -  $1000,  $1001  -  $2000,  and  $2001  -  $4200).  Brands  and  model  numbers  are  not  reported. 


 TEST  RESULTS 
 The  tests  performed  for  this  report  were  laboratory-  based  measurements  emulating  two  types  of  over-  the-air  reception  conditions  for  DTV  receivers: 


 (1)  Unimpaired  signal  (i.  e.,  no  multipath)  [Chapters  3    5],  and 
 (2)  Signal  impaired  by  multipath  (ghosts)  [Chapter  6]. 
 The  unimpaired  signal  measurements  can  be  used  to  quantitatively  predict  receiver  performance  under  benign  reception  conditions  i.  e.,  with  little  multipath  or  interference.  The  multipath  tests,  which  focus 


 primarily  on  particularly  difficult  multipath  conditions,  provide  a  basis  for  comparing  the  ability  of  different  DTV  receivers  to  handle  difficult  multipath  conditions.  A  link  between  these  laboratory-  based 
 measurements  and  earlier  FCC  field-  test  data  provides  a  basis  for  anchoring  the  multipath  results  to  representative,  real-  world  reception  conditions  [Chapter  7]. 


 Benign  Multipath  Conditions 
 Overall  performance  under  benign  reception  conditions  is  indicated  by  minimum  signal  level  at  the  threshold  of  visibility  of  errors  (TOV)  for  each  receiver.  The  median  measured  values  of  this  parameter 


 across  all  of  the  tested  consumer  DTV  receivers  were  -82.2  dBm,  -83.2  dBm,  and  -83.9  dBm,  respectively,  in  the  low-  VHF,  high-  VHF,  and  UHF  bands.  These  values  comply,  within  measurement 
 accuracy,  with  the  -83  dBm  minimum  performance  standard  recommended  by  the  ATSC.  The  corresponding  medians  for  just  the  low-  cost  category  of  DTVs  (-  83.3  dBm,  -83.4  dBm,  and  -84.1  dBm, 
 respectively)  were  very  slightly  better  than  the  medians  across  all  of  the  receiver  categories. 
 *  8-  level  Vestigial  Side  Band  (8-  VSB)  is  the  over-  the-  air  digital  television  (DTV)  transmission  format 
 recommended  by  the  Advanced  Television  Systems  Committee  (ATSC)  and  adopted  by  the  FCC  as  the  U.  S.  standard  for  terrestrial  DTV  transmission. 
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 v 
 OET  Bulletin  No.  69,  Longley-  Rice  Methodology  for  Evaluating  TV  Coverage  and  Interference,  presents  a  methodology  for  predicting  whether  a  household  is  served  by  a  given  broadcast  signal.  The 
 DTV  receiver  model  in  that  bulletin  predicts  minimum  signal  levels  at  TOV  of  -81.0  dBm  and  -84.0  dBm  for  VHF  and  UHF,  respectively.  While  the  test  results  presented  in  this  report  together  with  data  based 
 on  earlier  FCC  field  tests  could  be  used  to  fine  tune  those  parameters,  the  net  effect  of  such  changes  would  be  small;  consequently,  no  compelling  reason  is  seen  for  such  fine  tuning. 


 Variation  in  minimum  signal  at  TOV  among  the  receivers  was  found  to  be  moderately  high  in  the  low-VHF  band,  but  small  in  the  high-  VHF  and  UHF  bands. 
 In  the  low  VHF  band  (as  represented  by  TV  channel  3  in  these  tests),  the  moderately  high  variability  in  performance  among  the  samples  is  indicated  by  the  3.7-  dB  standard  deviation  among  the  receivers  and 
 the  fact  that  two  same-  brand  receivers  exhibited  performance  significantly  worse  than  the  median  by  11  and  12  dB.  (It  is  noted  that,  absent  those  two  receivers,  the  standard  deviation  would  have  been  a  more 
 modest  2.3  dB.) 
 Though  the  performance  variation  among  the  receivers  in  the  low  VHF  band  was  moderately  high,  no  statistically  significant  price-  dependence  of  that  variation  was  found.  In  fact,  the  median  performance  of 
 the  low-  cost  TVs  was  slightly  better  than  that  of  either  the  mid-  priced  or  high-  priced  TVs.  The  median  performance  of  the  tested  set-  top  boxes  was  poorer  than  that  of  the  integrated  DTVs  by  2.3  dB,  though  it 
 must  be  noted  that  these  were  older  designs  (2004  and  earlier  models  that  were  still  on  the  market  at  the  time  of  this  report)  than  the  integrated  DTVs. 


 In  the  high-  VHF  and  the  UHF  bands  (represented  in  the  tests  by  channels  10  and  30,  respectively),  the  variation  in  reception  performance  among  the  tested  receivers  was  small  as  indicated  by  the  1.6-  dB 
 standard  deviation  in  the  high-  VHF  band  and  0.9  dB  in  the  UHF  band.  The  variation  of  performance  with  price  was  judged  to  be  both  small  and  not  statistically  significant.  The  median  performance  of  the 
 high-  cost  TVs  differed  from  that  of  the  low-  cost  TVs  by  less  that  0.2  dB.  Set  top  boxes  exhibited  median  performance  0.6  dB  and  0.7  dB  worse  than  the  median  of  all  TVs  in  the  low-  VHF  and  UHF  bands, 
 respectively. 
 Most  of  the  variation  in  reception  performance  among  the  tested  receivers  was  due  to  differences  in  effective  noise  figure  rather  than  in  the  carrier-  to-  noise  ratio  (CNR)  required  for  successful  demodulation. 
 The  noise  figure  variations  were  larger  than  the  required-  CNR  variations  by  factors  ranging  from  4,  in  the  UHF  band,  to  16,  in  the  low-  VHF  band. 


 Difficult  Multipath  Conditions 
 The  tested  receivers  fall  into  two  distinct  tiers  of  multipath-  handling  capability  the  upper  tier  representing  a  significant  performance  improvement  associated  with  at  least  two  companies  newest 


 generation  of  demodulator  chips.  While  the  difference  in  ability  to  handle  difficult  multipath  conditions  between  the  two  tiers  is  large,  linkage  of  the  current  results  with  earlier  field  test  results  (Chapter  7) 
 suggests  that  the  observed  performance  differences  are  of  no  consequence  in  the  vast  majority  of  reception  locations,  if  an  outdoor,  mast-  mounted  antenna  is  used.  When  an  indoor  antenna  is  used,  the 
 linkage  suggests  that  the  observed  performance  differences  would  be  significant  in  many,  but  probably  not  most,  locations. 


 Given  that  both  tiers  of  performance  appeared  in  all  three  price  ranges  of  DTVs,  there  appears  to  be  no  price  dependence  of  multipath  performance;  however,  there  was  a  complete  absence  of  upper-  tier 
 performers  among  the  tested  set-  top  boxes.  This  absence  is  attributed  to  the  older  designs  of  the  set-  top  box  products  all  of  which  were  introduced  in  the  year  2004  or  earlier.  Among  the  tested  DTV  receivers, 
 none  that  were  introduced  before  March  2005  were  found  to  exhibit  upper-  tier  performance,  whereas  48  percent  of  those  introduced  in  or  after  that  month  performed  at  the  upper  tier  level. 
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 CHAPTER  1  INTRODUCTION 
 BACKGROUND 
 This  report  presents  the  results  of  laboratory  tests  of  terrestrial  over-  the-  air  digital  (ATSC/  8-  VSB  *  )  reception  performance  of  28  consumer  digital  television  (DTV)  receivers.  Though  the  tests  involve 


 terrestrial  reception  performance,  the  tests  were  performed  to  provide  an  empirical  basis  for  answering  questions  about  DTV  reception  capability  that  derive  from  study  requirements  imposed  by  Congress  as 
 part  of  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004  (SHVERA). 
 SHVERA,  passed  by  Congress  in  December  2004,  extends  and  amends  the  Satellite  Home  Viewer  Act  of  1994.  The  Act  allows  satellite  communications  providers  to  provide  broadcast  programming  to  satellite 
 subscribers  that  are  unserved  by  local  over-  the-  air  broadcast  stations. 
 Section  204  of  SHVERA  requires  that  the  Commission  conduct  an  inquiry  regarding  whether,  for  purposes  of  identifying  if  a  household  is  unserved  by  an  adequate  digital  signal  under  section  119(  d)(  10) 
 of  title  17,  United  States  Code,  the  digital  signal  strength  standard  in  section  73.622(  e)(  1)  of  title  47,  Code  of  Federal  Regulations,  or  the  testing  procedures  in  section  73.686(  d)  of  title  47,  Code  of  Federal 
 Regulations,  such  statutes  or  regulations  should  be  revised  to  take  into  account  the  types  of  antennas  that  are  available  to  consumers. 


 The  act  specifies  six  areas  of  inquiry.  The  relevant  area  for  this  report  is  the  one  that  relates  to  characteristics  of  consumer  digital  television  receivers.  It  states  that  the  inquiry  should 
 consider  whether    there  is  a  wide  variation  in  the  ability  of  reasonably-  priced  consumer  digital  television  sets  to  receive  over-  the-  air  signals,  such  that  at  a  given  signal  strength  some 
 may  be  able  to  display  high-  quality  pictures  while  others  cannot,  whether  such  variation  is  related  to  the  price  of  the  television  set,  and  whether  such  variation  should  be  factored  into 
 setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate  digital  signal. 


 The  Act  requires  that  the  results  and  recommendations  from  this  inquiry  be  reported  to  the  Committee  on  Energy  and  Commerce  of  the  House  of  Representatives  and  the  Committee  on  Commerce,  Science,  and 
 Transportation  of  the  Senate. 


 OBJECTIVES 
 This  report  presents  the  results  of  a  measurement  program  that  was  undertaken  by  the  Technical  Research  Branch  of  the  FCC  Laboratory  in  order  to  address  those  portions  of  the  SHVERA-  required  inquiry  that 


 involve  characteristics  of  consumer  digital  television  receivers.  Accordingly,  the  objectives  are  to  provide  an  empirical  basis  for  answering  three  questions. 


 *  8-  level  Vestigial  Side  Band  (8-  VSB)  is  the  over-  the-  air  digital  television  (DTV)  transmission  method 
 recommended  by  the  Advanced  Television  Systems  Committee  (ATSC)  and  adopted  by  the  FCC  as  the  U.  S.  standard  for  terrestrial  DTV  transmission. 
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 (1)  Is  there  a  wide  variation  in  the  ability  of  reasonably-  priced  consumer  digital  television  sets  to  receive  over-  the-  air  signals,  such  that  at  a  given  signal  strength  some  may  be  able  to  display  high-  quality  pictures 
 while  others  cannot?  (2)  Is  such  variation  is  related  to  the  price  of  the  television  set? 
 (3)  Should  such  variation  be  factored  into  setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate  digital  signal. 


 ABILITY  TO  RECEIVE  SIGNALS 
 The  ability  of  a  television  receiver  to  receive  over-  the-  air  signals  and  display  a  high  quality  picture  is  influenced  by  the  level  and  quality  of  the  television  signal  reaching  its  antenna  input  terminal  from  the 


 antenna  downlead,  the  amount  of  noise  or  interference  reaching  the  input  terminal,  and  the  properties  of  the  television  receiver  including  the  amount  of  noise  created  by  the  input  circuitry  of  the  television 
 receiver. 


 Threshold 
 When  a  television  receives  a  signal  from  an  analog  TV  station  using  the  NTSC  transmission  system  that  has  been  employed  in  the  U.  S.  for  decades,  the  TV  exhibits  a  noisy  picture  at  low  signal  levels.  The  noise 


 is  frequently  termed  snow.  If  the  signal  level  increases,  the  amount  of  snow  in  the  picture  decreases  very  gradually.  If  signal  level  is  increased  until  it  exceeds  the  internally  generated  noise  of  the 
 televisions  input  circuits  by  34  dB  (carrier-  to-  noise  ratio  =  34  dB),  the  picture  level  improves  to  the  point  that  typical  viewers  consider  the  noise  to  be  slightly  annoying.  *  The  noise  remains  perceptible  but  is 
 not  considered  annoying  at  a  40-  43  dB  carrier-  to-  noise  ratio,    and  ceases  to  be  visible  at  all  when  the  carrier-  to-  noise  ratio  (CNR)  is  51  dB.   


 When  a  digital  television  receives  a  signal  from  a  digital  television  station  using  the  ATSC  transmission  system  adopted  by  the  FCC  for  terrestrial  DTV  broadcasts  in  the  U.  S.,  the  transition  from  no  picture  to  a 
 virtually  perfect  picture  occurs  over  a  much  narrower  range  of  signal  levels.  Once  a  threshold  signal  level  is  reached,  the  TV  picture  is  virtually  perfect  limited  only  by  the  quality  of  the  source  material  and  the 
 characteristics  of  the  television  display  (for  example,  the  picture  tube  and  associated  image  forming  circuits  and  software).  This  threshold  corresponds  to  a  carrier-  to-  noise  ratio  of  only  about  15  dB.  If  the 
 signal  is  reduced  below  this  threshold  value,  visible  errors  begin  to  occur  in  the  picture  becoming  more  frequent  with  further  reductions  in  signal  level,  until  the  picture  becomes  essentially  unusable  at  a  level 
 only  about  1  dB  below  the  threshold. 
 Part  of  the  task  of  determining  the  ability  of  a  DTV  receiver  to  receive  over-  the-  air  signals  is  to  determine  this  threshold  when  only  a  DTV  signal  is  applied  to  the  antenna  terminal  (i.  e.,  without  any  noise  or 
 interfering  signals),  as  well  as  when  both  a  DTV  signal  and  source  of  electronic  noise  are  applied  simultaneously  to  the  antenna  terminal.  The  resulting  measured  parameters  are  the  minimum  signal  at  the 
 threshold  of  visibility  of  errors  (TOV)  and  the  white  noise  threshold  also  known  as  the  required  carrier-to-  noise  ratio  (CNR). 


 *  Citta,  Richard,  and  Sgrignoli,  Gary,  ATSC  Transmission  System:  VSB  Tutorial,  Montreuz  Symposium,  June 
 12,  1997,  p.  8. 
   Sgrignoli,  Gary,  Interference  Analysis  of  Co-  Sited  DTV  and  NTSC  Translators,  IEEE  Transactions  on 
 Broadcasting,  Vol.  51,  No.  1,  March  2005,  p.  3. 
   Eilers,  Carl,  and  Sgrignoli,  Gary,  Digital  Television  Transmission  Parameters--  ATSC  Compliance  Factors, 
 IEEE  Transactions  on  Broadcasting,  Vol.  45,  No.  4,  December  1999,  p.  12. 
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 Multipath 
 A  propagation  phenomenon  called  multipath  causes  very  different  effects  for  analog  versus  digital  television  transmissions.  Multipath  is  caused  by  the  fact  that  the  broadcast  signal  may  reach  the 


 television  antenna  through  several  propagation  paths  that  reflect  off  of  various  natural  and  man-  made  objects.  A  direct  signal  path  encountering  no  reflections  may  also  be  present.  The  reflected  signal  paths 
 are  essentially  delayed  versions  of  the  direct-  path  signal  with  the  delay  being  dependent  on  the  additional  distance  traveled  by  each  reflected  signal. 


 With  analog  (NTSC)  television,  multipath  causes  one  or  more  ghost  images  displaced  horizontally  from  the  main  image.  (The  term  ghost  refers  to  the  ghost-  like  appearance  of  the  displaced  image,  which 
 appears  as  a  fainter  version  of  the  primary  image.)  Ghosts  can  significantly  degrade  picture  quality  even  when  the  primary  signal  strength  is  quite  high.  In  analog  television,  control  of  ghosts  is  usually 
 accomplished  by  using  a  directional  antenna  oriented  to  selectively  receive  the  stronger  signal  (usually  the  direct  path  signal)  and  to  reject  at  least  to  some  extent  other  paths,  for  which  signals  typically  arrive 
 from  other  directions. 
 With  digital  (ATSC)  television,  multipath  does  not  cause  ghost-  like  displaced  images  on  the  screen,  though  the  term  ghost  is  still  used  to  describe  multipath  propagation.  Instead,  a  weak  ghost  may  have 
 no  effect  on  the  picture  at  all.  A  somewhat  stronger  ghost  may  cause  picture  impairments  such  as  blockiness  or  freeze  frames.  An  even  stronger  ghost  can  completely  prevent  the  television  from  decoding 
 the  digital  data  necessary  to  produce  a  picture  and  sound.  Consequently,  all  ATSC  television  receivers  contain  a  circuit  called  an  equalizer,  the  function  of  which  is  to  adaptively  cancel  ghosts.  If  the  equalizer 
 reduces  the  amplitudes  of  all  but  one  signal  path  to  a  sufficiently  low  level,  the  picture  will  be  displayed  with  no  impairment  at  all.  If  the  cancellation  is  insufficient,  the  TV  may  fail  to  produce  a  picture  even 
 when  signal  level  is  very  strong. 
 Equalizer  performance  has  been  one  of  the  primary  areas  of  technological  improvement  as  DTV  receivers  progress  from  one  generation  to  the  next.  With  advances  in  equalizer  technology,  significant 
 improvements  have  been  made  in  the  ability  to  cancel  larger  amplitude  ghosts,  ghosts  with  larger  delays  relative  to  the  main  signal,  and  ghost  signals  arriving  earlier  than  the  main  signal  (in  cases  for  which  the 
 direct  path  signal  is  either  absent  or  weaker  than  reflected  signals).  Other  researchers  have  noted  a  high  degree  of  improvement  in  multipath-  handling  capability  of  the  latest  generation  of  equalizer  technology.  * 


 Consequently,  a  part  of  determining  the  ability  of  a  DTV  receiver  to  receive  over-  the-  air  signals  is  to  characterize  the  ability  of  the  receiver  to  handle  various  multipath  conditions.  For  this  study,  that 
 characterization  was  performed  by  feeding  the  antenna  input  terminal  of  the  TV  with  signals  that  were  recorded  from  television  antennas  at  various  locations  in  New  York  City  and  Washington,  D.  C. 


 It  is  also  noted  that,  for  DTV  receivers  that  are  compliant  with  the  EIA/  CEA-  909  Antenna  Control  Interface  specification,  smart  antenna  technology  can  mitigate  the  effects  of  multipath,  as  well  as  certain 
 other  reception  issues,  through  automatic  optimization  of  various  antenna  parameters  such  as  the  effective  pointing  direction,  polarization,  and  amplifier  gain  on  a  per-  channel  basis.  The  ATSC,  in  its  ATSC 
 Recommended  Practice:  Receiver  Performance  Guidelines,  recommends  that  in  addition  to  the  other  guidelines  contained  herein  for  the  handling  of  signal  conditions  that  are  experienced  in  the  field, 
 consideration  of  a  receiver-  controlled  antenna,  as  enabled  by  CEA-  909,  is  recommended  and  notes  that  such  a  controllable  antenna  can  work  in  conjunction  with  a  receivers  equalizer,  tuner,  and  demodulator 
 to  improve  reception  under  conditions  of  multipath  and  unusually  weak  or  strong  signals.    This  interface 
 *  Laud,  Tim,  Aitken,  Mark;  Bretl,  Wayne;  and  Kwak,  K.  Y.,  Performance  of  5th  Generation  8-  VSB  Receivers, 
 IEEE  Transactions  on  Consumer  Electronics,  Vol.  50,  No.  4,  November  2004. 
   ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced  Television 
 Systems  Committee,  17  June  2004,  p.  24. 
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 was  included  in  only  one  of  the  DTV  receivers  tested  for  this  report.  Though  the  smart  antenna  functionality  was  not  formally  tested,  we  observed  that  it  did  offer  a  user-  friendly  way  to  optimize  TV 
 reception.  Not  only  does  it  simplify  the  initial  setup  of  the  DTV  for  the  consumer,  but  it  also  provides  the  advantage  of  instantaneously  switching  the  antenna  pointing  direction  electronically  whenever  the  TV 
 channel  is  changed. 


 STANDARD  FOR  DETERMINING  WHETHER  A  HOUSEHOLD  IS  UNSERVED 
 Section  73.622(  e)  of  the  Commissions  rules,  Code  of  Federal  Regulations  (CFR)  47,  specifies  a  method  for  determining  the  service  area  of  a  DTV  broadcast  station  based  on  OET  Bulletin  No.  69,  Longley-Rice 
 Methodology  for  Evaluating  TV  Coverage  and  Interference  hereafter  referred  to  as  OET-  69.  The  bulletin  defines  the  method  for  predicting  field  strength  created  at  any  given  location  by  a  television 
 transmitter.  It  further  defines  television  reception  system  planning  factors  that  can  be  used  to  determine  the  field  strength  required  for  successful  DTV  reception. 


 The  FCCs  defined  reception  planning  factors  include  antenna  gain,  signal  loss  in  the  down-  lead  cable  connecting  the  antenna  to  the  television  receiver,  noise  figure  of  the  receiver,  and  required  carrier-  to-  noise 
 ratio.  The  latter  two  factors  are  functions  of  the  DTV  receiver  and  are  a  primary  focus  of  the  measurements  conducted  for  this  report.  These  parameters,  as  specified  by  OET-  69,  are  shown  in 
 Table  1-  1. 


 Table  1-  1.  Planning  Factors  for  DTV  Reception  Prediction 
 Planning  Factor  Symbol  Low  VHF  High  VHF  UHF  Geometric  Mean  Frequency  (MHz)  F  69  194  615 


 System  noise  figure  (dB)  NS  10  10  7  Required  Carrier-  to-  Noise  ratio  (dB)  C/  N  15.2  (15)  15.2  (15)  15.2  (15) 
 Note:  The  Final  Technical  Report  of  the  FCC  Advisory  Committee  on  Advanced  Television  Service  listed  15.19  dB  as  the  C/  N  for  the  Grand  Alliance  DTV  receiver.  *  In  OET-  69  this  value  is 
 rounded  to  the  nearest  dB  i.  e.,  15  dB;  however,  in  identifying  OET-  69  planning  factors  and  predictions  for  this  report,  we  will  round  to  the  nearest  tenth  of  a  dB  and  use  15.2  dB.  Combining 
 this  C/  N  value  with  the  system  noise  figures  and  the  -106.2  dBm  thermal  noise  level  specified  in  OET-  69,  yields  a  minimum  signal  power  at  TOV  of  -81.  0  dBm  in  VHF  and  -84.0  dBm  in  UHF. 


 Although  OET-  69  was  developed  for  defining  service  areas  for  channel-  allocation  purposes,  the  same  approach  could  be  used  for  initial  prediction  of  whether  a  household  is  unserved  by  an  adequate  digital 
 signal  for  SHVERA  purposes.  Consequently,  this  report  will  evaluate  the  validity  of  the  OET-  69  planning  factors  based  on  measurements  of  current-  model  consumer  DTVs. 


 OVERVIEW 
 The  laboratory-  based  measurements  performed  for  this  report  emulated  two  types  of  over-  the-  air  reception  conditions  for  DTV  receivers: 


 (1)  Unimpaired  signal  (i.  e.,  no  multipath)  [Chapters  3    5],  and 
 (2)  Signal  impaired  by  multipath  (ghosts)  [Chapter  6]  focusing  on  particularly  difficult  multipath  conditions. 


 *  Final  Technical  Report,  FCC  Advisory  Committee  on  Advanced  Television  Services  (ACATS),  October  31, 
 1995,  p.  15  (Table  5.1). 
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 The  unimpaired  signal  measurements  can  be  used  to  quantitatively  predict  receiver  performance  under  benign  reception  conditions  i.  e.,  with  little  multipath  (commonly  referred  to  as  a  white  Gaussian 
 channel).  The  multipath  tests  provide  a  basis  for  comparing  the  ability  of  different  DTV  receivers  to  handle  difficult  multipath  conditions.  Chapter  7  links  the  new,  laboratory-  based  measurements  to  earlier 
 FCC  field-  test  data  as  a  basis  for  anchoring  the  multipath  results  to  representative,  real-  world  reception  conditions. 
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 CHAPTER  2  SCOPE  AND  APPROACH 
 SCOPE  OF  TESTING 
 The  parameters  measured  for  this  report  to  characterize  each  television  receiver  are  as  follows:  (1)  minimum  signal  at  the  threshold  of  visibility  of  errors  (TOV); 


 (2)  the  white  noise  threshold  (defined  at  the  TOV)  also  known  as  the  required  carrier-  to-  noise  ratio  (CNR);  and, 
 (3)  the  number  of  ATSC-  recommended  field  ensembles  (RF  captures)  that  can  be  successfully  demodulated  by  the  receiver. 


 The  first  two  of  these  are  measures  of  sensitivity  of  the  receiver  for  an  unimpaired  signal.  The  latter  characterizes  the  ability  of  the  receiver  to  handle  difficult  multipath  conditions. 
 While  these  measurements  provide  a  basis  for  achieving  the  stated  objectives  of  this  report,  it  should  be  recognized  that  they  do  not  fully  characterize  the  over-  the-  air  reception  capability  of  a  DTV  receiver. 
 The  ATSC  recommends  that  DTV  receivers  be  evaluated  on  the  basis  of  a  wide  variety  of  criteria  that  are  not  included  in  this  report,  such  as  multi-  signal  overload,  tolerance  to  phase  noise,  co-  channel  rejection, 
 adjacent-  channel  rejection,  burst  noise  rejection,  and  a  more  complete  characterization  of  multipath  capability.  * 


 TEST  SAMPLES 
 Given  the  objectives  of  determining  whether  there  is  a  wide  variation  in  reception  performance  of  reasonably-  priced  consumer  digital  television  receivers  and  determining  whether  the  variation  is  related  to 


 price  of  the  receiver,  an  effort  was  made  to  select  samples  over  a  range  of  prices,  but  with  emphasis  on  the  lower  end  of  the  price  range. 


 Two  categories  of  DTV  receivers  were  acquired  for  this  project:  digital  set-  top  boxes  (STBs)  and  DTVs  with  integrated  over-  the-  air  ATSC  tuners.  The  selected  receivers  are  standard,  off-  the-  shelf  consumer 
 products  currently  on  the  market. 
 STBs  were  included  in  the  study  because  connection  of  a  set-  top  box  to  an  existing  television  represents  the  lowest-  cost  alternative  for  DTV  reception.  Each  STB  includes  a  digital  tuner  and  outputs  necessary  to 
 drive  high-  definition  television  displays  (through  component  video,  DVI,  or  HDMI  connections)  and  standard-  resolution  analog  televisions  (through  a  composite  video  output  or  an  S-  Video  [Y-  C]  output). 
 When  driving  a  conventional  analog  television,  high  definition  programming  is  down-  converted  to  the  resolution  of  the  TV.  Besides  their  use  in  enabling  digital  reception  with  analog  TVs,  set-  top  boxes  are 
 also  useful  to  consumers  who  have  high-  definition,  digital-  ready  televisions  that  do  not  include  an  ATSC  tuner. 


 *  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced  Television 
 Systems  Committee,  17  June  2004. 
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 Selection  Criteria 
 In  selecting  receivers  for  this  study,  several  criteria  were  applied. 


 1.  A  total  of  about  30  samples  was  planned  for  the  tests  in  order  to  balance  the  need  for  a  large  enough  sample  to  provide  a  degree  of  statistical  confidence  in  the  results  with  the  need  to  limit  sample  size  for 
 practical  reasons. 
 2.  Recently  introduced  models  were  selected,  where  possible,  especially  if  the  manufacturer  expected  a  change  in  over-  the-  air  digital  reception  performance  with  the  newer  model;  in  some  cases  this  meant 
 requesting  a  model  that  was  not  available  when  the  tests  were  begun,  but  was  delivered  late  in  the  test  cycle  or,  in  two  cases,  was  delivered  too  late  to  include  in  this  report. 


 3.  An  attempt  was  made  to  obtain  one  set-  top  box  from  most  companies  that  manufacture  one.  (All  set-top  box  models  were  of  relatively  old  designs  introduced  in  the  year  2004  or,  in  one  case,  2003  even 
 though  they  were  the  latest  models  available  on  the  market.) 
 4.  One  DTV  having  an  integrated  ATSC  tuner  was  selected  from  at  or  near  the  low-  price  end  of  each  manufacturers  product  line. 


 5.  In  addition,  a  mid  or  mid-  to-  high  priced  DTV  having  an  integrated  ATSC  tuner  was  requested  from  many  of  the  manufacturers. 


 Overview  of  the  Samples 
 Table  2-  1  summarizes  the  characteristics  of  the  DTV  receivers  in  the  test  sample.  The  receivers,  which  represent  16  brand  names,  are  divided  by  product  type  set-  top  box  versus  DTV  with  integrated  ATSC 


 tuner  and,  within  the  DTV  type,  by  price  range.  In  most  cases,  prices  were  determined  by  selecting  the  median  price  from  a  FROOGLE  search  for  each  product  conducted  in  August,  2005.  Four  products  not 
 found  through  FROOGLE  were  priced  through  Wal-  Mart  in  August,  2005,  and  one  was  priced  through  Amazon  in  September,  2005. 
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 Other  tests,  for  which  results  were  not  expected  to  vary  with  channel,  were  performed  on  TV  channel  30. 
 Operation  and  Connection  of  Samples 
 For  receivers  having  multiple  antenna  inputs  that  could  handle  ATSC  signals,  only  the  input  labeled  antenna  A  or  antenna  1  was  tested.  For  receivers  having  a  radio  frequency  (RF)  output  associated 


 with  the  selected  antenna  input,  the  output  was  externally  terminated  in  75  ohms. 
 Each  set-  top  box  was  operated  in  a  high  definition  mode  and  was  connected  to  a  high  definition  monitor  by  means  of  a  component  video  output. 


 Test  Configurations 
 All  test  and  measurement  setups  maintained  a  50-  ohm  impedance  throughout,  except  at  the  signal  source  and  the  consumer  TV  inputs,  which  were  each  specified  to  be  nominally  75  ohms.  (An  older, 


 instrumented  reference  receiver  included  in  one  test  had  a  50-  ohm  input  impedance.)  The  75-  ohm  devices  were  matched  to  the  rest  of  the  test  setup  through  impedance-  matching  pads,  except  that,  for  one 
 of  the  test  setups,  an  impedance  transformer  was  used  at  the  signal  source  to  reduce  losses.  In  addition  to  the  impedance-  matching  pads,  50-  ohm  attenuator  pads  were  used  at  various  places  throughout  the  test 
 setups  to  reduce  the  effects  of  any  impedance  mismatches  at  places  where  such  mismatches  were  considered  likely  or  would  be  expected  to  have  a  significant  impact. 


 The  minimum  signal  at  TOV  is  the  only  measured  parameter  for  which  absolute  accuracy  of  the  measurement  equipment  was  a  factor;  consequently,  that  parameter  was  tested  by  connecting  a  signal 
 source  through  appropriate  pads,  step  attenuators,  and  cables  to  one  TV  at  a  time.  After  adjusting  the  signal  attenuation  to  achieve  TOV  on  the  TV,  the  output  of  the  entire  setup  with  the  exception  of  the 
 final  impedance-  matching  pad,  was  connected  to  a  vector  signal  analyzer  for  measurement  of  the  signal  level.  The  only  correction  then  necessary  to  determine  the  input  to  the  TV  was  to  subtract  the  attenuation 
 of  the  impedance-  matching  pad  from  the  measured  level.  That  attenuation  was  measured  separately. 
 For  the  measuring  white  noise  threshold  (required  CNR),  absolute  measurement  accuracy  was  less  critical  since  the  value  to  be  determined  was  the  ratio  of  a  signal  level  to  a  noise  level.  To  maintain  accuracy  of 
 the  ratio,  both  measurements  were  made  with  the  vector  signal  analyzer  on  the  same  amplitude  range.  The  reduced  criticality  of  absolute  measurement  accuracy  enabled  the  use  of  a  splitter  to  simultaneously 
 deliver  the  signal  and  noise  to  as  many  as  eight  TVs  and  to  the  vector  signal  analyzer  for  the  quantitative  measurements.  The  simultaneous  connection  reduced  measurement  time  by  allowing  TV  channel  scans 
 (required  by  many  of  the  TVs  when  a  signal  was  changed)  to  be  performed  simultaneously  on  multiple  TVs  and  by  reducing  the  need  to  repeatedly  disconnect  and  reconnect  cables. 


 Tests  of  the  ability  of  each  receiver  to  handle  the  multipath  conditions  represented  by  the  ATSC-recommended  field  ensembles  (RF  captures)  also  did  not  require  absolute  accuracy  in  measuring  the 
 applied  signal  levels;  consequently,  the  same  splitter  arrangement  was  used.  The  approach  was  to  apply  a  signal  level  well  above  the  minimum  signal  level  at  TOV  (by  about  50  dB)  so  that  signal  level  was  not  an 
 issue. 
 Details  on  the  test  methods  and  configurations  are  presented  in  Appendix  A. 


 Thresholds 
 For  both  types  of  threshold  measurements  (required  CNR  and  minimum  signal  at  TOV),  the  reported  value  is  the  level  measured  on  the  maximum  attenuation  step  (lowest  signal  level)  that  resulted  in  no 


 observed  errors  in  60  seconds  of  viewing  time.  The  threshold  level  at  which  the  60-  second  viewing  time  condition  was  met  was  nominally  somewhere  between  that  reported  level  and  the  next  higher  attenuation 
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 level  (next  lower  signal  level  step);  consequently,  this  approach  can  be  expected  to  overestimate  required  signal  levels  by  an  average  of  half  the  attenuator  step  size  of  0.1  dB.  One  could  therefore  justify 
 subtraction  of  0.05  dB  from  the  measured  signal  levels.  This  subtraction  was  not  performed,  in  part  to  compensate  for  the  fact  that  TOV  measurements  are  often  based  on  longer  observation  times  than  the  60 
 seconds  used  in  these  tests. 
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 CHAPTER  3  WHITE-  NOISE  THRESHOLD  MEASUREMENTS 
 (REQUIRED  CARRIER-  TO-  NOISE  RATIO) 
 White-  noise  threshold  refers  to  the  ratio  of  signal  (  carrier)  power  to  noise  power  within  the  6-  MHz  bandwidth  of  a  television  channel  when  both  an  unimpaired  signal  (no  multipath)  and  broadband 


 (  white)  Gaussian  noise  are  simultaneously  applied  to  the  antenna  terminal  of  a  DTV  receiver  and  the  signal  or  noise  power  is  adjusted  to  the  point  at  which  observable  errors  in  the  DTV  picture  just  become 
 invisible  i.  e.,  the  threshold  of  visibility  (TOV).  This  is  the  carrier-  to-  noise  ratio  (CNR)  required  to  produce  a  clean  DTV  picture.  The  definition  assumes  that  the  applied  noise  power  is  sufficiently 
 higher  than  any  noise  generated  internally  by  the  DTV  receiver  circuitry  so  as  to  make  the  internally  generated  noise  negligible. 


 At  CNR  levels  below  the  white-  noise  threshold,  picture  quality  rapidly  degrades  to  the  point  that,  only  about  one  dB  below  the  white-  noise  threshold,  the  picture  is  typically  unwatchable  or  nonexistent. 
 At  CNR  levels  above  the  white-  noise  threshold,  the  picture  is  essentially  free  of  defects  that  are  related  to  transmission  and  reception  of  the  signal. 
 White  noise  threshold  is  of  direct  interest  because  it  indicates  the  ability  of  a  digital  television  to  receive  and  process  a  DTV  signal  in  the  presence  of  high  ambient  noise  levels  assuming  that  the  signal  is  not 
 significantly  impaired  by  multipath  or  interference  and  that  the  ambient  noise  has  characteristics  similar  to  white  Gaussian  noise.  In  cases  where  the  ambient  environment  is  quiet,  white  noise  threshold  is  useful 
 in  understanding  the  reception  performance  of  a  DTV  receiver  in  the  presence  of  noise  that  is  internally  generated  within  the  input  circuits  of  the  receiver. 


 The  results  of  this  chapter  apply  only  to  signals  that  are  unimpaired  by  multipath.  In  the  presence  of  multipath,  a  higher  CNR  may  be  required  to  produce  a  clean  picture.  While  the  measurements  performed 
 for  this  report  do  not  address  such  an  increase,  the  topic  is  discussed  in  Chapter  7,  based  on  earlier  field  test  results. 


 MEASUREMENT  METHOD 
 White-  threshold  of  each  receiver  was  measured  by  simultaneously  injecting  into  the  antenna  port  of  the  receiver  both  an  unimpaired  (e.  g.,  no  multipath)  ATSC  signal  on  channel  30  and  white  noise  from  a  noise 


 generator.  A  nine-  way  splitter  feeding  equal-  length,  well-  shielded,  low-  loss  cables  allowed  the  same  combination  of  signal  plus  noise  to  be  applied  simultaneously  to  as  many  as  eight  DTV  receivers  and  a 
 vector  signal  analyzer  that  was  used  for  the  measurements.  As  a  consistency  check,  receiver  D3  was  included  in  each  group  of  eight  receivers  that  were  tested;  measurements  of  D3  were  consistent  within 
 0.1  dB. 
 Impedance-  matching  attenuator  pads  (50  ohms  to  75  ohms,  5.8  dB  power  attenuation)  at  each  TV  receiver  served  to  match  the  nominal  75-  ohm  impedance  of  the  receiver  antenna  ports  to  the  rest  of  the  50-  ohm 
 measurement  system  and,  through  the  attenuation  it  provided,  served  to  reduce  the  impact  of  any  deviations  from  that  nominal  TV  input  impedance.  At  the  vector  signal  analyzer,  a  6-  dB,  50-  ohm 
 attenuator  served  a  similar  function. 
 Because  the  small  differences  in  loss  between  the  various  splitter  outputs,  cables,  and  pads  can  be  expected  to  equally  affect  both  the  signal  and  the  noise,  the  measured  CNR  is  not  affected  by  such 
 differences. 
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 The  signal  source  for  these  tests  was  an  RF  player  (Sencore  RFP-  910)  playing  the  Hawaii_  ReferenceA  file  supplied  with  the  player.  The  file  consisted  of  a  25-  second  repeating  loop  of  motion  video  scenes 
 shot  at  several  outdoor  locations.  At  each  loop  restart,  most  DTV  receivers  exhibited  video  errors  related  to  re-  locking  to  the  signal;  consequently,  the  first  three  seconds  of  each  loop  were  not  included  in  the 
 observation  time.  (An  ATSC  signal  generator,  rather  than  the  RF  player,  had  been  intended  for  these  tests.  Use  of  the  generator  would  have  avoided  issues  with  loop  restart  time,  but  the  generator  was 
 abandoned  due  to  degraded  signal  quality.)  The  signal  was  amplified  before  splitting  it.  A  step  attenuator  following  the  amplifier  was  used  to  adjust  the  signal  level. 


 The  noise  source  was  a  noise  generator  (Noise/  Com  UFX-  7110)  band  limited  to  700  MHz,  well  above  the  frequency  of  TV  channel  30,  thus  leaving  the  spectrum  flat  across  the  bandwidth  of  the  selected  TV 
 channel.  The  injected  noise  power  was  set  nominally  to  -70  dBm  within  the  6-  MHz  bandwidth  of  channel  30  about  29  dB  above  the  internally  generated  noise  of  a  typical  DTV  receiver  by  using  a  step 
 attenuator  with  0.1-  dB  steps.  The  noise  power  measurement  (usually  within  0.05  dB  of  -70  dBm)  was  then  recorded.  The  actual  injected  noise  power  was  computed  by  subtracting  the  effect  of  instrument 
 noise,  which  was  about  26  dB  below  the  injected  noise  power. 
 Signal  level  was  increased  in  0.1-  dB  steps  until  the  TV  picture  could  be  viewed  for  60  seconds  without  observing  a  video  error  (excluding  loop  restart  periods,  as  noted  above).  A  measurement  was  then  made 
 of  the  combined  power  of  both  the  injected  signal  and  the  injected  noise,  and  the  signal  power  was  computed  by  subtracting  the  noise  power  (in  linear  power  units);  since  the  noise  power  at  the  threshold 
 was  typically  about  15  dB  below  the  signal,  the  net  signal  power  was  only  about  0.1  dB  below  the  measured  total  power. 


 Further  details  on  the  measurement  procedure  are  contained  in  Appendix  A. 
 FORMAT  OF  THE  BAR  GRAPH  DATA 
 The  measurement  results  are  presented  in  bar-  graph  form  in  Figure  3-  1.  That  format,  explained  here,  is  also  used  in  subsequent  chapters  to  present  other  results. 


 Each  bar  on  the  graph  represents  performance  of  one  DTV  receiver.  The  Better/  Worse  labels  on  the  vertical  axis  indicate  that,  for  the  plotted  parameter,  lower  values  represent  better  performance. 
 Each  receiver  is  designated  by  a  letter  and  a  numeral.  The  letters,  which  were  assigned  randomly,  represent  brand  names.  Thus,  receivers  A1,  A2,  and  A3  are  all  of  the  same  brand. 
 The  receivers  are  grouped  into  categories.  The  first  category  is  set-  top  boxes  (STBs).  The  remaining  categories  are  three  different  price  ranges  of  DTVs.  Within  each  group,  the  results  are  listed  in  order  of 
 the  randomly  assigned  brand  code  letters  rather  than  in  price  order.  This  approach  was  taken  so  that  individual  products  could  not  be  identified  based  on  price. 


 The  solid  blue  line  represents  the  median  result  across  all  tested  receivers.  The  dashed  blue  line  represents  the  median  result  within  each  category.  The  dashed  red  line  represents  the  mean  result  within 
 each  category.  A  wider  dashed  green  line  represents  the  value  of  the  planning  factor  assigned  to  the  measured  parameter  by  OET-  69. 


 RESULTS 
 The  results  of  the  white-  noise  threshold  measurements  are  shown  in  Figure  3-  1. 
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 Nominal  Performance  and  Variation  Among  Samples 
 Statistics  of  the  white-  noise  threshold  (required  CNR)  are  shown  in  Table  3-  1.  The  white  noise  threshold  of  the  median  receiver  measured  across  all  tested  receivers  is  15.3  dB.  This  is  only  0.1  dB  above 


 (worse  than)  the  corresponding  planning  factor  value  in  OET-  69.  (Because  the  CNR  was  determined  from  the  ratio  of  two  power  measurements  performed  on  the  same  amplitude  range  of  the  same  measuring 
 instrument,  its  value  is  not  affected  by  absolute  calibration  accuracy  of  the  instrument  and  is  therefore  expected  to  be  accurate  to  within  0.2  dB.  *  ) 


 Table  3-  1.  Statistics  of  White  Noise  Threshold 
 WHITE  NOISE  THRESHOLD 
 Median  across  all  receivers  (dBm)  15.3 
 Median  re  OET-  69  planning  factors  0.1  Deviations  of  receivers  from  median  (dB) 


 --  Best  performing  receiver  (dB)  -0.4  --  Worst  performing  receiver  (dB)  0.5 
 --  89th  percentile  receiver  (dB)  0.3  Standard  deviation  (dB)  0.2 
 Total  span  from  best  to  worst  receiver  (dB)  0.8   
 The  variations  among  receivers  were  quite  small.  The  standard  deviation  of  the  CNR  measurements  across  all  receivers  was  0.2  dB.  The  total  span  from  best  to  worst  performing  receiver  was  0.8  dB,  with 
 the  worst  measured  white  noise  threshold  being  0.5  dB  above  the  median  value. 


 Variation  with  Price  and  Type  Category 


 Magnitude  of  Observed  Variations  With  Product  Type  and  Price 
 The  observed  performance  variations  among  the  product  type  and  price  categories  were  also  small,  as  shown  in  Table  3-  2.  The  least  expensive  way  to  receive  a  DTV  broadcast  is  to  purchase  a  digital  set-  top 


 box  and  connect  it  to  an  existing  TV.  Median  performance  of  set-  top  boxes  was  only  0.  1  dB  worse  than  the  overall  median.  The  median  low-  cost  and  mid-  cost  DTVs  performed  at  the  overall  median,  and  the 
 median  high-  cost  DTV  performance  was  0.2  dB  better  than  the  overall  median. 


 *  The  vector  signal  analyzer  specification  sheet  states  that  relative  accuracy  in  RF  vector  mode  on  a  single  range  is 
 the  sum  of  frequency  response  and  amplitude  linearity.  If  we  ignore  the  frequency  response  term  because  the  measurements  are  made  over  the  same  frequency  range,  we  are  left  with  the  amplitude  linearity  term,  which  is 


 specified  as  <  0.  1  dB  for  signal  levels  between  0  dB  and  -30  dB  with  respect  to  full  scale  a  condition  that  was  met  by  both  the  signal  and  injected  noise  measurements.  To  this  we  add  errors  caused  by  the  0.1-  dB  attenuator 
 step  size. 
   Span  does  not  match  difference  between  worst  and  best  due  to  rounding  of  all  numbers  to  nearest  0.1  dB. 
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 Table  3-  2.  Product-  Type/  Price  Variations  of  White  Noise  Threshold 
 WHITE  NOISE  THRESHOLD 
 Median  of  Set-  Top  Boxes  re  Overall  Median  (dB)  0.1 
 Median  of  Low-  Price  DTVs  re  Overall  Median  (dB)  0.0 
 Median  of  Medium-  Price  DTVs  re  Overall  Median  (dB)  0.0 
 Median  of  High-  Price  DTVs  re  Overall  Median  (dB)  -0.2 


 Statistical  Significance  of  Observed  Variations  With  Product  Type  and  Price 
 Apparent  variations  in  performance  of  samples  with  price  can  be  caused  by  random  sampling  effects  even  when  there  is  no  underlying  performance/  price  dependence  in  the  overall  population;  hence,  some  means 


 is  necessary  to  determine  whether  an  apparent  dependence  observed  in  the  sample  is  statistically  significant. 


 In  the  case  of  measurements  of  the  required  CNR  for  the  tested  collection  of  DTV  receivers,  the  observed  variations  with  price  are  so  small  as  to  be  inconsequential;  consequently,  assessing  the  statistical  validity 
 of  those  variations  is  hardly  necessary.  Nonetheless,  an  analysis  is  included  here  for  completeness  and  to  provide  a  comparative  basis  for  more  significant  observed  variations  that  are  presented  in  subsequent 
 chapters. 
 As  seen  in  Table  3-  3,  the  Pearsons  correlation  coefficient  between  required  CNR  and  receiver  price  was  computed  as  -8.6  percent  when  all  receivers  were  included  and  +7.  0  percent  when  only  the  DTVs  (not 
 set-  top  boxes)  were  included.  A  negative  sign  indicates  that  the  required  CNR  appears  to  decrease  (i.  e.,  improve)  with  increasing  receiver  price,  while  a  positive  sign  indicates  that  the  required  CNR  increases 
 (i.  e.,  degrades)  with  increasing  price.  Determining  whether  any  observed  apparent  trend  is  real  or  is  an  artifact  of  the  small  sample  set  used  in  the  tests  requires  a  statistical  assessment. 


 Table  3-  3.  Correlation  Coefficient  of  White  Noise  Threshold  with  Price 
 Pearsons  Correlation  Coefficient  of  White  Noise  Threshold  with  Price 


 All  Tested  Receivers  -8.6% 
 DTVs  Only  (no  Set-  Top  Boxes)  +7.0% 


 The  usual  method  of  assessing  the  statistical  significance  of  given  value  of  the  Pearsons  correlation  coefficient  is  to  compare  the  magnitude  of  the  observed  correlation  to  values  in  a  table  of  critical  values 
 of  the  Pearsons  correlation  coefficient.  The  technique  is  used  to  determine  the  likelihood  that  a  correlation  as  high  as  that  which  was  observed  might  occur  randomly,  for  the  selected  sample,  if  there  is 
 no  actual  correlation  between  required  CNR  and  receiver  price  in  the  larger  population  of  all  DTV  receivers.  Such  a  lookup  table  specifies  values  as  a  function  of  the  number  of  degrees  of  freedom, 
 which  is  two  less  than  the  total  number  of  samples  assuming  that  the  samples  are  independent. 
 For  the  overall  sample  size  used  in  this  study  (28  samples,  26  degrees  of  freedom),  one  can  determine  from  such  a  table  that  the  magnitude  of  an  observed  correlation  coefficient  must  be  32  percent  or  higher 
 in  order  to  ensure  that  there  is  no  more  than  a  five  percent  probability  that  the  observed  correlation  could  result  by  random  sampling  effects  from  a  larger  population  that  has  no  such  correlation.  In  the  case  of  the 
 23  DTVs  (i.  e.,  excluding  the  set-  top  boxes),  the  magnitude  of  an  observed  correlation  would  have  to  be  35  percent  or  higher  to  meet  the  same  criterion.  (These  are  single-  sided  probabilities  i.  e.,  the 
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 probability  that  a  correlation  magnitude  will  exceed,  in  a  single  direction,  a  given  correlation  value.  For  example,  if  the  overall  population  has  no  correlation  with  price,  there  is  a  five  percent  probability  that  the 
 correlation  of  a  randomly  selected  sample  of  28  receivers  will  exceed  a  32  percent  magnitude  with  a  negative  correlation  indicating  decreasing  CNR  with  increasing  receiver  price.  There  is  also  a  five 
 percent  probability  of  exceeding  that  same  magnitude  with  a  positive  correlation  indicating  increasing  CNR  with  increasing  price.) 


 It  should  be  noted  that  these  statistical  calculations  are  dependent  upon  a  number  of  assumptions,  including  that  the  shape  of  the  probability  distribution  of  the  measured  parameter  is  normal  (Gaussian), 
 that  the  samples  were  randomly  selected,  and  that  the  samples  are  independent.  None  of  these  assumptions  is  strictly  true  for  the  case  at  hand.  Of  particular  concern  is  the  independence  assumption, 
 because  it  is  quite  likely  that  some  of  the  receiver  samples  share  critical  subsystems.  For  example,  a  given  tuner  or  demodulator  design  may  be  used  in  more  than  one  of  the  receivers.  The  effect  of  such  a 
 commonality  between  samples  would  be  to  decrease  the  effective  number  of  degrees  of  freedom  in  the  computed  Pearsons  correlation  coefficient.  Such  a  decrease  would  increase  the  magnitude  of  correlation 
 that  would  have  to  be  observed  to  have  a  given  confidence  level  in  the  result. 
 The  observed  correlations  of  -8.6  percent  and  +7.0  percent  in  the  white-  noise  threshold  measurements  are  so  small  as  to  provide  no  confidence  that  the  small  observed  variations  in  performance  with  price  reflect  a 
 real  price-  dependence  in  the  overall  population  of  DTV  receivers  currently  on  the  market. 


 Effect  of  TV  Channel 
 White  noise  threshold  (required  CNR)  is  expected  to  be  dependent  on  the  demodulator  function  of  a  DTV  receiver.  Since  this  function  occurs  after  the  tuner  heterodynes  the  incoming  RF  signal  from  the 


 frequency  band  of  the  TV  channel  to  an  intermediate  frequency  (IF),  one  would  expect  the  white  noise  threshold  to  be  essentially  independent  of  TV  channel  number.  Consequently,  testing  was  performed  on 
 only  one  channel  channel  30. 
 In  testing  minimum  signal  level  of  the  DTV  receivers,  as  reported  in  the  next  chapter,  there  was  a  large  variation  in  the  results  between  channels  for  some  TVs.  In  order  to  verify  that  the  variation  was  not 
 related  to  changes  in  white  noise  threshold,  the  white  noise  threshold  of  one  DTV  receiver  was  also  tested  on  channel  3.  The  selected  receiver  was  G2,  the  receiver  with  the  largest  variation  in  minimum  signal 
 level  across  the  channels  (a  13  dB  difference  between  channels  3  and  30).  For  this  receiver,  the  measured  white  noise  thresholds  on  channels  3  and  30  were  15.6  and  15.  5  dB,  respectively;  this  difference  is  within 
 measurement  error. 
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 14.8 
 15.0 
 15.2 
 15.4 
 15.6 
 15.8 
 16.0 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 DTV  Receiver 


 White 
 Noise 
 Threshold 


 [Required 
 CNR] 
 (dB)  SNR  Overall  Median 
 Group  Median  Group  Mean 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs  $2001  -  $4200 


 Better 


 Worse 


 Figure  3-  1.  Measured  White  Noise  Threshold  of  Receivers 
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 CHAPTER  4  MINIMUM  INPUT  SIGNAL  MEASUREMENTS 
 Minimum  input  signal  at  the  threshold  of  visibility  (TOV)  is  the  signal  (  carrier)  power  at  the  antenna  terminal  of  a  DTV  receiver  when  the  signal  level  is  adjusted  to  the  point  at  which  observable  errors  in  the 
 DTV  picture  just  become  invisible.  It  is  a  direct  measure  of  sensitivity  of  a  DTV  receiver  to  weak  signals  in  the  absence  of  significant  externally  generated  noise  or  interference  assuming  that  the  input  signal  is 
 not  significantly  impaired  by  multipath.  At  input  levels  below  this  threshold  level,  picture  quality  rapidly  degrades  to  the  point  that,  only  about  one  dB  below  the  white-  noise  threshold,  the  picture  is  typically 
 unwatchable  or  nonexistent.  At  input  levels  above  the  threshold,  the  TV  picture  is  essentially  free  of  defects  that  are  related  to  transmission  and  reception  of  the  signal. 


 The  results  of  this  chapter  apply  only  to  signals  that  are  unimpaired  by  multipath  or  interference.  In  the  presence  of  multipath,  a  higher  signal  level  may  be  required  to  produce  a  clean  picture.  While  the 
 measurements  performed  for  this  report  do  not  address  such  an  increase,  the  topic  is  discussed  in  Chapter  7,  based  on  earlier  field  test  results. 


 MEASUREMENT  METHOD 
 Because  minimum  input  signal  at  TOV  is  an  absolute  measurement  rather  than  a  ratio,  the  splitter  was  not  used  for  these  tests.  The  receivers  were  tested  sequentially  in  groups  of  about  eight  with  receiver  D3 


 included  in  each  group,  as  a  consistency  check;  measurements  of  D3  were  consistent  within  0.  3  dB.  The  results  are  subject  to  the  absolute  measurement  accuracy  of  the  vector  signal  analyzer,  which  is  specified 
 as  1.  5  dB  maximum  and  0.  5  dB  typical  on  the  amplitude  range  that  was  used  for  the  measurements;  *  additional  errors  due  to  adjustment  for  attenuation  of  impedance-  matching  pad  as  described  below  are 
 expected  to  be  negligible  compared  to  the  VSA  tolerance. 
 The  tests  were  performed  on  three  TV  channels  3,  10,  and  30  in  order  to  evaluate  performance  in  the  low  VHF,  high  VHF,  and  UHF  bands,  respectively.  The  selection  of  those  specific  channels  was  based 
 on  avoiding  local  broadcast  channels  and  selection  of  a  relatively  central  channel  within  each  band. 
 The  signal  source  for  these  tests  was  an  RF  player  (Sencore  RFP-  910)  playing  the  Hawaii_  ReferenceA  file  supplied  with  the  player.  The  file  consisted  of  a  25-  second  repeating  loop  of  motion  video  scenes 
 shot  at  several  outdoor  locations.  At  each  loop  restart,  many  DTV  receivers  exhibited  video  errors  related  to  re-  locking  to  the  signal;  consequently,  the  first  three  seconds  of  each  loop  were  not  included  in  the 
 observation  time.  A  step  attenuator  was  used  to  adjust  the  signal  level.  The  signal  was  applied  to  a  single  DTV  receiver  through  a  low-  loss  50-  ohm  cable  followed  by  a  10-  dB  attenuator  pad  and  an  impedance-matching 
 attenuator  pad  having  5.8  dB  power  attenuation.  The  latter  served  to  match  the  nominal  75-  ohm  impedance  of  the  receiver  antenna  port  to  the  rest  of  the  50-  ohm  measurement  system.  Both  pads  served 


 *  As  an  additional  check  on  equipment  performance,  measurements  of  injected  broadband  signal  level  and  of 
 injected  broadband  noise  level  at  levels  typical  of  those  used  for  white-  noise  threshold  testing  (-  70  dBm  for  noise  and  -55  dBm  for  signal  both  measured  across  the  6-  MHz  bandwidth  of  TV  channel  30)  were  performed 


 using  two  instruments,  the  vector  signal  analyzer  and  a  spectrum  analyzer  (Agilent  E7405A).  The  spectrum  analyzer  measurements  were  made  with  the  internal  preamp  on  and  the  internal  attenuation  set  to  0  dB.  The 
 spectrum  analyzer  overall  amplitude  accuracy  is  specified  as  (  0.  54  dB  +  absolute  frequency  response)  with  the  absolute  frequency  response  being  specified  as  0.  5  dB  over  the  frequency  range  of  interest.  For  both  signal  and 
 noise,  the  spectrum  analyzer  measurements  were  0.  1  dB  higher  than  the  vector  signal  analyzer  measurements  suggesting  that  both  instruments  (which  were  calibrated  no  more  than  two  months  before  the  measurements 
 reported  in  this  chapter)  were  likely  performing  well  within  the  specified  tolerances.  (Note  that  self  calibrations  were  also  performed  on  both  instruments  before  each  set  of  measurements.) 
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 to  minimize  reflections  that  might  be  caused  by  any  deviation  of  receiver  input  impedance  from  the  nominal. 
 Signal  level  was  increased  in  0.1-  dB  steps  until  the  TV  picture  could  be  viewed  for  60  seconds  without  observing  a  video  error  (excluding  loop  restart  periods,  as  noted  above).  The  low-  loss  cable  and  10-  dB 
 pad  were  then  connected  to  a  vector  signal  analyzer  on  its  most  sensitive  amplitude  range  (-  50  dBm)  to  measure  the  power  of  the  applied  signal.  The  10-  dB  pad  served  to  minimize  reflections  that  would  be 
 caused  by  any  deviation  of  the  vector  signal  analyzer  input  impedance  from  50  ohms.  A  separate  measurement  of  instrument  noise  (typically  about  19  dB  below  the  measured  signal  level)  was 
 subtracted  in  linear  power  units  from  the  measured  power  level  to  remove  the  very  minor  effects  of  vector  signal  analyzer  self  noise  from  the  measurement.  The  attenuation  of  the  impedance  matching  pad, 
 which  was  connected  to  the  TV  input  but  not  to  the  vector  signal  analyzer,  was  then  subtracted  (in  dB)  from  the  result  to  determine  the  signal  level  that  had  been  applied  to  the  DTV  receiver  antenna  port.  The 
 presence  of  that  pad  at  the  TV  input  but  not  at  the  spectrum  analyzer  input  served  a  dual  purpose  matching  the  respective  input  impedances  of  the  two  devices  and  providing  a  5.8  dB  signal  advantage  to 
 the  vector  analyzer  to  minimize  the  impact  of  the  vector  signal  analyzer  self  noise. 
 Further  details  on  the  measurement  procedure  are  contained  in  Appendix  A. 


 RESULTS 
 The  results  of  the  minimum  signal  level  measurements  for  the  three  tested  channels  are  shown  in  Figure  4-  1.  Individual  results  for  TV  channels  3,  10,  and  30  are  shown  in  Figures  4-  2,  4-  3,  and  4-  4, 


 respectively.  The  general  format  of  the  plots  is  as  described  in  Chapter  3  in  the  section  titled,  Format  of  the  Bar  Graph  Data,  except  that,  in  the  case  of  Figure  4-  1,  there  are  three  bars  per  DTV  receiver 
 representing  the  three  channels  tested.  Also,  note  the  differences  in  vertical  scales  among  the  four  graphs. 


 Nominal  Performance  and  Variation  Among  Samples 
 Table  4-  1  shows  the  statistical  properties  of  the  measurements  of  minimum  signal  level  at  TOV. 


 Table  4-  1.  Statistics  of  Minimum  Signal  Level  at  TOV 
 MINIMUM  SIGNAL  LEVEL  AT  TOV  Chan  3  Chan  10  Chan  30 
 Median  across  all  receivers  (dBm)  -82.2  -83.2  -83.9 
 Median  re  OET-  69  planning  factors  -1.2  -2.2  0.1  Deviations  of  receivers  from  median  (dB) 


 --  Best  performing  receiver  (dB)  -2.5  -1.7  -1.4  --  Worst  performing  receiver  (dB)  12.5  4.  3  2.5 
 --  89th  percentile  receiver  (dB)  5.1  3.  1  1.3  Standard  deviation  (dB)  3.7  1.  6  0.9 
 Total  span  from  worst  to  best  receiver  (dB)  15.0  6.  0  3.9 
 The  median  minimum  signal  level  at  TOV  across  all  measured  receivers  was  found  to  decrease  slightly  with  increasing  channel  number  with  channel  3  requiring  a  1.7-  dB  higher  signal  than  channel  30.  The 
 measured  median  values  match  within  1  dB  the  -83  dBm  minimum  performance  standard  recommended  by  the  ATSC.  * 


 *  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced  Television 
 Systems  Committee,  17  June  2004,  p.  11. 
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 The  median  required  signal  levels  were  slightly  better  by  1.2  dB  and  2.2  dB,  respectively  than  that  predicted  for  the  VHF-  low  and  VHF-  high  bands  using  the  OET-  69  planning  factors  (-  81.0  dBm)  and 
 closely  matched  the  predictions  for  channel  30  (-  84.0  dBm).  *  On  channel  3,  only  21  percent  of  the  tested  receivers  performed  more  poorly  in  minimum  signal  level  than  the  performance  modeled  in  OET-  69  by 
 an  amount  exceeding  1-  dB  the  approximate  tolerance  of  the  measurements.    On  channels  10  and  30,  the  numbers  are  11  percent  and  18  percent,  respectively. 


 The  variation  among  receivers  was  large  on  channel  3  with  a  3.7-  dB  standard  deviation.  The  two  receivers  exhibiting  poorest  performance  performed  at  levels  10.6  and  12.5  dB  worse  than  the  median. 
 Those  two  receivers  both  the  same  brand  are  responsible  for  much  of  the  observed  variability;  omitting  them  from  the  calculations  reduces  the  standard  deviation  to  2.3  dB.  The  third  worst  performer 
 was  6.7  dB  above  the  median.  89  percent  of  the  receivers  (all  but  three)  were  within  5.1  dB  of  the  median. 


 Variations  were  relatively  small  on  channels  10  and  30.  Standard  deviation  across  all  receivers  was  1.6  dB  on  channel  10  and  0.  9  dB  on  channel  30.  The  worst  performers  differed  from  the  median  by  4.3 
 and  2.5  dB,  respectively,  on  channels  10  and  30,  and  89  percent  of  the  receivers  (all  but  three)  were  no  more  than  3.1  dB  above  (worse  than)  the  median  on  channel  10  and  no  more  than  1.3  dB  above  (worse 
 than)  the  median  on  channel  30. 


 Variations  With  TV  Channel  For  One  Sample 
 At  least  two  TVs  exhibited  a  much  larger  than  expected  variation  in  reception  performance  as  measured  by  minimum  signal  level  at  TOV  between  the  three  tested  TV  channels.  In  order  to  further  characterize 


 this  variation,  the  receiver  exhibiting  the  largest  variation  between  channels  (receiver  G2)  was  further  tested  to  determine  minimum  signal  at  TOV  for  each  of  the  12  VHF  channels  and  for  three  UHF 
 channels.  The  results,  shown  in  Figure  4-  5,  indicate  that  the  receiver  exhibits  poor  sensitivity  throughout  the  low-  VHF  band  (channels  2  through  6),  but  good  sensitivity  throughout  the  high-  VHF  band  (channels 
 7  through  13)  and  the  UHF  band.  On  average,  the  high-  VHF  and  UHF  performance  is  13  dB  better  than  the  low-  VHF  performance.  The  reason  for  this  performance  difference  is  not  known. 


 The  apparently  abrupt  change  in  sensitivity  occurring  between  channels  6  and  7  is  easier  to  understand  if  the  data  is  plotted  as  a  function  of  frequency,  as  in  Figure  4-  6.  It  can  be  seen  that  there  is  a  large  gap  in 
 frequency  between  TV  channels  6  and  7,  and  that  the  increase  in  minimum  signal  at  TOV  that  occurs  in  moving  from  the  high-  VHF  band  (channels  7-  13)  to  the  low-  VHF  band  (channels  2-  6)  appears  to  actually 
 begin,  to  a  small  degree,  in  the  lower  portion  of  the  high-  VHF  band.  (Note  that  the  measured  data  is  indicated  by  square  symbols  and  measured  points  are  connected  by  straight  lines.) 


 Variation  with  Price  and  Type  Category 
 Magnitude  of  Observed  Variations  With  Product  Type  and  Price 
 As  can  be  seen  in  Table  4-  2,  the  observed  variations  in  minimum  signal  level  at  TOV  with  product  type  and  price  categories  were  very  small  for  channels  10  and  30  (category  medians  differing  from  overall 


 median  by  less  than  1  dB)  and  were  somewhat  larger  for  channel  3.  On  channel  3,  median  performance  of  set-  top  boxes  was  2.0  dB  worse  than  the  overall  median  of  all  receivers  and  the  best  median 


 *  See  note  for  Table  1-  1. 
   Absolute  measurement  accuracy  of  the  vector  signal  analyzer  on  the  amplitude  range  that  was  used  for  the 
 measurements  was  as  1.  5  dB  maximum  and  0.  5  dB  typical. 
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 performance  was  achieved  by  the  low-  price  DTV  category,  which  slightly  outperformed  the  medium  and  high-  priced  categories.  Most  of  the  differences  in  median  values  between  categories  are  so  small  as  to  be 
 considered  insignificant,  and  even  the  largest  differences  would  influence  reception  performance  only  in  locations  where  the  signal  margin  is  very  small. 


 Table  4-  2.  Product-  Type/  Price  Variations  of  Minimum  Signal  at  TOV 
 MINIMUM  SIGNAL  LEVEL  AT  TOV  Chan  3  Chan  10  Chan  30 
 Median  of  Set-  Top  Boxes  re  Overall  Median  (dB)  2.0  0.5  0.7 
 Median  of  Low-  Price  DTVs  re  Overall  Median  (dB)  -1.1  -0.2  -0.2 
 Median  of  Medium-  Price  DTVs  re  Overall  Median  (dB)  0.0  0.5  0.0 
 Median  of  High-  Price  DTVs  re  Overall  Median  (dB)  -0.7  -0.3  0.0 


 Statistical  Significance  of  Observed  Variations  With  Product  Type  and  Price 
 Table  4-  3  shows  the  Pearsons  correlation  coefficient  between  the  minimum  signal  at  TOV  and  the  price  of  each  DTV  receiver.  Random  sampling  effects  can  lead  to  apparent  correlations  in  a  given  collection  of 


 DTV  receivers  even  if  the  overall  DTV  population  of  receivers  on  the  market  exhibits  no  such  correlation;  consequently,  a  statistical  assessment  must  be  performed  in  order  to  judge  whether  the  observed 
 correlation  reflects  an  actual  correlation  in  overall  population  or  is  simply  an  artifact  of  sampling. 


 Table  4-  3.  Correlation  Coefficient  of  Minimum  Signal  at  TOV  with  Price 
 Pearsons  Correlation  Coefficient  of  Minimum  Signal  at  TOV  with  Price  Chan  3  Chan  10  Chan  30 


 All  Tested  Receivers  -14.3%  -4.9%  +3.9% 
 DTVs  Only  (no  Set-  Top  Boxes)  -0.3%  +0.4%  +12.3% 


 Chapter  3  explains  the  methods  and  pitfalls  of  such  a  statistical  assessment.  Using  typical  assumptions,  one  would  conclude  that  an  observed  correlation  coefficient  with  a  magnitude  of  32  percent  or  higher  is 
 unlikely  to  occur  (less  than  five  percent  probability)  in  a  sample  size  of  28  (the  total  number  of  receivers  tested  for  this  report)  if  there  is  no  correlation  in  the  overall  population.  Similarly,  with  a  sample  size  of 
 23  (the  number  of  DTVs  excluding  set-  top  boxes  tested  for  this  report),  a  correlation  coefficient  magnitude  of  35  percent  or  higher  is  unlikely  to  occur  if  there  is  no  correlation  in  the  overall  population. 
 Thus,  we  would  conclude  that  an  observed  correlation  is  statistically  significant  only  if  its  magnitude  exceeds  the  appropriate  one  of  these  thresholds.  * 


 None  of  the  price/  performance  correlations  found  here  come  even  close  to  the  threshold  for  statistical  significance.  Thus,  the  measurements  of  minimum  signal  at  TOV  show  no  statistically  significant 
 correlation  of  performance  with  price. 
 *  As  is  explained  in  Chapter  3,  the  statistical  assessment  performed  above  is  dependent  upon  a  number  of 
 assumptions  that  are  not  strictly  true  for  the  case  at  hand.  Arguably,  the  most  questionable  of  these  is  the  assumption  that  the  performance  of  the  each  receiver  sample  is  independent  of  the  others.  It  is  quite  likely  that 


 some  of  the  receiver  samples  share  critical  subsystems,  which  would  violate  the  independence  assumption.  For  example  a  given  tuner  or  demodulator  design  may  be  used  in  more  than  one  of  the  receivers.  The  effect  of  such  a 
 commonality  between  samples  would  be  to  decrease  the  effective  number  of  degrees  of  freedom  in  the  computed  Pearsons  correlation  coefficient.  Such  a  decrease  would  increase  the  magnitude  of  correlation  that  would  have  to 
 be  observed  to  have  a  given  confidence  level  in  the  result.  Taking  this  effect  into  account  would  further  diminish  any  statistical  significance  of  the  results. 
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 -85 
 -80 
 -75 
 -70 
 -65 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dBm) 


 Chan  3 
 Chan  10 
 Chan  30 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  4-  1.  Measured  Minimum  Signal  Level  at  TOV  on  Three  Channels 
 -86 
 -85 
 -84 
 -83 
 -82 
 -81 
 -80 
 -79 
 -78 
 -77 
 -76 
 -75 
 -74 
 -73 
 -72 
 -71 
 -70 
 -69 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dBm) 


 Measured 
 Group  Median 
 Overall  Median 
 Group  Mean 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  4-  2.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  3  (Low  VHF) 
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 -86 
 -85 
 -84 
 -83 
 -82 
 -81 
 -80 
 -79 
 -78 
 -77 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dBm) 


 Measured 
 Group  Median 
 Overall  Median 
 Group  Mean 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  4-  3.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  10  (High  VHF) 
 -86 
 -85 
 -84 
 -83 
 -82 
 -81 
 -80 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dBm) 


 Measured 
 Group  Median 
 Overall  Median 
 Group  Mean 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  4-  4.  Measured  Minimum  Signal  Level  at  TOV  on  Channel  30  (UHF) 
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 -84 
 -82 
 -80 
 -78 
 -76 
 -74 
 -72 
 -70 
 -68 
 -66 


 2  3  4  5  6  7  8  9  10  11  12  13  14  30  51 
 TV  Channel  Number 


 Minimum 
 Signal 
 at 
 TOV 


 (dBm) 


 VHF-  LOW  TV  CHANNELS  VHF-  HIGH  TV  CHANNELS  UHF  TV  CHANNELS 


 Figure  4-  5.  Measured  Minimum  Signal  Level  at  TOV  Versus  Channel  for  Receiver  G2 


 -84 
 -82 
 -80 
 -78 
 -76 
 -74 
 -72 
 -70 
 -68 
 -66 


 50  100  150  200  250  300  350  400  450  500  550  600  650  700 
 Center  Frequency  of  TV  Channel  (MHz) 


 Minimum 
 Signal 
 at 
 TOV 


 (dBm) 


 VHF-  LOW 
 TV  BAND 
 VHF-  HIGH 
 TV  BAND 
 UHF  TV 
 BAND 


 Figure  4-  6.  Measured  Minimum  Signal  Level  at  TOV  Versus  Frequency  for  Receiver  G2 
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 CHAPTER  5  INFERRED  NOISE  FIGURE 
 The  minimum  signal  level  at  TOV,  presented  in  Chapter  4,  can  be  viewed  as  the  combined  effect  of  two  properties  of  the  DTV  receiver:  the  internal  noise  created  by  the  receivers  input  circuitry  and  the  CNR 
 required  to  produce  a  clean  picture.  Separating  the  measurement  into  those  two  basic  terms  provides  a  better  understanding  of  the  differences  in  performance  between  DTV  receivers.  It  should  be  noted  that 
 this  breakout  is  strictly  valid  only  when  reception  sensitivity  is  limited  by  the  receivers  amplifier  noise,  which  we  anticipate  to  be  true  for  most  receivers;  however,  if  other  factors  limit  reception  sensitivity,  the 
 inferred  receiver  noise  calculations  in  this  chapter  reflect  those  other  performance  limitations  rather  than  actual  receiver  noise.  * 


 The  internal  noise  created  by  a  receiver  is  often  expressed  in  terms  of  noise  figure.  The  noise  figure  of  a  receiver  is  the  effective  amount  of  noise  created  by  the  input  circuitry  of  the  receiver,  measured  relative  to 
 a  physical  limit  on  noise  known  as  thermal  noise  and  referenced  to  the  input  of  the  receiver.  While  noise  figure  cannot  be  directly  measured  externally,  the  effective  noise  figure  can  be  inferred  from  the  required 
 CNR  measurements  of  Chapter  3  in  conjunction  with  the  minimum  signal  level  at  TOV,  as  measured  in  Chapter  4. 


 Figure  5-  1(  a)  illustrates  measurement  of  required  CNR  (i.  e.,  white  noise  threshold).  The  vertical  line  represents  a  range  of  signal  and  noise  amplitudes  that  could  be  applied  to  the  antenna  terminal  of  a  TV 
 receiver.  With  external  white  noise  added  at  a  level  well  above  the  internal  noise  of  the  receiver,  signal  levels  in  the  lower,  red  portion  of  the  line  will  result  in  no  TV  picture.  Signals  in  the  yellow  range  will 
 produce  a  picture  degraded  by  demodulation  errors.  Signals  in  the  green  range,  with  signal  level  exceeding  the  noise  level  by  an  amount  greater  than  the  required  CNR,  will  produce  a  picture  free  of 
 reception-  related  defects.  (The  carrier-  to-  noise  ratio  (CNR),  becomes  a  difference  rather  than  a  ratio,  because  of  the  logarithmic  scaling  implied  by  measurements  in  decibels.) 


 Figure  5-  1(  b)  illustrates  measurement  of  minimum  signal  at  TOV,  the  minimum  signal  level  required  to  achieve  a  clear  picture  absent  any  external  noise.  Assuming  that  the  TV  reception  is  limited  by  the 
 receivers  broadband  internal  noise,  this  minimum  signal  level  can  be  viewed  as  the  sum  (in  dB)  of  two  parameters  the  internally  generated  noise  level  of  the  DTV  receiver  and  the  amount  by  which  the  signal 
 must  exceed  that  noise  level,  i.  e.,  the  required  CNR.  The  noise  level  of  the  receiver  can  be  expressed  as  the  sum  (in  dB)  of  the  noise  figure  of  the  receiver  and  the  thermal  noise  at  some  reference  temperature. 
 Thus,  we  have 
 Minimum  Signal  at  TOV  (dBm)  =  Thermal  Noise  (dBm)  +  Noise  Figure  (dB)  +  Required  CNR  (dB) 
 Thermal  noise  is  a  function  only  of  reference  temperature  and  measurement  bandwidth  and  is  given  by 
 Thermal  Noise  (dBm)  =  10  log(  k  T  B)  +  10  log(  1000  mW/  W) 


 *  Various  receiver  design  anomalies  could  result  in  reception  sensitivity  being  limited  by  factors  other  than 
 receiver  noise  (noise  figure).  For  example,  if  the  AGC  (automatic  gain  control)  does  not  allow  sufficient  RF  and  IF  gain  to  amplify  a  weak  signal  to  the  level  necessary  for  demodulation,  reception  performance  will  be  limited  by 


 gain  rather  than  by  amplifier  noise.  Similarly,  receiver  performance  could  also  be  limited  by  local  oscillator  phase  noise  or  by  leakage  into  the  tuner  of  internally-  generated  interference  sources  such  as  impulse  noise  from  digital 
 circuits  or  narrowband  (tonal)  interference. 
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 where  k  =  Boltzmanns  constant  =  1.38065  x  10  -23  joules/  K 
 T  =  reference  temperature  in  degrees  Kelvin  (290  K  for  this  report)  *  B  =  the  measurement  bandwidth  =  6,000,000  Hz  for  a  television  channel 
 10  log(  1000  mW/  W)  provides  the  conversion  from  dBWatts  to  dBmilliwatts 
 Using  the  above  values,  thermal  noise  =  -106.2  dBm. 
 If  the  noise  generated  internally  by  the  DTV  receiver  is  similar  to  white  Gaussian  noise,  then  the  required  CNR  in  Figure  5-  1(  a)  is  the  same  as  that  in  Figure  5-  1(  b);  consequently,  noise  figure  of  the  receiver  can 
 be  computed  as 
 Noise  Figure  (dB)  =  Minimum  Signal  at  TOV  (dBm)    Required  CNR  (dB)    Thermal  Noise  (dBm) 


 RESULTS 
 The  noise  figures  for  all  tested  receivers  on  the  three  tested  channels  have  been  computed  as  above  and  are  shown  in  Figure  5-  2.  Individual  results  for  TV  channels  3,  10,  and  30  are  shown  in  Figures  5-  3,  5-  4, 


 and  5-  5,  respectively.  The  general  format  of  the  plots  is  as  described  in  Chapter  3  in  the  section  titled,  Format  of  the  Bar  Graph  Data,  except  that,  in  the  case  of  Figure  5-  2,  there  are  three  bars  per  DTV 
 receiver  representing  the  three  channels  tested.  The  reader  should  note  the  differences  in  vertical  scales  among  the  four  graphs. 


 Note  that  in  performing  the  noise  figure  calculation,  the  required  CNR  is  assumed  to  be  constant  across  the  TV  channels  for  the  reasons  discussed  in  the  Effect  of  TV  Channel  section  of  Chapter  3.  Thus,  the 
 CNR  measurements  on  channel  30  are  applied  to  channels  3  and  10,  as  well. 


 Nominal  Noise  Figure  and  Variation  Among  Samples 
 Table  5-  1  shows  the  statistical  properties  of  the  noise  figure  across  all  tested  receivers. 


 Table  5-  1.  Statistics  of  Receiver  Noise  Figure 


 NOISE  FIGURE  Chan  3  Chan  10  Chan  30  Median  across  all  receivers  (dB)  8.8  7.6  6.9 
 Median  re  OET-  69  planning  factors  -1.2  -2.4  -0.1  Deviations  of  receivers  from  median 
 --  Best  performing  receiver  (dB)  -2.5  -1.3  -1.3  --  Worst  performing  receiver  (dB)  12.2  4.5  2.6 
 --  89  th  percentile  receiver  (dB)  4.5  3.3  1.2  Standard  deviation  (dB)  3.6  1.6  0.9 
 Total  span  from  worst  to  best  receiver  (dB)  14.7  5.7  3.9 
 The  median  noise  figure  across  all  measured  receivers  was  found  to  decrease  with  channel  with  the  noise  on  channel  30  being  1.9  dB  lower  than  that  on  channel  3.  The  median  noise  figures  were  1.2  to 
 2.4  dB  better  than  those  shown  in  the  OET-  69  planning  factors  for  the  VHF  bands  (10  dB)  and  essentially  matched  the  planning  factor  for  the  UHF  band  (7  dB). 


 *  The  reference  temperature  is  generally  taken  as  the  antenna  temperature.  290  K  =  17  C  =  62  F  results  in  a 
 thermal  noise  level  matching  the  -106.  2  dB  value  used  in  OET-  69. 
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 On  channel  3,  only  21  percent  of  the  tested  receivers  performed  more  poorly  in  noise  figure  than  the  value  modeled  in  OET-  69  by  an  amount  exceeding  1-  dB  the  approximate  tolerance  of  the  measurements.  *  On 
 channels  10  and  30,  the  numbers  are  7  percent  and  18  percent,  respectively. 
 The  variations  among  receivers  were  large  on  channel  3  with  a  3.6  dB  standard  deviation  and  two  receivers  performing  at  levels  10.3  and  12.2  dB  worse  than  the  median.  More  attention  to  tuner  design 
 for  those  two  receivers  might  significantly  improve  performance  in  weak  signal  conditions.  89  percent  of  the  receivers  (all  but  three)  were  no  more  than  4.5  dB  above  (worse  than)  the  median  noise  figure. 


 Variations  were  relatively  small  on  channels  10  and  30.  Standard  deviation  across  all  receivers  was  1.6  dB  on  channel  10  and  0.  9  dB  on  channel  30.  The  worst  performers  differed  from  the  median  by  4.5 
 and  2.6  dB,  respectively,  on  channels  10  and  30,  and  89  percent  of  the  receivers  (all  but  three)  were  no  more  than  3.3  dB  above  (worse  than)  the  median  noise  figure  on  channel  10  and  no  more  than  1.2  dB 
 above  the  median  noise  figure  on  channel  30. 


 Variation  With  Product  Type  and  Price 


 Magnitude  of  Observed  Variations  With  Product  Type  and  Price 
 As  can  be  seen  in  Table  5-  2,  the  observed  variations  in  receiver  noise  figure  with  product  type  and  price  categories  were  very  small  (category  medians  differing  from  overall  median  by  less  than  1  dB)  for 


 channels  10  and  30  and  were  somewhat  larger  for  channel  3.  On  channel  3,  median  noise  figure  of  set-top  boxes  was  1.7  dB  worse  than  the  overall  median  of  all  receivers.  The  best  median  noise  figure 
 1.4  dB  better  than  the  overall  median  occurred  in  the  low-  price  DTV  category.  Such  differences  are  likely  to  influence  performance  only  in  locations  where  the  signal  margin  is  very  small. 


 Table  5-  2.  Product-  Type/  Price  Variations  of  Receiver  Noise  Figure 
 NOISE  FIGURE  Chan  3  Chan  10  Chan  30 
 Median  of  Set-  Top  Boxes  re  Overall  Median  (dB)  1.7  0.1  0.6 
 Median  of  Low-  Price  DTVs  re  Overall  Median  (dB)  -1.4  -0.1  0.0 
 Median  of  Medium-  Price  DTVs  re  Overall  Median  (dB)  0.0  0.4  -0.1 
 Median  of  High-  Price  DTVs  re  Overall  Median  (dB)  -0.8  -0.3  0.0 


 Statistical  Significance  of  Observed  Variations  With  Product  Type  and  Price 
 Table  5-  3  shows  the  Pearsons  correlation  coefficient  between  the  noise  figure  and  the  price  of  each  DTV  receiver.  Given  the  similarity  of  results  with  those  for  minimum  signal  at  TOV,  the  reader  is  referred  to 


 Chapter  4  for  a  discussion  of  the  interpretation  of  these  results.  The  bottom  line  is  that  there  is  no  statistically  significant  correlation  of  noise  figure  with  price  of  the  receivers.. 


 *  Absolute  measurement  accuracy  of  the  vector  signal  analyzer  on  the  amplitude  range  that  was  used  for  the 
 measurements  was  as  1.  5  dB  maximum  and  0.  5  dB  typical. 
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 Table  5-  3.  Correlation  Coefficient  of  Receiver  Noise  Figure  with  Price 
 Pearsons  Correlation  Coefficient  of  Noise  Figure  with  Price  Chan  3  Chan  10  Chan  30 


 All  Tested  Receivers  -14%  -4%  +6% 
 DTVs  Only  (no  Set-  Top  Boxes)  -1%  -1%  +11% 


 Relative  Variations  in  Noise  Figure  and  Required  CNR 
 Figure  5-  6  shows  the  required  CNR  for  each  receiver  as  a  function  of  noise  figure  on  each  of  the  three  tested  channels.  Contour  lines  can  be  used  to  read  the  combined  effect  of  the  two  parameters  on 


 minimum  signal  at  TOV.  It  is  clear  from  the  plot  that  most  of  the  variation  in  receive  sensitivity  (i.  e.,  minimum  signal  level  at  TOV)  of  the  DTV  receivers  is  due  to  variations  in  receiver  noise  figures  rather 
 than  variations  in  the  CNR  required  by  the  demodulator.  In  fact,  based  on  standard  deviations  of  the  parameters,  variability  in  noise  figure  among  the  receivers  is  4.2  times  as  high  as  the  variability  in 
 required  CNR  on  channel  30,  where  the  noise  figure  variations  are  smallest.  On  channels  10  and  3,  respectively,  the  noise  figure  shows  7  and  16  times  the  variability  of  required  CNR. 
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 Added  White 
 Noise  [+  Receiver 
 Noise] 


 Apply  Clean  Signal  +  Noise 


 Required  CNR 
 Perfect  Reception 


 No  Picture 
 Picture  w/  errors 


 Added  White 
 Noise  [+  Receiver 
 Noise] 


 Apply  Clean  Signal  +  Noise 


 Required  CNR 
 Perfect  Reception 


 No  Picture 
 Picture  w/  errors 


 Required  CNR 
 Noise  Figure 
 Thermal  Noise  (-  106.  2  dBm) 


 Receiver  Noise 


 Minimum  Signal  at  TOV 


 Apply  Clean  Signal 


 Perfect  Reception 
 No 
 Picture 


 Picture  w/  errors  Required 
 CNR 


 Noise  Figure 
 Thermal  Noise  (-  106.  2  dBm) 


 Receiver  Noise 


 Minimum  Signal  at  TOV 


 Apply  Clean  Signal 


 Perfect  Reception 
 No 
 Picture 


 Picture  w/  errors 


 (a)  Required  CNR  (b)  Minimum  Signal  at  TOV 
 Figure  5-  1.  Relationship  between  Minimum  Signal  at  TOV  and  Required  CNR 


 5 
 6 
 7 
 8 
 9 
 10 
 11 
 12 
 13 
 14 
 15 
 16 
 17 
 18 
 19 
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 21 
 22 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Noise 
 Figure 


 (dB) 


 Chan  3 
 Chan  10 
 Chan  30 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  5-  2.  Noise  Figure  on  Three  Channels 
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 5-  6 
 5 
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 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Receiver 
 Noise 
 Figure 


 (dB) 


 Measured 
 Group  Median 
 Overall  Median 
 Group  Mean 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs  $2001  -  $4200 


 Better 
 Worse 


 Figure  5-  3.  Noise  Figure  on  Channel  3  (Low  VHF) 
 5 
 6 
 7 
 8 
 9 
 10 
 11 
 12 
 13 
 14 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Receiver 
 Noise 
 Figure 


 (dB) 


 Measurement 
 Group  Median 
 Overall  Median 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  5-  4.  Noise  Figure  on  Channel  10  (High  VHF) 
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 5-  7 
 5 
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 10 


 A1  D1  E1  G1  H1  D2  E2  G2  J1  M1  R1  A2  A3  B2  D3  F3  L1  P1  R2  G3  I1  I2  J2  K1  L2  M2  N1  O1 
 Receiver 


 Minimum 
 Signal 
 Level 
 (dB 
 above 


 Thermal 


 Noise)  Measurement  Group  Median  Overall  Median 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs 
 $2001  -  $4200 


 Better 


 Worse 


 Figure  5-  5.  Noise  Figure  on  Channel  30  (UHF) 


 10 
 11 
 12 
 13 
 14 
 15 
 16 
 17 
 18 
 19 
 20 


 5678910  1112  1314  15  1617  18  1920  21 
 Noise  Figure  (dB) 


 White 
 Noise 
 Threshold 


 [Required 
 CNR] 
 (dB) 


 Chan  3 
 Chan  10 
 Chan  30 
 Minimum  Signal  Contours 


 Better 


 Worse 


 Better  Worse 
 -84  dBm  -82  dBm  -80  dBm  -78  dBm  -76  dBm 


 -74  dBm 


 -72  dBm 


 Min  Signal  at  TOV  =  -86  dBm 


 -70  dBm 
 -68  dBm 


 Figure  5-  6.  Required  CNR  Versus  Noise  Figure 
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 6-  2 
 the  channel  bandwidth  of  6  MHz  varied  from  -38  to  -28  dBm  based  on  the  level  recorded  in  each  capture.  All  but  four  of  the  captures  played  at  an  in-  channel  level  within  2  dB  of  the  nominal. 
 Successful  playback  of  a  capture  was  defined  in  terms  of  the  number  of  video  error  bursts  observed  during  a  single  playback  loop  after  the  loop  had  played  at  least  three  times.  (In  many  cases  the 
 performance  was  monitored  over  several  loops  and,  if  the  results  varied,  a  median  value  was  chosen.)  A  video  error  burst  lasting  more  than  one  second  was  counted  based  on  the  approximate  duration  in 
 seconds.  Thus,  an  error  burst  lasting  three  seconds  was  counted  as  three  errors.  Errors  occurring  during  or  immediately  after  the  loop-  restart  time  were  not  counted,  nor  were  errors  associated  with  known 
 defects  (dropped  symbols)  in  eight  of  the  captures,  as  documented  by  the  ATSC.  * 
 The  testing  was  performed  on  channel  30.  It  should  be  noted  that  with  many  of  the  DTV  receivers,  simply  tuning  to  channel  30  was  not  sufficient  to  ensure  successful  acquisition  of  the  TV  signal  even 
 with  one  of  the  easier  captures.  The  original  source  material  for  the  captures  was  recorded  from  eight  different  DTV  broadcast  stations  in  two  cities.  Because  of  the  facts  that  multiple  programs  can  be 
 broadcast  on  a  single  channel  and  that  most  DTV  channels  are  associated  with  an  equivalent  analog  channel  number  that  is  used  in  selecting  the  station  (PSIP  requirements),    many  of  the  receivers  were 
 confused  by  changing  broadcast  stations  from  playback  of  one  capture  to  playback  of  the  next,  even  though  the  RF  channel  remained  constant.  As  a  result,  various  methods  such  as  rescanning  the  channels 
 were  necessary  to  get  many  of  the  receivers  to  operate  after  changing  between  captures  that  originated  on  different  TV  channels.  To  save  time  in  the  process,  the  captures  were  sorted  by  originating  broadcast 
 station  before  testing,  and  were  further  sorted  to  allow  the  more  benign  captures  from  a  given  broadcast  station  to  be  played  first,  in  order  to  lock  the  receivers  onto  each  new  broadcast  station. 


 Further  details  on  the  measurement  procedure  are  contained  in  Appendix  A. 
 RESULTS 
 Figure  6-  1  shows  the  results  of  testing  each  DTV  receiver  with  each  of  the  47  RF  captures.  The  general  format  of  the  plot  is  as  described  in  Chapter  3  in  the  section  titled,  Format  of  the  Bar  Graph  Data,  but 


 with  a  few  differences.  The  blue  (lower)  portion  of  each  bar  represents  the  number  of  captures  that  played  without  a  visible  error  during  a  single  loop  of  the  capture.  The  upper  portion  of  each  bar  adds  the 
 captures  that  played  with  no  more  than  two  visible  errors  during  a  single  loop  of  capture. 
 It  should  be  noted  that,  unlike  the  plots  presented  in  earlier  chapters  of  this  report,  increased  performance  in  this  plot  is  represented  by  taller  bars.  Also,  in  addition  to  the  four  category  groupings  of  DTV 
 receivers,  Figure  6-  1  includes  an  additional  bar  on  the  right,  labeled  2000REF.  This  receiver  was  retained  from  field  testing  in  the  year  2000  and  was  included  in  the  RF  capture  testing  presented  here.  Further 
 discussion  of  this  receiver  is  provided  later  in  this  chapter  as  well  as  in  Chapter  7. 


 *  See  Table  B-  1  of  this  report  or  the  Quality  of  Capture  column  of  the  continuation  of  Figure  A-  1  on  p.  28  of 
 ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced  Television  Systems  Committee,  17  June  2004. 


   The  Program  and  System  Information  Protocol  (PSIP)  includes  a  field  for  establishing  this  association.  Further 
 information  is  available  in  Advanced  Television  Systems  Committee  documents  A/  65B  ATSC  Standard:  Program  and  System  Information  Protocol  for  Terrestrial  Broadcast  and  Cable  (Revision  B)  and  A/  69  ATSC 


 Recommended  Practice:  Program  and  System  Information  Protocol  Implementation  Guidelines  for  Broadcasters  for  more  information. 
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 Nominal  Performance  and  Variation  Among  Samples 
 Unlike  the  results  of  other  testing  presented  in  this  report,  the  results  of  testing  against  the  RF  captures  are  heavily  clustered  into  two  major  performance  tiers.  The  upper-  tier  (better)  performers  successfully 


 played  about  29  captures  without  error  and  about  37  captures  with  two  or  fewer  errors.  The  lower-  tier  performers  successfully  played  about  7  captures  without  error  and  about  9  with  two  or  fewer  errors. 
 Neglecting  receivers  D1  and  L2,  all  results  fall  within  2  captures  of  one  of  these  nominal  results,  as  shown  in  Table  6-  1.  Receivers  D1  and,  perhaps,  L2,  appear  to  represent  an  additional  performance  tier 
 slightly  above  the  lower  tier;  this  tier  will  be  designated  as  lower  tier+.  * 
 The  upper-  tier  performers  represent  a  quantum  leap  in  ability  to  handle  the  most  difficult  multipath  conditions.  The  receivers  that  tested  in  this  tier  are  known  to  include  the  latest  generation  of  demodulator 
 chips  from  at  least  two  of  the  major  DTV  chip  developers. 


 Table  6-  1.  Number  of  Captures  Successfully  Played  By  Each  Performance  Tier 
 Number  of  Consumer 


 Receivers  Number  of  Captures  Played  with  No  Errors  Number  of  Captures  Played  with  No  More  Than  2  Errors  Lower  Tier  16  7  2  9  +2/-  1 
 Lower  Tier+  2  8  and  12  14  and  16  Upper  Tier  10  29  2  37  2 


 It  should  be  noted  that  some  of  the  RF  captures  may  contain  recording  flaws  other  than  the  dropped  symbols  discussed  earlier  that  could  prevent  error-  free  demodulation  regardless  of  how  advanced  the 
 demodulator  technology  may  be.  For  example,  four  of  the  captures  for  which  no  tested  receiver  achieved  demodulation  free  of  visual  errors  were  identified  by  the  ATSC  as  having  possible  non-  linearities  caused 
 by  high-  level  adjacent  channels  overdriving  the  recording  system.  These  or  other  potential  flaws  may  preclude  a  100%  success  rate  on  the  47  captures  from  ever  being  achieved  by  any  demodulator; 
 consequently,  we  view  the  multipath-  performance  data  based  on  these  captures  to  be  useful  for  purposes  of  comparing  receivers,  but  not  as  an  absolute  measure  of  performance. 


 Extrapolation  to  the  Three  Captures  Lacking  Video  Content 
 Three  of  the  ATSC-  recommended  RF  captures  lacked  video  content  and  could  not,  therefore,  be  tested  with  the  consumer  DTV  receivers;  however,  they  were  tested  with  a  five-  year-  old  instrumented  DTV 


 receiver,  labeled  2000REF  in  Figure  6-  1.  That  receiver  provides  visual  and  audible  indications  when  segment  errors    occur  during  demodulation  of  the  DTV  signal. 


 Tests  were  performed  first  using  three  captures  with  video  content  (labeled  as  numbers  27,  29,  and  45  in  Appendix  B).  These  captures  exhibited  4,  1,  and  2  visual  errors,  respectively,  with  the  2000REF  receiver. 


 *  Receiver  D1  belongs  in  the  lower  tier+  category  because  it  performed  above  the  range  of  performance  for  the 
 lower  tier  both  in  terms  of  number  of  captures  played  with  no  errors  and  number  of  captures  played  with  two  or  fewer  errors.  The  case  for  placing  receiver  L2  in  the  lower  tier+  category  rather  than  in  the  lower  tier  is  weaker, 


 since  only  one  of  its  performance  numbers  (number  of  captures  played  with  two  or  fewer  errors)  was  above  the  lower  tier  range. 


   With  8-  VSB,  each  transmission  segment  consists  of  one  MPEG  packet.  Thus,  a  segment  error  is  equivalent  to  an 
 MPEG  packet  error. 
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 characterized  by  challenging  multipath  conditions  in  selecting  DTV  receivers  that  achieve  the  upper  tier  of  performance. 
 Relationship  Between  Multipath  Performance  and  White  Noise  Threshold 
 There  is  some  reason  to  expect  that  improvements  in  multipath  performance  which  is  achieved  in  part  by  increasing  the  number  of  taps  in  the  demodulators  equalizer  circuit  might  come  at  the  expense  of 


 poorer  white  noise  threshold,  because,  even  in  the  absence  of  multipath,  the  additional  taps  could  be  expected  to  add  noise  that  is  related  to  carrier  amplitude.  (Since  an  automatic  gain  control  would  be 
 expected  to  provide  sufficient  gain  to  amplify  the  input  signal  whatever  its  level  to  a  fixed  level  for  processing  by  the  demodulator,  one  would  expect  that  the  tap  noise  generated  after  this  variable 
 amplification  would  be  at  a  fixed  level  relative  to  the  DTV  signal  rather  than  at  a  fixed  level  relative  to  the  antenna  input  hence  the  impact  would  appear  as  a  degradation  to  required  CNR  [white  noise 
 threshold]  rather  than  an  increase  in  noise  figure.) 
 Figure  6-  2,  shows  the  measurements  of  white  noise  threshold  (from  Chapter  3)  plotted  against  multipath  performance  as  measured  by  the  number  of  RF  captures  (out  of  47)  that  were  successfully  played  without 
 error.  The  lower  tier  of  multipath  performers  (presumably  containing  earlier  generation  8-  VSB  decoders)  had  a  median  CNR  threshold  of  15.  3  dB,  *  which  is  slightly  worse  than  the  15.  19  dB  threshold  achieved 
 by  the  ACATS  Grand  Alliance  prototype  receiver.    Until  the  most  recent  VSB  decoder  generation  came  to  market,  the  trend  of  the  earlier  VSB  decoder  improvements  was  a  very  slight  worsening  of  the  CNR  at 
 threshold  as  a  tradeoff  for  improved  multipath  performance.  The  15.1  dB  median  CNR  threshold  for  the  upper  tier  of  multipath  performers  suggests  that  this  trend  is  over.  In  fact,  the  seven  best-  performing 
 receivers  in  terms  of  white  noise  threshold  are  in  the  upper  tier  of  multipath  performance. 


 *  15.3  dB  is  the  median  value  for  those  receivers  identified  as  lower  tier  not  including  those  identified  as  lower 
 tier+.  If  the  lower  tier+  receivers  are  included,  the  median  is  15.4  dB. 
   Final  Technical  Report,  Federal  Communications  Commission  Advisory  Committee  on  Advanced  Television 
 Service  (ACATS),  October  31,  1995,  p.  19. 
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 0 
 5 
 10 
 15 
 20 
 25 
 30 
 35 
 40 
 45 


 A1  D1  E1G1  H1  D2  E2G2  J1M1  R1  A2  A3  B2  D3  F3  L1  P1  R2G3  I1  I2  J2  K1  L2M2  N1O1 
 2000REF  Receiver 


 # 
 of 


 RF 
 Captures 


 Successfully 


 Played 
 Back 
 (of 
 47) 


 1-  2  Errors 
 No  Errors 


 STBs  DTVs  $370  -  $1000  DTVs  $1001  -  $2000  DTVs  $2001  -  $4200  Better 


 Worse 
 Figure  6-  1.  Performance  Against  47  RF  Captures 


 14.  8 
 14.  9 
 15.  0 
 15.  1 
 15.  2 
 15.  3 
 15.  4 
 15.  5 
 15.  6 
 15.  7 
 15.  8 
 15.  9 


 0  5  10  15  20  25  30  35 
 #  of  Captures  With  No  Visible  Errors 


 White 
 Noise 
 Threshold 


 [Required 
 CNR] 
 (dB) 


 Better 


 Worse 


 Better  Worse 
 Figure  6-  2.  White  Noise  Threshold  Versus  Multipath  Performance 
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 The  tests  included  six  DTV  receivers,  one  of  which  was  an  instrumented  prototype  receiver  to  be  used  as  a  reference.  Initially,  the  reference  receiver  was  a  second-  generation  Zenith  ProDemodulator.  After  two 
 thirds  of  the  testing  was  complete  (on  July  17,  2000),  that  receiver  was  replaced  with  a  third-  generation  Zenith  ProDemodulator.  The  third  generation  included  an  equalizer  with  longer  ghost  cancellation  times 
 and  slightly  improved  pre-  ghost  performance  at  the  expense  of  slightly  degraded  white  noise  performance,  relative  to  the  second  generation. 


 That  same  third-  generation  receiver  was  tested  this  year,  along  with  the  28  current-  generation  consumer  receivers,  to  determine  performance  against  the  47  RF  captures,  as  described  in  Chapter  6.  The  result  for 
 the  third  generation  reference  receiver  is  shown  as  the  right-  most  bar  (labeled  2000REF)  of  Figure  6-  1.  In  the  current  tests,  that  receiver  with  equalizer  technology  now  two  generations  behind  the  latest 
 technology  tied  for  either  the  worst  or  second  worst  performance  (depending  on  whether  counting  the  zero-  error  data  or  the  two-  error  data)  when  included  with  the  current  crop  of  receivers  that  were  tested. 
 Given  that  the  third  generation  was  used  for  only  one  third  of  the  year-  2000  tests  and  that  a  second  generation  receiver  with  inferior  equalizer  technology  was  used  for  two  thirds  of  those  tests,  one  can 
 assume  that  the  reported  field  test  results  for  the  reference  receiver  from  those  earlier  tests  correspond  to  receiver  with  multipath  performance  at  or  below  the  level  shown  by  the  2000REF  bar  in  Figure  6-  1. 


 In  the  year-  2000  tests,  all  but  one  of  the  51  sites  exhibited  field  strengths  judged  to  be  large  enough  for  theoretical  DTV  reception.  *  Using  the  mast-  mounted,  outdoor-  type  antenna,  the  reference  receiver 
 received  channel  34  with  no  visible  picture  errors  in  all  50  of  those  sites  and  received  channel  48  without  visible  errors  in  49  of  the  50  sites.  Thus,  the  reference  receiver  successfully  handled  multipath  conditions 
 in  99  percent  of  the  test-  site/  broadcast-  station  combinations  with  the  mast-  mounted  antenna.  When  using  the  tripod-  mounted  indoor-  type  antennas  (including  the  Silver  Sensor,  when  needed),  the  reference 
 receiver  handled  85  percent  of  the  test-  site/  broadcast-  station  combinations  without  visible  picture  errors. 
 Thus,  receivers  performing  at  or  below  the  level  of  the  2000REF  receiver  shown  in  Figure  6-  1  were  able  to  successfully  handle  99  percent  of  the  multipath  situations  in  the  coverage  tests  when  using  a  mast-mounted 
 outdoor  antenna.  Though  the  tests  involved  only  one  metropolitan  area  and  the  sample  size  was  too  small  to  consider  these  numbers  statistically  accurate,  the  sites  selected  are  expected  to  be  far  more 
 representative  of  randomly  selected  real  world  conditions  than  the  ATSC-  recommended  sites,  which  were  chosen  because  of  their  difficult  multipath  conditions.  Given  that  the  2000REF  results  show  performance 
 at  or  below  almost  all  of  the  lower-  tier  performers  in  the  Figure  6-  1,  one  can  reasonably  assume  that,  even  lower-  tier  multipath  performance  (as  defined  in  Chapter  6)  is  adequate  to  handle  the  vast  majority  of 
 reception  conditions  (at  least  in  the  Washington,  DC  area)  when  the  receiver  is  paired  with  a  good  outdoor,  mast-  mounted  antenna. 


 Similarly,  receivers  performing  at  or  below  the  level  of  the  2000REF  receiver  shown  in  Figure  6-  1  were  able  to  successfully  handle  85  percent  of  the  multipath  situations  in  the  coverage  tests  when  using  a 
 indoor-  type  antenna  at  a  7-  foot  height  (but  located  outdoors).  It  appears  likely,  then,  that  multipath  performance  at  the  lower  tier  of  Figure  6-  1  may  be  adequate  for  most  locations  in  conjunction  with  an 
 indoor  antenna,  but  that  improved  multipath  performance  (e.  g.,  the  upper  tier  of  Figure  6-  1)  might  offer  benefits  in  many  locations. 


 IMPACT  OF  REPRESENTATIVE  MULTIPATH  ON  REQUIRED  CNR 
 The  year-  2000  field  tests  also  offer  some  insight  into  the  impact  of  multipath  on  required  CNR  for  a  receiver. 


 *  With  the  mast-  mounted  antenna,  51  sites  were  tested.  With  the  tripod-  mounted  antennas,  50  sites  were  tested.  In 
 both  cases,  all  but  one  site  had  sufficient  field  strength  for  theoretical  DTV  reception. 
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 Those  tests  included  measurements  of  required  CNR  at  each  site.  The  required  CNR  was  determined  by  adding  white  Gaussian  noise  to  an  amplified  version  of  the  signal  received  from  the  antenna  and  adjusting 
 the  noise  level  until  the  threshold  of  visibility  (TOV)  was  observed. 
 Though  the  precision  of  the  measurements  was  limited  by  the  use  of  one-  dB  steps  in  adjusting  the  noise  level,  the  median  required  CNR  across  all  of  the  coverage  sites  provides  an  indication  of  the  required 
 CNR  in  real  world  multipath  conditions.  In  general  it  was  found  that  the  newer  generation  receivers  performed  better  i.  e.,  had  a  lower  required  CNR  that  older  generation  receivers.  When  used  with  the 
 mast-  mounted  antenna,  the  newest  generation  receiver  that  was  used  throughout  the  test  period  for  the  2001  report  (a  third  generation  receiver  identified  as  receiver  5  in  that  report)  exhibited  a  median 
 required  CNR  of  15.9  dB  across  all  coverage  sites  tested  for  one  of  the  received  broadcast  stations  and  16.0  dB  for  the  other.  With  the  tripod-  mounted  antennas,  the  corresponding  numbers  were  17.  0  and 
 16.6  dB. 
 Absent  better  information,  a  required  CNR  of  16.0  dB  may  be  a  reasonable  estimate  of  reception  performance  in  typical  multipath  conditions  if  an  outdoor  antenna  is  used. 
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 VARIATION  IN  RECEPTION  PERFORMANCE 
 For  Benign  Signal  Conditions 
 In  the  low-  VHF  band,  the  variation  in  reception  performance  among  the  tested  DTV  receivers  was  moderately  high.  The  minimum  signal  level  at  TOV  exhibited  a  3.7-  dB  standard  deviation  among  the 


 receivers.  89  percent  of  the  receivers  exhibited  performance  within  5.1  dB  of  the  median  performance,  but  two  (seven  percent)  same-  brand  receivers  were  significantly  worse  than  the  median  by  10.6  and 
 12.5  dB.  Omitting  those  two  receivers  from  the  data  set  would  reduce  the  standard  deviation  to  2.3  dB. 
 In  the  high-  VHF  and  the  UHF  bands,  the  variation  in  reception  performance  among  the  tested  receivers  was  small.  In  the  high-  VHF  band,  the  minimum  signal  level  at  TOV  exhibited  a  1.6-  dB  standard 
 deviation;  89  percent  of  the  receivers  exhibited  performance  within  3.1  dB  of  the  median,  and  the  poorest  performing  receiver  exhibited  a  performance  level  4.3  dB  worse  than  the  median.  In  the  UHF  band,  the 
 minimum  signal  level  at  TOV  exhibited  a  0.9-  dB  standard  deviation;  89  percent  of  the  receivers  exhibited  performance  no  worse  than  1.3  dB  poorer  than  the  median,  and  the  poorest  performing  receiver  exhibited 
 a  performance  level  2.5  dB  worse  than  the  median. 
 Most  of  the  variation  in  reception  performance  among  the  tested  receivers  was  due  to  differences  in  receiver  noise  figure  rather  than  in  required  CNR.  The  noise  figure  variations  were  larger  than  the 
 required-  CNR  variations  by  factors  ranging  from  4.2,  in  the  UHF  band,  to  16,  in  the  low-  VHF  band. 


 For  Difficult  Multipath  Conditions 
 Independent  of  band,  there  was  a  wide  variation  in  ability  of  the  receivers  to  handle  difficult  multipath  conditions;  however,  linkage  of  the  current  results  with  earlier  field  test  results  suggest  that  the  observed 


 performance  differences  are  of  no  consequence  in  the  vast  majority  of  reception  locations,  if  an  outdoor,  mast-  mounted  antenna  is  used.  When  an  indoor  antenna  is  used,  the  linkage  suggests  that  the  observed 
 performance  differences  would  be  significant  in  many,  but  probably  not  most,  locations. 
 In  tests  against  RF  captures  recorded  from  antennas  at  sites  specifically  selected  for  their  challenging  multipath  conditions,  the  multipath-  handling  capability  of  the  receivers  fell  primarily  into  two  tiers  of 
 performance.  The  upper  (better-  performing)  tier  included  ten  receivers.  The  lower  tier  included  16  receivers.  Two  receivers  fell  in  between  the  two  tiers,  but  closer  to  the  lower  tier.  The  upper-  tier 
 receivers  were  able  to  handle  about  four  times  as  many  of  the  RF  captures  as  the  lower  tier. 
 The  FCCs  year-  2000  field  tests  at  51  sites  that  were  selected  without  regard  to  multipath  and  thus  more  likely  to  be  representative  of  the  typical  range  of  common  reception  conditions  than  the  RF  captures  can 
 be  used  to  put  the  current  multipath  test  results  in  perspective.  A  now-  obsolete  instrumented  receiver  left  over  from  those  earlier  field  tests  was  retested  this  year  against  the  RF  captures  and  was  found  to  perform 
 at  the  bottom  of  the  lower  performance  tier.  But,  in  the  year  2000  field  tests  that  now-  inferior  receiver  successfully  handled  multipath  in  99%  of  the  combinations  of  site  and  broadcast  station,  *  when  a  mast-mounted 
 outdoor  antenna  was  used.  The  success  rate  dropped  to  85  percent  when  an  indoor-  type  antenna  was  used,    indicating  an  increased  likelihood  that  better  multipath  performance  in  the  receiver  would  have 
 helped. 


 *  Out  of  the  50  sites  that  had  sufficient  field  strength  for  theoretical  DTV  reception. 
   The  indoor  antenna  was  mounted  at  a  7-  foot  height,  consistent  with  indoor  antenna,  but  tests  were  performed 
 outdoors. 
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 PRICE-  DEPENDENCE  OF  RECEPTION  PERFORMANCE 
 For  Benign  Multipath  Conditions 
 In  assessing  the  price-  dependence  of  receiver  performance,  one  must  consider  two  things:  (1)  whether  an  observed  variation  of  performance  with  price  among  the  tested  receivers  is  statistically 


 significant  i.  e.,  whether  it  represents  a  real  trend  among  DTV  receivers  currently  on  the  market  or  whether  it  is  a  statistical  artifact  of  the  particular  selection  of  receivers  that  were  tested;  and, 
 (2)  whether  an  observed  variation  of  performance  with  price  is  of  sufficient  magnitude  to  significantly  affect  television  performance. 


 In  the  low-  VHF  band,  though  the  variability  in  performance  among  the  receivers  was  moderately  high,  the  variability  among  the  price  categories  was  small,  and  no  statistically  significant  price-  dependence  of 
 that  variation  was  found.  In  fact,  the  median  performance  of  the  low-  cost  TVs  was  slightly  better  than  that  of  either  the  mid-  priced  or  high-  priced  TVs.  The  median  performance  of  the  tested  set-  top  boxes  was 
 poorer  than  that  of  the  integrated  DTVs  by  2.3  dB,  though  it  must  be  noted  that  these  were  older  designs  (2004  and  earlier  models  that  were  still  on  the  market  at  the  time  of  this  report)  than  the  DTVs. 


 In  the  high-  VHF  and  the  UHF  bands,  the  variation  in  reception  performance  with  price  was  judged  to  be  both  small  and  not  statistically  significant.  The  median  performance  of  the  high-  cost  TVs  differed  from 
 that  of  the  low-  cost  TVs  by  less  that  0.2  dB.  Set  top  boxes  exhibited  median  performance  0.6  dB  and  0.7  dB  worse  than  the  median  of  all  TVs  in  the  low-  VHF  and  UHF  bands,  respectively. 


 For  Difficult  Multipath  Conditions 
 The  tested  receivers  fell  into  two  distinct  tiers  of  multipath-  handling  capability  the  upper  tier  representing  a  significant  performance  improvement  associated  with  at  least  two  companies  newest 


 generation  of  demodulator  chips. 
 Given  that  both  tiers  of  performance  appeared  in  all  three  price  ranges  of  DTV  receivers,  there  appears  to  be  no  inherent  price  dependence  among  the  DTVs;  however,  there  was  a  complete  absence  of  upper-  tier 
 performers  among  the  tested  set-  top  boxes.  This  absence  is  attributed  to  the  older  designs  of  the  set-  top  box  products  all  of  which  were  introduced  in  the  year  2004  or  earlier.  Among  the  tested  receivers,  none 
 that  were  introduced  before  March  2005  were  found  to  exhibit  upper-  tier  performance,  whereas  48  percent  of  those  introduced  in  or  after  that  month  performed  at  the  upper  tier  level. 


 RECEPTION  PERFORMANCE  RELATIVE  TO  OET-  69 
 For  Benign  Multipath  Conditions 
 The  results  show  no  clear  need  to  adjust  planning  factors  in  OET-  69  for  application  to  SHVERA.  Table  8-  1  shows  that,  for  benign  multipath  conditions,  the  poorest  performing  receiver  category  set-  top 


 boxes  exhibited  median  performance  (as  indicated  by  minimum  signal  at  TOV)  closely  matching  predictions  based  on  current  OET-  69  planning  factors,  with  median  performance  exceeding  the  OET-  69 
 predictions  by  1.7  dB  in  high  VHF  and  falling  below  OET-  69  performance  levels  by  less  than  1  dB  in  low  VHF  and  UHF.  The  median  low-  cost  DTV  performance  matched  OET-  69  in  the  UHF  band  and  was 
 better  than  OET-  69  by  about  2  dB  in  the  VHF  bands.  It  should  be  noted  that  the  tolerance  on  these  measurements  is  about  1  dB. 
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 [It  is  also  noted  that,  in  terms  of  minimum  signal  at  TOV,  the  overall  median  performance  of  the  tested  receivers  (-  82.2,  -83.2,  and  -83.9  dBm,  in  low  VHF,  high  VHF,  and  UHF,  respectively)  matches,  within 
 measurement  accuracy,  the  minimum  performance  standard  of  -83  dBm  recommended  by  the  ATSC.  *  ] 


 Table  8-  1.  Net  Performance  for  Unimpaired  Signal  Relative  to  OET-  69  Model 


 Band  Median  of  All  Test  Samples  Median  Low-  Cost  DTV  Median  Set-  Top  Box  Low  VHF  (Ch.  3)  1.2  dB  better  2.3  dB  better  0.7  dB  worse 
 High  VHF  (Ch.  10)  2.2  dB  better  2.4  dB  better  1.7  dB  better  UHF  (Ch.  30)  0.1  dB  worse  0.1  dB  better  0.8  dB  worse 


 A  breakdown  of  the  results  by  individual  planning  factors  is  shown  in  Table  8-  2.  Median  required  carrier-  to-  noise  ratios  (CNRs)  closely  match  the  OET-  69  value,  as  does  the  system  noise  figure  in  UHF. 
 The  median  VHF  noise  figures  of  the  tested  receivers  were  better  than  the  OET-  69  values,  with  the  exception  of  the  set-  top  box  median  in  low  VHF,  which  was  only  0.  5  dB  above  (worse  than)  the  OET-  69 
 value. 


 Table  8-  2.  Planning  Factor  Measurements  with  Unimpaired  Signal 


 Planning  Factor  OET-  69 
 Overall  Median  of 
 Test  Samples 
 Median  Low-  Cost 
 DTV 
 Median  Set-  Top 
 Box  Required  Carrier-  to-Noise 


 Ratio  (dB)  15.2 
   15.3  15.3  15.4 


 System  Noise  Figure  (dB)  in  Low  VHF  10.0  8.8  7.4  10.5 
 System  Noise  Figure  (dB)  in  High  VHF  10.0  7.6  7.5  7.8 
 System  Noise  Figure  (dB)  in  UHF  7.0  6.9  6.9  7.5 


 Note:  for  all  parameters,  lower  values  correspond  to  better  performance 
 Adjustment  for  Multipath 
 The  required  CNRs  presented  above  were  measured  for  an  unimpaired  signal.  In  the  presence  of  significant  multipath,  it  is  known  that  higher  CNRs  are  required.  We  have  performed  no  measurements  of 


 this  effect  on  the  current  generation  of  receivers;  however,  field  tests  from  the  year  2000  yielded  a  value  of  16  dB  for  the  median  required  CNR  across  50  test  sites  using  the  then  newest  generation  of  DTV 
 receiver  hardware  and  an  outdoor,  mast-  mounted  antenna.  This  is  only  0.7  dB  above  the  median  measured  value  from  the  receiver  tests  using  a  benign  signal.  If  the  net  performance  data  of  Table  8-  1 
 were  degraded  by  0.7  dB  to  reflect  this  value  for  required  CNR,  it  can  be  seen  that  the  results  would  still  closely  match  OET-  69  predictions. 


 *  ATSC  Recommended  Practice:  Receiver  Performance  Guidelines,  ATSC  Doc.  A/  74,  Advanced  Television 
 Systems  Committee,  17  June  2004,  p.  11. 
   See  note  for  Table  1-  1. 
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 Overall  Conclusion  Regarding  Adjustment  to  Planning  Factors 
 While  adjustments  to  the  OET-  69  planning  factors  could  be  made  based  on  the  test  results  presented  in  this  report  in  combination  with  results  from  the  year-  2000  field  tests,  the  overall  effect  on  performance 


 predictions  would  be  small.  Combining  the  16-  dB  required  CNR  value,  as  discussed  above,  with  the  overall  median  noise  figures  would  yield  more  optimistic  predictions  that  the  current  OET-  69  by  0.4  dB 
 and  1.6  dB,  respectively,  in  the  low-  VHF  and  high  VHF  bands,  and  less  optimistic  predictions  by  0.7  dB  in  the  UHF  band.  Given  the  tolerances  on  the  measurements,  such  adjustments  to  the  existing 
 methodology  are  not  recommended. 
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 APPENDIX  A:  TEST  CONFIGURATIONS,  ISSUES,  AND  PROCEDURES 
 TEST  CONFIGURATIONS 
 This  appendix  provides  additional  information  regarding  test  configurations,  procedures,  and  issues  that  arose  during  the  testing. 


 General  Information  on  the  Test  Configurations 
 All  test  and  measurement  setups  maintained  a  50-  ohm  impedance  throughout,  except  at  the  signal  source  and  the  consumer  TV  inputs,  which  were  each  specified  to  be  nominally  75  ohms.  (An  older, 


 instrumented  reference  receiver  identified  as  2000REF  in  this  report  had  a  50  ohm  input  impedance.)  The  75-  ohm  devices  were  matched  to  the  rest  of  the  test  setup  through  minimum-  loss  impedance-  matching 
 pads,  except  that,  in  the  test  setup  that  employed  a  splitter,  an  impedance-  matching  transformer  was  used  at  the  signal  source  to  reduce  losses. 


 Attenuation  pads  were  used  throughout  each  test  configuration  to  reduce  the  effects  of  any  impedance  mismatches  at  places  where  such  mismatches  were  considered  likely  or  would  be  expected  to  have  a 
 significant  impact.  A  50-  to-  75-  ohm  impedance-  matching  pad  used  at  the  input  of  each  consumer  DTV  receiver  served  both  as  an  impedance-  matching  device  and  as  a  5.8-  dB  attenuator  to  attenuate  reflections 
 due  to  deviations  of  the  TV  antenna  inputs  from  the  nominal  75-  ohm  value.  * 


 Splitter  Test  Configuration 
 Figure  A-  1  shows  a  block  diagram  of  the  splitter  test  configuration,  which  was  used  for  tests  of  white  noise  threshold  and  multipath  performance. 


 An  RF  player  (Sencore  RFP-  910)  playing  the  Hawaii_  ReferenceA  file  supplied  with  the  player  was  used  as  the  ATSC  8-  VSB  signal  source,  for  reasons  discussed  in  the  Test  Issues  section  of  this 
 appendix.  Amplifiers  for  the  signal  operated  at  RMS  levels  that  were  more  than  17-  dB  below  the  specified  1-  dB  compression  points  in  order  to  ensure  linearity. 


 For  the  white  noise  tests,  noise  was  supplied  by  a  noise  generator,  which  was  then  externally  filtered  to  roll  off  the  noise  beyond  700  MHz  well  above  the  tested  frequencies. 
 Both  signal  and  noise  levels  were  adjusted  using  step  attenuators  that  could  provide  0  to  81  dB  of  attenuation  in  0.1-  dB  steps. 
 Signal  and  noise  were  combined  using  a  directional  coupler,  then  divided  nine  ways  by  means  of  two  cascaded  layers  of  three-  way  splitters,  each  specified  to  have  a  minimum  isolation  of  14  dB  between 
 inputs.  The  splitters  were  followed  by  25-  foot  long,  well-  shielded,  low-  loss  cables,  each  of  which  drove  either  an  impedance-  matching  pad  (nominally  5.8-  dB  power  attenuation)  for  connection  to  a  consumer 
 TV  receiver  or  a  50-  ohm  attenuator  pad  (nominally  6-  dB  attenuation)  for  connection  to  measuring  instruments  or  to  the  instrumented  receiver.  The  nine  outputs  at  the  output  of  the  final  pads  are 
 designated  by  port  numbers  Pt1,    Pt9  when  the  final  pad  is  an  impedance-  matching  pad,  as  when  driving  a  consumer  DTV.  An  a  is  suffixed  onto  the  port  numbers  when  the  final  pad  is  a  50-  ohm  pad, 


 *  The  intent  was  both  to  minimize  standing  waves  on  the  25-  foot,  low-  loss  cables  and  to  reduce  the  impact  of  RF 
 energy  reflected  back  from  a  poorly  matched  TV  on  signals  delivered  to  other  TVs  through  the  splitter. 
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 as  when  driving  a  measurement  instrument  (vector  signal  analyzer  or  spectrum  analyzer)  or  an  instrumented  receiver  having  a  50-  ohm  input  impedance.  Port  Pt5a  was  always  used  as  the  measurement 
 port. 
 The  splitter  arrangement  allowed  the  signal  and  noise  to  be  simultaneously  delivered  to  as  many  as  eight  TVs  and  to  a  vector  signal  analyzer  used  for  measurements.  Any  amplitude  mismatch  between  the 
 various  ports,  though  small,  was  not  of  concern  because  the  signal  levels  for  multipath  testing  were  not  critical  and  because  white  noise  threshold  tests  involve  the  ratio  of  two  measurements  (signal  and  noise) 
 that  were  made  on  the  same  port  and  using  the  same  amplitude  range  of  the  spectrum  analyzer  to  eliminate  the  effect  of  small  errors  in  absolute  measured  levels. 


 Minimum  Signal  Test  Configuration 
 Figure  A-  2  is  a  block  diagram  of  the  configuration  used  for  measuring  minimum  signal  at  TOV. 


 An  RF  player  (Sencore  RFP-  910)  playing  the  Hawaii_  ReferenceA  file  supplied  with  the  player  was  used  as  the  ATSC  8-  VSB  signal  source,  for  reasons  discussed  in  the  Test  Issues  section  of  this 
 appendix. 
 Because  minimum  input  signal  at  TOV  is  an  absolute  measurement  rather  than  a  ratio,  a  signal  splitter  was  not  used  for  these  tests.  The  25-  foot  low-  loss  coaxial  cable  carrying  the  signal  was  connected 
 through  a  10  dB  attenuator  and  an  impedance  matching  pad  (50  to  75  ohms,  5.8  dB  power  attenuation)  to  the  TV  input.  After  signal  level  was  adjusted  to  achieve  TOV  on  the  TV,  the  cable  and  10-  dB  pad  but 
 not  the  impedance  matching  pad  were  moved  to  the  vector  signal  analyzer  input  for  the  signal  level  measurement,  which  then  had  to  be  corrected  for  measured  loss  of  the  impedance  matching  pad. 


 CALIBRATION  AND  SIGNAL  QUALITY  TESTS  ON  TEST  SETUPS 
 Impedance-  Matching  Devices 
 The  power  loss  of  14  identical  minimum-  loss  impedance-  matching  pads  (Trilithic  model  ZM-  57)  and  two  impedance-  matching  transformers  (Trilithic  ZMT-  57)  were  measured  as  a  function  of  frequency.  The 


 devices  were  labeled  with  individual  numbers  for  identification;  designations  were  MLP#  1  through  MLP#  14  for  the  minimum-  loss  impedance-  matching  pads  and  TT#  1  and  TT#  2  for  the  transformers. 


 The  losses  of  the  individual  impedance  matching  devices  were  determined  from  loss  measurements  performed  on  back-  to-  back  pairs  of  impedance-  matching  devices.  These  measurements  were  performed 
 by  measuring  signal  levels  versus  frequency  for  a  tracking  generator  signal  and  for  that  signal  as  attenuated  by  a  back-  to-  back  pair  of  impedance-  matching  devices  (50  ohms  to  75  ohms  to  50  ohms)  to 
 determine  the  loss  versus  frequency  for  each  tested  pair  of  devices.  (Loss  was  computed  by  subtracting  the  measured  output  level  versus  frequency  of  the  tested  devices  from  the  output  level  versus  frequency  of 
 the  tracking  generator,  measured  with  the  same  spectrum  analyzer  settings  [including  input  attenuation  and  reference  level]  in  order  to  ensure  that  loss  measurements  were  accurate.)  The  measured 
 combinations  included  MLP#  13  with  each  of  the  other  devices  and  MLP#  14  with  each  of  the  other  devices.  The  difference  between  losses  of  MLP#  13  and  MLP#  14  was  computed  as  the  difference 
 between  average  loss  of  the  combinations  of  MLP#  13  with  MLP#  1  through  MLP#  12  and  average  loss  of  the  combinations  of  MLP#  14  with  MLP#  1  through  MLP#  12.  The  loss  of  MLP#  13  combined  with 
 MLP#  14  determined  the  sum  of  losses  of  MLP#  13  and  MLP#  14.  Combining  this  information  allowed  computation  of  the  individual  losses  of  MLP#  13  and  MLP#  14.  The  loss  of  each  of  the  other  devices 
 could  then  be  computed  by  subtracting  the  loss  of  MLP#  13  from  the  measured  loss  of  the  combination  of 
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 that  device  with  MLP#  13,  or  by  performing  a  similar  calculation  based  on  MLP#  14;  in  fact,  both  computations  were  performed  and  the  results  averaged  to  determine  the  loss  of  those  devices. 
 The  unit-  to-  unit  variation  of  the  loss  of  the  impedance  matching  pads  at  channel-  30  frequencies  was  of  interest  because  of  their  use  in  the  splitter  test  setup.  The  pads  were  found  to  be  quite  well  matched 
 with  samples  ranging  from  5.79  to  5.84  dB  at  the  frequency  of  TV  channel  30. 
 All  of  the  pads  and  both  transformers  were  found  to  be  flat  to  within  0.02  dB  across  the  6-  MHz  bandwidths  of  each  tested  channel  (3,  10,  and  30). 


 TV-  channel-  specific  measurements  of  absolute  loss  of  one  impedance  matching  pad  (MLP#  12)  were  used  in  determining  minimum  signal  at  TOV  because  the  actual  signal  level  measurement  did  not  include  the 
 loss  of  that  pad.  Those  losses  were  5.70,  5.73,  and  5.82  dB,  respectively,  on  channels  3,  10,  and  30. 
 The  frequency-  dependent  measurements  of  the  loss  of  one  impedance-  matching  transformer  (TT#  1)  were  used  in  determining  the  frequency  response  of  the  splitter  test  configuration  to  the  50-  ohm  outputs  (Pt5a 
 and  Pt8a). 


 Splitter  Test  Configuration 
 Because  of  the  complexity  of  the  splitter  test  configuration,  which  included  amplifiers,  a  noise  generator,  a  directional  coupler,  and  splitters  that  were  not  a  part  of  the  simpler  minimum-  signal  test  configuration, 


 additional  tests  were  performed  to  verify  its  performance.  The  tests  evaluated  the  frequency  response  (including  the  potential  effect  of  errors  in  input  impedance  of  the  TVs),  port-  to-  port  matching,  signal  and 
 noise  spectral  characteristics,  and  signal  quality. 
 Frequency  Response  and  Effect  of  Mismatched  Loads 
 The  splitter  test  configuration  (Figure  A-  1)  provided  nine  identical  output  ports,  each  of  which  could  be  configured  for  connection  to  a  75-  ohm  device  (the  antenna  port  of  a  consumer  DTV)  or  to  a  50-  ohm 


 device  (vector  signal  analyzer,  spectrum  analyzer,  or  an  instrumented  reference  receiver  having  50  ohms  input  impedance).  Configuration  of  each  port  was  performed  by  connection  of  either  an  impedance-matching 
 pad  (50  to  75  ohms,  5.8  dB  nominal  power  attenuation)  or  a  50-  ohm  pad  (6  dB  0.  5  dB)  at  the  final  output  of  the  port  (end  of  the  25-  foot  low  loss  cable).  The  ports  were  designated  Pt1,    Pt9  when 
 matched  to  75  ohms.  A  suffix  a  was  added  to  the  designation  of  ports  matched  to  50  ohms.  Only  two  ports  were  ever  configured  for  50  ohms  during  the  reported  tests:  the  fifth  port  (Pt  5a),  which  always 
 served  as  the  measurement  port;  and  the  eight  port  (designated  Pt8a,  when  so  configured),  which  was  used  to  connect  to  the  instrumented,  50-  ohm  input  receiver  designated  2000REF  for  one  set  of  tests. 


 Figure  A-  3  shows  the  frequency  response  of  the  entire  test  setup  from  the  output  of  the  ATSC  signal  source  (PtA  in  Figure  A-  1)  to  each  of  the  final  output  ports.  For  port  8,  separate  results  are  shown  for  the 
 Pt8  and  Pt8a  configurations.  During  the  measurements,  all  ports  except  that  being  measured  were  terminated  in  the  appropriate  impedance  either  50  or  75  ohms.  The  response  of  each  port  was  flat  to 
 well  within  0.1  dB  (maximum    minimum)  across  the  6-  MHz  bandwidth  of  TV  channel  30.  The  gain  of  each  75-  ohm  port  matched  that  of  the  measurement  port  (Pt5a)  within  0.2  dB. 


 A  test  was  also  performed  to  determine  whether  frequency  response  on  one  port  would  be  significantly  affected  by  impedance  mismatches  on  other  ports,  since  consumer  TVs  may  not  have  carefully  controlled 
 input  impedance.  Figure  A-  4  shows  three  frequency  response  plots  measured  on  Port  Pt5a  under  three  different  load  conditions  for  the  other  eight  ports:  ideal  terminations  (75  ohms),  actual  TVs  (tuned  to 
 channel  30),  and  open  circuits.  With  TVs  as  loads  the  frequency  response  across  channel  30  remained  flat  to  well  within  0.1  dB.  With  open  circuits  on  all  eight  ports,  flatness  degraded  somewhat,  but  was  still 
 well  within  0.2  dB  across  channel  30. 
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 All  of  the  above  tests  were  performed  by  using  a  spectrum  analyzer  and  tracking  generator,  as  shown  in  Figure  A-  5.  In  all  cases  the  tracking  generator  signal  (connected  through  an  attenuator  pad  to  stabilize  the 
 impedance)  was  injected  at  PtB  in  Figure  A-  1  so  that  a  50-  ohm  source  could  be  used.  For  frequency  response  tests  of  75-  ohm  ports,  the  losses  in  TT#  1,  the  impedance-  matching  transformer  that  normally 
 connected  the  75-  ohm  ATSC  source  to  PtB,  were  included  by  using  TT#  1  to  match  the  impedance  of  the  selected  port  to  the  50-  ohm  input  of  the  spectrum  analyzer.  For  frequency  response  tests  of  50-  ohm  ports, 
 TT#  1  was  omitted  from  the  measurement,  but  its  losses  as  a  function  of  frequency  (measured  separately)  were  included  in  the  computed  frequency  response.  In  all  cases,  the  tracking  generator  signal  as 
 attenuated  by  the  10-  dB  pad  shown  in  Figure  A-  5  was  measured  by  the  spectrum  analyzer  as  a  reference  in  the  frequency  response  calculations.  All  measurements  were  performed  with  the  same  spectrum 
 analyzer  settings  (including  input  attenuation  and  reference  level)  in  order  to  ensure  accuracy  of  the  computed  frequency  response  function.) 


 Signal  Spectrum,  Noise  Spectrum,  and  Signal  Quality 
 Spectrum  and  modulation  error  ratio  measurements  indicate  that  a  high  quality  test  signal  and  spectrally  flat  noise  were  delivered  to  the  output  ports  of  the  test  setup. 


 Figure  A-  6  shows  spectra  of  the  injected  signal  and  noise  as  measured  at  Pt5a  during  playback  of  the  Hawaii_  ReferenceA  file  from  the  RF  capture  player  at  a  CNR  of  15  dB.  The  spectra  were  measured 
 with  a  30-  kHz  resolution  bandwidth,  300-  kHz  video  bandwidth,  RMS  detection,  and  trace-  averaging  (in  linear  power  units)  of  8192  traces.  (This  averaging  was  performed  across  multiple  loops  of  the  test 
 signal).  The  noise  spectrum  is  flat  across  the  6-  MHz  bandwidth  of  TV  channel  30  to  within  0.34  dB  (maximum    minimum)  for  the  spectrum  as  shown  and  to  within  0.11  dB  when  a  500-  kHz  smoothing 
 width  is  applied  to  average  out  some  of  the  randomness  of  the  measurement.  Similarly,  the  signal  spectrum  is  flat  across  the  4.76-  MHz  wide  head  (i.  e.,  flat  part)  of  the  ATSC  signal  to  within  0.59  dB  for 
 the  spectrum  as  shown  and  0.38  dB  when  500-  kHz  smoothing  is  applied. 
 Modulation  error  ratio  (MER)  measured  by  the  vector  signal  analyzer  during  the  tests  of  required  CNR  was  a  respectable  33  to  35  dB  without  including  any  equalization  in  the  vector  analyzer  and  37  dB  with 
 equalization. 
 Other  Checks 
 A  test  was  performed  to  ensure  that  any  impedance  mismatch  at  PtC  in  Figure  A-  1  would  not  affect  the  level  of  injected  noise  from  the  noise  generator  through  the  resulting  variations  in  impedance  at  the  signal 


 input  to  the  directional  coupler  as  the  signal  step  attenuator  was  varied.  The  noise  level  step  attenuator  was  adjusted  to  achieve  -70  dBm  noise  level  at  Pt5a.  Amplifier  A2  was  then  replaced  by  a  short  circuit  at 
 PtC  and  the  noise  level  at  Pt5a  was  measured  for  two  different  settings  of  the  signal  attenuator  0  dB  and  81  dB.  The  measured  variation  in  noise  power  was  only  0.01  dB. 


 To  ensure  that  amplifier  A2  (Figure  A-  1)  was  not  operated  in  a  non-  linear  region  that  might  affect  signal  quality,  the  signal  level  at  the  output  of  A2  was  measured  during  playback  of  the  Hawaii_  ReferenceA 
 file.  The  measured  level  was  17.5  dB  below  the  1-  dB  compression  point  of  the  amplifier. 
 Signal-  to-  noise  ratio  of  the  signal  path  (excluding  any  noise  generated  by  the  RF  player)  was  measured  to  ensure  that  amplifier  noise  (from  A1  and  A2  in  Figure  A-  1)  did  not  significantly  affect  results.  SNR  in  a 
 6-  MHz  bandwidth  was  found  to  be  64  dB  on  channel  30. 


 TEST  ISSUES 
 A  few  observations  regarding  issues  that  arose  during  the  test  program  may  be  of  value  to  others  who  perform  DTV  receiver  performance  testing. 
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 Multipath  Performance  Testing  Using  the  RF  Player 
 After  we  had  tested  16  DTV  receivers  against  each  of  the  47  RF  captures,  visiting  engineers  from  a  DTV  chipset  developer  (ATI  Research)  observed  video  errors  on  one  of  the  TVs  during  playback  of  a  few 


 captures.  Though  all  tested  TVs  were  able  to  play  some  of  the  captures  with  no  visible  errors,  the  visiting  engineers  suggested  that  the  errors  observed  on  some  specific  captures  indicated  that  the  FCCs  RF  player 
 was  not  functioning  properly.  This  conclusion  was  based  on  two  factors:  (1)  they  had  tested  a  TV  with  the  same  technology  at  their  labs  and  found  it  had  produced  no  visible  errors  on  those  specific  captures; 
 (2)  they  reported  having  had  problems  with  several  of  their  own  RF  capture  players  that  produced  visible  errors  which  went  away  after  calibration  and  repair  of  the  player. 


 Based  on  these  observations,  we  sent  our  RF  player  back  to  the  manufacturer  for  repair  and  calibration;  the  manufacturer  indicated  that  our  problem  had  been  caused  by  a  ground  plane  error  on  one  of  the  cards. 
 After  they  replaced  that  card  and  recalibrated  the  unit,  the  difference  was  dramatic.  A  TV  that  had  successfully  handled  only  10  of  the  captures  with  no  visible  errors  before  the  repair  was  able  to  handle  31 
 of  the  captures  without  visible  errors  after  the  repair.  We  subsequently  discarded  all  previous  results  and  repeated  all  testing. 


 As  an  additional  confirmation  of  performance  of  our  RF  player  in  conjunction  with  our  entire  splitter-based  test  setup,  ATI  allowed  us  to  test  two  DTV  samples  (subsequently  identified  as  upper  tier 
 performers  in  Chapter  6)  at  their  laboratories  using  their  equipment.  The  net  test  results  (number  of  captures  played  with  no  visible  errors  and  number  played  with  no  more  than  two  visible  errors)  at  the 
 FCC  using  our  test  setup  with  our  repaired  RF  player  matched  those  that  we  performed  at  ATI  for  one  of  the  TVs.  For  the  other  TV,  the  tests  at  the  FCC  showed  three  more  captures  producing  two  or  fewer 
 errors  (including  zero  errors),  but  showed  two  fewer  captures  producing  no  errors.  Given  the  variability  in  results  that  sometimes  occur  between  playback  loops  along  with  the  subjective  judgment  in  identifying 
 visual  errors,  these  differences  were  considered  acceptable. 


 RF  Source  for  Measurements  of  White  Noise  Threshold  and  of  Minimum  Signal 
 Our  plan  had  been  to  use  the  RF  player  as  an  ATSC  source  only  when  performing  multipath  testing.  An  ATSC  signal  generator  was  to  be  used  for  testing  of  white  noise  threshold  and  of  minimum  signal  at 


 TOV. 
 In  initial  tests  of  16  DTV  receivers  using  the  signal  generator  as  a  source,  the  white  noise  threshold  of  the  best  tested  receiver  was  found  to  be  15.  25  dB.  This  was  slightly  higher  than  the  14.9  to  15.  0  dB  that  had 
 been  expected  for  the  better-  performing  receivers;  consequently,  the  generator  was  sent  back  to  its  manufacturer  for  calibration  and  checkout.  Upon  its  return,  retesting  of  that  best  performing  receiver 
 yielded  a  white  noise  threshold  16.0  dB  indicating  degraded  signal  quality. 
 After  the  poor  result  with  the  signal  generator,  white  noise  threshold  was  measured  again,  but  this  time  using  the  RF  player  and  a  laboratory-  recorded  DTV  signal  file  designated  Hawaii_  ReferenceA  as  the 
 signal  source.  The  measured  white  noise  threshold  of  that  same  receiver  was  then  found  to  be  14.94  dB.  Based  on  these  results,  the  ATSC  signal  generator  was  replaced  by  the  RF  player,  which  was  then  used 
 for  all  testing  reported  herein.  (Previous  test  results  were  discarded  and  all  tests  were  repeated.) 


 Getting  DTV  Receivers  to  Recognize  a  DTV  Signal 
 The  channel-  selection  intelligence  of  many  DTVs  combined  with  certain  artificialities  of  laboratory-based  testing  to  create  some  challenges. 


 With  analog  television,  to  receive  a  signal  on  a  given  TV  channel  you  simply  select  that  channel.  With  DTV,  there  is  another  layer  involved  channel  selection.  To  simplify  the  DTV  transition  for  the  consumer, 
 a  DTV  signal  includes  coding  that  tells  the  TV  the  channel  number  of  the  analog  station  that  is  associated 
124
 Federal  Communications  Commission  FCC  05-  199 
 A-  6 
 with  that  DTV  signal.  In  Washington,  DC,  for  example,  the  DTV  broadcast  on  channel  48  includes  information  linking  it  to  an  analog  broadcast  on  channel  4.  A  TV  viewer  not  aware  of  the  digital 
 broadcast  on  channel  48  can  tune  to  a  channel  he  or  she  may  already  view  channel  4  and  the  digital  television  will  automatically  set  its  tuner  to  channel  48  to  select  the  digital  broadcast  containing  the  same 
 programming  as  the  viewer  would  have  seen  on  analog  channel  4. 
 To  facilitate  this  extra  layer  in  channel  selection,  DTVs  include  a  channel  scan  function  that  is  used  on  initial  setup  of  the  TV.  The  function  causes  the  tuner  to  sequence  through  all  TV  channels  searching  for 
 analog  and  digital  signals.  It  creates  a  mapping  from  the  analog  channel  numbers  to  the  digital  ones  and  may  also  identify  available  sub-  channels  on  each  DTV  broadcast,  since  the  DTV  transmission  system 
 enables  transmission  of  more  than  one  program  within  a  single  RF  TV  channel.  Many  of  the  TVs  will  not  allow  a  DTV  signal  to  be  received  unless  it  has  been  identified  by  such  a  scan. 


 The  laboratory  tests  described  in  this  report  created  two  types  of  anomalies  one  associated  with  the  tests  of  minimum  signal  at  TOV  and  the  other  associated  with  multipath  testing  using  the  RF  captures. 
 The  minimum  signal  tests  were  performed  on  channels  3,  10,  and  30.  The  available  equipment  allowed  creation  of  the  signal  on  only  one  channel  at  a  time;  consequently,  any  channel  scan  identified  only  one 
 channel,  and  when  the  channel  was  changed  for  the  next  set  of  tests,  the  channel  scan  had  to  be  repeated. 
 For  the  multipath  testing,  a  less  obvious  problem  occurred.  All  testing  was  performed  on  channel  30,  so  one  might  expect  that  a  single  channel  scan  on  each  TV  would  enable  testing  with  all  47  captures.  While 
 this  worked  for  some  TVs,  it  did  not  for  others.  The  original  source  material  for  the  captures  was  recorded  from  eight  DTV  channels  in  two  cities.  Many  of  the  receivers  were  confused  by  changing 
 broadcast  stations  (from  one  capture  to  the  next),  even  though  the  RF  channel  remained  constant.  Many  would  not  allow  selection  of  the  signal  as  channel  30;  instead,  the  signal  had  to  be  tuned  indirectly  by 
 selecting  the  channel  number  of  the  analog  broadcast  associated  with  the  recorded  digital  broadcast  which  could  only  occur  after  a  channel  scan. 


 Thus,  each  time  that  an  RF  capture  was  loaded,  if  it  originated  from  a  different  broadcast  station  from  the  last,  steps  had  to  be  taken  to  ensure  that  each  TV  recognized  the  new  signal.  The  necessary  steps  varied 
 among  the  TVs.  Some  immediately  displayed  the  new  video.  For  others,  simply  pressing  the  channel  up  or  down  button  caused  the  signal  to  be  selected.  For  TVs  requiring  a  new  channel  scan,  some  allowed  the 
 user  to  select  a  single  channel  number  to  rescan  (channel  30  in  this  case),  while  other  required  a  more  time  consuming  rescan  of  all  channels.  For  some  TVs,  even  a  complete  rescan  was  not  sufficient  to  lock 
 in  the  new  signal;  unplugging  the  TV  from  its  power  source  followed  by  a  channel  rescan  was  usually  sufficient  in  those  cases. 


 To  save  time  in  the  multipath  testing  process,  the  captures  were  sorted  by  originating  broadcast  station  before  testing.  This  reduced  the  number  of  transitions  between  broadcast  sources  so  that  fewer  channel 
 scans  would  be  necessary.  To  further  assist  in  testing,  the  captures  were  sorted  within  each  originating  channel  group  to  allow  the  more  benign  captures  from  a  given  broadcast  station  to  be  played  first  in 
 order  to  lock  the  receivers  onto  each  new  broadcast  station  using  a  signal  for  which  success  would  be  likely.  It  was  found,  however,  that  during  subsequent  testing  with  captures  exhibiting  more  challenging 
 multipath  conditions,  some  TVs  would  change  channels  or  even  turn  off  during  the  period  when  no  recognizable  signal  was  received.  Consequently,  it  was  often  necessary  to  return  to  an  easier  capture 
 from  the  same  broadcast  source  at  various  times  during  the  testing  to  ensure  that  the  TVs  were  still  locked  on  to  that  broadcast. 


 PROCEDURES 
 Test  procedures  applicable  to  the  DTV  measurements  conducted  for  this  report  are  shown  below. 
125
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 A-  12 
 EQUIPMENT 
 Table  A-  1  identifies  the  equipment  used  for  the  tests  that  were  conducted  for  this  report. 


 Table  A-  1.  Equipment  List 


 MAKE  MODEL  EQUIPMENT  S/  N  CAL  DATE  USE  Sencore  RFP910  RF  Player  007,  Run  11A  8/  10/  05  ATSC  source  for  all  tests 
 Agilent  89441A  Vector  Signal  Analyzer  US40514809  /US39313048  9/  17/  04  CNR  measurements  before  8/  30/  05; 
 amplitude  of  injected  captures  before  8/  30/  05 
 Agilent  89441A  Vector  Signal  Analyzer  US40514815  /US39313021  8/  8/  05  CNR  measurements  after  8/  30/  05; 
 All  minimum  signal  measurements 
 Agilent  E7405A  Spectrum  Analyzer  US41160406  10/  27/  04  Calibration  of  minimum-loss  impedance-  matching 
 pads  (6/  7/  05)  Agilent  E7405A  Spectrum 
 Analyzer  US41160425  8/  16/  05  Frequency  response  of  splitter  test  configuration  Noise/  Com  UFX-7110  Noise 
 Generator  P292-  0135  **  Noise  source  for  white-noise  threshold  tests 
 Notes:  **  Last  factory  calibration  was  8/  21/  01,  but  for  the  reported  tests,  output  was  calibrated  by 


 means  of  Agilent  E7405A  spectrum  analyzer  at  the  time  of  each  test. 
131
 Federal  Communications  Commission  FCC  05-  199 
 A-  13 
 NOISE  GENERATOR  STEP  ATTEN 
 ATSC  RF  CAPTURE 
 PLAYER 


 50-  75  ohm  min  loss  pad 


 25-  FT  COAX  #5 
 25-  FT  COAX  #1  DTV  Rcvr 
 25-  FT  COAX  #8 
 Ref  Rcvr* 
 50-  ohm  coax  (25-  ft  cables  are  LMR-  400-  UF) 


 50-  75  ohm  min  loss  pad  25-  FT 
 COAX  #9  DTV  Rcvr 


 75-  ohm  BNC  90  elbow  +  BNC  to  F  adapter 


 6-  dB  PAD  3-  dB  PAD 
 STEP  ATTEN  6-  dB  PAD  3-  dB  PAD 
 2-  dB  PAD 


 Direct  connection 
 6-  dB  PAD  VECTOR  SIGNAL 
 ANALYZER 


 6-  dB  PAD 


 MLP#  1 
 MLP#  9 
 Perform  Port  8  cal  both  w/  6-  dB  pad  & 
 w/  min  loss  pad  #4  P#  4 


 P#  5 


 75-  50  ohm  transformer  6-  dB  PAD  A1  A2  6-  dB  PAD 
 A1  =  MiniCircuits  ZFL-  1000H  (28  dB  min  gain;  20  dBm  1-  dB  compr)  A2  =  MiniCircuits  ZFL-  1000VH  (20  dB  min  gain;  25  dBm  1-  dB  compr) 
 Combiner  =  MiniCircuits  ZFDC  10-  2  directional  coupler  (10.75  dB  coupling,  10    1000  MHz)  9-  Way  Splitter  =  4  Minicircuits  ZA3PD-  1  three-  way  power  splitters  (500    1000  MHz);  1  st  splitter  drives  the  remaining  three  splitters 
 Step  Attenuators  =  Alan  Industries  models  50V70  N,  50V10  N,  and  50V1  N  cascaded  to  provide  0  -  81  dB  in  0.1-  dB  steps  LPF  =  Microlab  LP  Filter  FL701  (700  MHz  LPF  resulted  in  output  noise  at  Pt5a  being  3  dB  down  at  750  MHz) 
 Minimum  Loss  Pads  =  Trilithic  ZM-  57  75-  50  ohm  transformer  =  Trilithic  ZMT-  57 
 25-  ft  coax  =  Times  Microwave  LMR-  400-  UF 


 Pt8a 
 Pt5a 


 Pt1 
 Pt9  TT#  1 
 PtB 
 PtC 
 3-  dB  PAD 


 LPF 
 9-  WAY  SPLITTER 


   Port  8  connects  to  a  DTV  (w/  50-  75  ohm 
 minimum  loss  pad)  or  to  reference  receiver 
 (w/  6-  dB,  50-  ohm  pad),  as  shown  below 
   Port  5  dedicated  for  measurements 


 50-  ohm  coax  alternate  connection  for  Reference  Receiver 


 3-  dB  PAD 
 PtA 


 COMBINER 
 NOISE  GENERATOR  STEP  ATTEN 


 ATSC  RF  CAPTURE 
 PLAYER 


 50-  75  ohm  min  loss  pad 


 25-  FT  COAX  #5 
 25-  FT  COAX  #1  DTV  Rcvr 
 25-  FT  COAX  #8 
 Ref  Rcvr* 
 50-  ohm  coax  (25-  ft  cables  are  LMR-  400-  UF) 


 50-  75  ohm  min  loss  pad  25-  FT 
 COAX  #9  DTV  Rcvr 


 75-  ohm  BNC  90  elbow  +  BNC  to  F  adapter 


 6-  dB  PAD  3-  dB  PAD 
 STEP  ATTEN  6-  dB  PAD  3-  dB  PAD 
 2-  dB  PAD 


 Direct  connection 
 6-  dB  PAD  VECTOR  SIGNAL 
 ANALYZER 


 6-  dB  PAD 


 MLP#  1 
 MLP#  9 
 Perform  Port  8  cal  both  w/  6-  dB  pad  & 
 w/  min  loss  pad  #4  P#  4 


 P#  5 


 75-  50  ohm  transformer  6-  dB  PAD  A1  A2  6-  dB  PAD 
 A1  =  MiniCircuits  ZFL-  1000H  (28  dB  min  gain;  20  dBm  1-  dB  compr)  A2  =  MiniCircuits  ZFL-  1000VH  (20  dB  min  gain;  25  dBm  1-  dB  compr) 
 Combiner  =  MiniCircuits  ZFDC  10-  2  directional  coupler  (10.75  dB  coupling,  10    1000  MHz)  9-  Way  Splitter  =  4  Minicircuits  ZA3PD-  1  three-  way  power  splitters  (500    1000  MHz);  1  st  splitter  drives  the  remaining  three  splitters 
 Step  Attenuators  =  Alan  Industries  models  50V70  N,  50V10  N,  and  50V1  N  cascaded  to  provide  0  -  81  dB  in  0.1-  dB  steps  LPF  =  Microlab  LP  Filter  FL701  (700  MHz  LPF  resulted  in  output  noise  at  Pt5a  being  3  dB  down  at  750  MHz) 
 Minimum  Loss  Pads  =  Trilithic  ZM-  57  75-  50  ohm  transformer  =  Trilithic  ZMT-  57 
 25-  ft  coax  =  Times  Microwave  LMR-  400-  UF 


 Pt8a 
 Pt5a 


 Pt1 
 Pt9  TT#  1 
 PtB 
 PtC 
 3-  dB  PAD 


 LPF 
 9-  WAY  SPLITTER 


   Port  8  connects  to  a  DTV  (w/  50-  75  ohm 
 minimum  loss  pad)  or  to  reference  receiver 
 (w/  6-  dB,  50-  ohm  pad),  as  shown  below 
   Port  5  dedicated  for  measurements 


 50-  ohm  coax  alternate  connection  for  Reference  Receiver 


 3-  dB  PAD 
 PtA 


 COMBINER 


 Figure  A-  1.  Block  Diagram  of  Test  Configuration  for  Required  CNR  and  RF  Capture  Tests 
 10-  dB  pad 
 ATSC  RF  CAPTURE 
 PLAYER 
 75-  50  ohm  min  loss  pad 


 VECTOR  SIGNAL 
 ANALYZER 


 50-  75  ohm  min  loss  pad 
 DTV 


 STEP  ATTEN  6-  dB  PAD  3-  dB  PAD 


 10-  dB  pad 


 Also  measure  VSA  noise  floor  on  same  amplitude  range  of  VSA 
 6-  dB  PAD 
 Terminate  any  RF  outputs  on  DTV 


 receivers  w/  75  ohms 


 75-  ohm  BNC  90  elbow  +  BNC  to  F  adapter  #12  #11 
 Pt1 


 PtB  25-  FT  COAX 


 50-  ohm  coax  (25-  ft  cables  are  LMR-  400UF) 
 Direct  connection 


 50-  ohm  coax  as  connected  during  measurement 


 PtA 
 10-  dB  pad 
 ATSC  RF  CAPTURE 
 PLAYER 
 75-  50  ohm  min  loss  pad 


 VECTOR  SIGNAL 
 ANALYZER 


 50-  75  ohm  min  loss  pad 
 DTV 


 STEP  ATTEN  6-  dB  PAD  3-  dB  PAD 


 10-  dB  pad 


 Also  measure  VSA  noise  floor  on  same  amplitude  range  of  VSA 
 6-  dB  PAD 
 Terminate  any  RF  outputs  on  DTV 


 receivers  w/  75  ohms 


 75-  ohm  BNC  90  elbow  +  BNC  to  F  adapter  #12  #11 
 Pt1 


 PtB  25-  FT  COAX 


 50-  ohm  coax  (25-  ft  cables  are  LMR-  400UF) 
 Direct  connection 


 50-  ohm  coax  as  connected  during  measurement 


 PtA 


 Figure  A-  2.  Block  Diagram  of  Test  Configuration  for  Minimum  Signal  at  TOV 
132
 Federal  Communications  Commission  FCC  05-  199 
 A-  14 
 -1.0 
 -0.8 
 -0.6 
 -0.4 
 -0.2 
 0.0 
 0.2 
 0.4 
 0.6 
 0.8 
 1.0 


 563  566  569  572  575 
 Frequency  (MHz) 


 Signal 
 Path 
 Power 


 Gain 
 (dB) 


 Pt1  (75  ohms) 
 Pt2  (75  ohms) 
 Pt3  (75  ohms) 
 Pt4  (75  ohms) 
 Pt6  (75  ohms) 
 Pt7  (75  ohms) 
 Pt8  (75  ohms) 
 Pt9  (75  ohms) 
 Pt8a  (50  ohms) 
 Pt5a  (50  ohms) 


 CHANNEL  30 


 Figure  A-  3.  Frequency  Response  of  Each  Port 


 -1.0 
 -0.8 
 -0.6 
 -0.4 
 -0.2 
 0.0 
 0.2 
 0.4 
 0.6 
 0.8 
 1.0 


 563  566  569  572  575 
 Frequency  (MHz) 


 Signal 
 Path 
 Power 


 Gain 
 (dB) 


 Other  ports  terminated  in  75  ohms 
 Other  ports  connected  to  TVs  tuned  to  chan  30 
 Other  ports  open 


 CHANNEL  30 


 Figure  A-  4.  Effect  of  Load  Impedance  Mismatch 
133
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 A-  15 
 SPECTRUM  ANALYZER 
 Tracking  Generator  Output 


 Include  only  for  measurements  at  75-  ohm  points 
 10-  dB  PAD  Injection  Point 
 Input 
 75-  50  ohm  transformer 


 TT#  1 
 Measurement  Point 
 Test  Setup  Calibration 
 SPECTRUM  ANALYZER 


 Tracking  Generator  Output 


 Include  only  for  measurements  at  75-  ohm  points 
 10-  dB  PAD  Injection  Point 
 Input 
 75-  50  ohm  transformer 


 TT#  1 
 Measurement  Point 
 Test  Setup  Calibration 


 Figure  A-  5.  Calibration  Connection  for  Test  Setup  for  Required  CNR  and  RF  Capture  Tests 


 -120 
 -110 
 -100 
 -90 
 -80 
 -70 


 565  566  567  568  569  570  571  572  573 
 Frequency  (MHz) 


 Spectrum 


 Level 
 (dBm 
 in 
 30 


 kHz 


 resolution 


 bandwidth) 


 Injected  Signal 
 Injected  Noise 
 Spectrum  Analyzer  Noise 


 CHANNEL  30 


 Figure  A-  6.  Spectra  of  Injected  Signal  and  Noise  at  15-  dB  CNR 
134
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 B-  1 
 APPENDIX  B:  SUMMARY  OF  RF  FIELD  CAPTURES 
 Table  B-  1  lists  the  50  ATSC-  recommended  captures,  some  of  their  characteristics,  and  the  number  of  consumer  DTV  receivers  (of  28)  that  successfully  demodulated  each  capture  in  tests  for  this  report. 
 The  three  captures  having  no  video  content  (e.  g.,  grey  or  black  screens)  were  not  tested,  except  with  an  instrumented  receiver  which  is  not  included  in  the  tabulated  results.  In  counting  observed  video  errors, 
 errors  coinciding  with  the  locations  of  known  symbol  drops,  as  reported  by  the  ATSC,  were  not  counted.  Note  that  four  of  the  captures  on  which  no  tested  receiver  achieved  demodulation  free  of  visual  errors 
 were  identified  by  the  ATSC  as  having  possible  non-  linearities  caused  by  high-  level  adjacent  channels  overdriving  the  recording  system. 


 Notes  on  Table  B-  1  (next  page):  All  captures  have  durations  of  23  or  25  seconds 
 *  Site:  HR  =  high  rise  apartment;  SF  =  single  family  home;  TH  =  townhouse  Antenna:  ID  =  indoors  at  6-  ft  height;  OD  =  outdoors  at  30-  ft  height 
 **  Issues:  DS  =  48  dropped  symbols  at  specified  location;  NL  =  recording  may  contain  nonlinearities  due  to  strong  adjacent  channel 
135
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 D-  1 
 APPENDIX  D 
 NOTICE  OF  INQUIRY 
137
 Federal  Communications  Commission  FCC  05-  94 
 Before  the  Federal  Communications  Commission 
 Washington,  D.  C.  20554 


 In  the  Matter  of 
 Technical  Standards  for  Determining  Eligibility  For  Satellite-  Delivered  Network  Signals  Pursuant 
 To  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act 


 )  ) 
 )  ) 
 )  ET  Docket  No.  05-  182 


 NOTICE  OF  INQUIRY 
 Adopted:  April  29,  2005  Released:  May  3,  2005 
 Comment  Date:  30  Days  after  Publication  in  the  Federal  Register  Reply  Comment  Date:  45  Days  after  Publication  in  the  Federal  Register 


 By  the  Commission: 
 1.  By  this  action,  the  Commission  begins  an  inquiry  into  the  adequacy  of  the  digital  signal  strength  standard  and  testing  procedures  used  to  determine  whether  households  are  eligible  to  receive  distant 
 broadcast  digital  television  (DTV)  network  signals  from  satellite  communications  providers.  We  request  comment  and  information  on  whether  the  existing  statutes  and/  or  regulations  concerning  the  digital 
 television  signal  strength  standard  and  testing  procedures  as  used  for  identifying  if  households  are  unserved  by  local  network  TV  signals  for  purposes  of  determining  eligibility  to  receive  distant  signals 
 from  satellite  services  need  to  be  revised.  We  specifically  intend  to  study  whether  such  statutes  and  regulations  should  be  revised  to  take  into  account  the  types  of  antennas  that  are  available  to  consumers. 
 The  record  obtained  through  this  inquiry  will  be  used  to  prepare  a  report  to  Congress  describing  the  results  of  this  study  and  the  Commissions  recommendations,  if  any,  for  changes  that  should  be  made  to 
 the  applicable  Federal  statutes  or  regulations.  In  this  proceeding,  we  are  not  considering  alteration  of  the  DTV  signal  strength  standard  for  any  purpose  other  than  determining  household  eligibility  to  receive 
 retransmitted  distant  network  signals.  We  are  initiating  this  inquiry  in  response  to  provisions  of  Section  204(  b)  of  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004  (SHVERA).  310 


 BACKGROUND 
 2.  Broadcast  television  stations  have  rights,  through  the  Copyright  Act  311  and  private  contracts,  to  control  the  distribution  of  the  national  and  local  programming  that  they  transmit.  312  In  1988,  Congress 
 adopted  the  Satellite  Home  Viewer  Act  (SHVA)  as  an  amendment  to  the  Copyright  Act  in  order  to  protect 


 310  The  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004,  Pub.  L.  No.  108-  447,    207,  118  Stat 
 2809,  3393  (2004)  (to  be  codified  at  47  U.  S.  C.    325),    204(  b).  The  SHVERA  was  enacted  as  title  IX  of  the  Consolidated  Appropriations  Act,  2005. 


 311  17  U.  S.  C.    119.  The  Satellite  Home  Viewer  Act  is  part  of  this  copyright  statute. 
 312  Satellite  Delivery  of  Network  Signals  to  Unserved  Households  for  Purposes  of  the  Satellite  Home  Viewer  Act, 
 CS  Docket  No.  98-  201,  Report  and  Order,  14  FCC  Rcd  2654  at    2  (1999)  (SHVA  Report  and  Order). 
138
 Federal  Communications  Commission  FCC  05-  94 
 2 
 the  broadcasters'  interests  in  their  programming  while  simultaneously  enabling  satellite  communications  providers  to  provide  broadcast  programming  to  those  satellite  subscribers  who  are  unable  to  obtain 
 broadcast  TV  network  programming  over  the  air.  313  Under  the  SHVA,  those  subscribers  were  generally  considered  to  be  "unserved"  by  local  stations.  Pursuant  to  the  requirements  of  this  statute,  which  linked 
 the  definition  of  unserved  households  to  a  Commission-  defined  measure  of  analog  television  signal  strength  known  as  Grade  B  intensity,  314  the  Commission  adopted  rules  for  determining  whether  a 
 household  is  able  to  receive  a  television  signal  of  this  strength.  315  In  particular,  the  Commission  adopted  rules  established  a  standardized  method  for  measuring  the  strength  of  television  signals  at  individual 
 locations  and  endorsed  a  method  for  predicting  the  strength  of  such  signals  that  could  be  used  in  place  of  actually  taking  measurements.  316  For  DTV  stations,  the  counterparts  to  the  Grade  B  signal  intensity 
 standards  for  analog  television  stations  are  the  values  set  forth  in  Section  73.622(  e)  of  the  Commissions  rules  describing  the  DTV  noise-  limited  service  contour.  317 


 3.  In  the  Satellite  Home  Viewer  Improvement  Act  of  1999  (SHVIA),  318  Congress  revised  and  extended  the  statutory  provisions  established  by  the  1988  SHVA.  With  regard  to  prediction  of  signal 
 availability,  the  SHVIA  added  Section  339(  c)(  3)  to  the  Communications  Act  of  1934,  as  amended  (47  U.  S.  C.    339(  c)(  3)),  which  provides  that  [  T]  he  Commission  shall  take  all  actions  necessary,  including 
 any  reconsideration,  to  develop  and  prescribe  by  rule  a  point-  to-  point  predictive  model  for  reliably  and  presumptively  determining  the  ability  of  individual  locations  to  receive  signals  in  accordance  with  the 
 signal  intensity  standard  in  effect  under  Section  119(  d)(  10)(  A)  of  title  17,  United  States  Code.  319  Section  339(  c)(  3)  further  provides  that  [  I]  n  prescribing  such  a  model,  the  Commission  shall  rely  on  the 
 Individual  Location  Longley-  Rice  model  set  forth  by  the  Federal  Communications  Commission  in  Docket  No.  98-  201,  and  ensure  that  such  model  takes  into  account  terrain,  building  structures,  and  other  land 
 cover  variations.  The  Commission  shall  establish  procedures  for  the  continued  refinement  in  the  application  of  the  model  by  the  use  of  additional  data  as  it  becomes  available.  320  The  Individual 


 313  17  U.  S.  C.    119,  122  (Copyright  Act  provisions);  47  U.  S.  C.    325,  338,  339  (Communications  Act 
 provisions). 
 314  See  17  U.  S.  C.    119(  d)(  10)(  A);  see  also  47  CFR    73.  683(  a).  Section  119(  d)(  10)  (A)  of  the  Copyright  Act 
 defines  an  unserved  household  as  a  household  that  cannot  receive,  through  use  of  a  conventional  stationary,  outdoor  rooftop  receiving  antenna,  an  over-  the-  air  signal  of  a  primary  network  television  station  affiliated  with 


 that  network  of  Grade  B  intensity  as  defined  by  the  Federal  Communications  Commission  under  section  73.  683(  a)  of  title  47  of  the  Code  of  Federal  Regulations,  as  in  effect  on  January  1,  1999.  Section  73.  683(  a)  sets  forth  field 
 strength  levels  for  the  Grade  B  coverage  contours  of  analog  TV  stations  as  follows,  units  are  one  micro-  volt  per  meter  (dB):  channels  2-  6  47  dB,  channels  7-  13  56  dB,  channels  14-  69  64  dB. 


 315  SHVA  Report  and  Order,  14  FCC  Rcd  2654  at    4. 
 316  Id.  at    71.  The  Individual  Location  Longley-  Rice  (ILLR)  predictive  model  is  used  to  predict  the  Grade  B 
 signal  intensity  at  a  location.  47  CFR  Section  73.  686(  d)  specifies  the  measurement  procedure  used  to  obtain  the  signal  intensity  at  an  individual  location. 


 317  47  CFR    73.  622(  e).  See  also  47  CFR    73.  625(  b)  (determining  coverage). 
 318  The  Satellite  Home  Viewer  Improvement  Act  of  1999,  Pub.  L.  No  106-  113,  113  Stat.  1501  (1999)  (codified  in 
 scattered  sections  of  17  and  47  U.  S.  C.).  The  SHVIA  was  enacted  on  November  29,  1999,  as  Title  I  of  the  Intellectual  Property  and  Communications  Omnibus  Reform  Act  of  1999  (IPACORA)  (relating  to  copyright 


 licensing  and  carriage  of  broadcast  signals  by  satellite  carriers). 
 319  See  SHVIA,  section  1008. 


 320  See  Satellite  Delivery  of  Network  Signals  to  Unserved  Households  for  Purposes  of  the  Satellite  Home  Viewer 
 Act;  Part  73  Definition  and  Measurement  of  Signals  of  Grade  B  Intensity,  Report  and  Order,  CS  Docket  No.,  98-201,  14  FCC  Rcd  2654  (1999).  A  computer  is  needed  to  make  these  predictions  because  of  the  large  number  of 


 reception  points  that  must  be  individually  examined.  Computer  code  for  the  ILLR  point-  to-  point  radio  propagation  model  is  published  in  an  appendix  of  NTIA  Report  82-  100,  A  Guide  to  the  Use  of  the  ITS  Irregular 
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 Location  Longley-  Rice  (ILLR)  radio  propagation  model  adopted  by  the  Commission  in  CS  Docket  No.  98-  201  provides  predictions  of  radio  field  strength  at  specific  geographic  points  based  on  the  elevation 
 profile  of  terrain  between  the  transmitter  and  each  specific  reception  point.  321  The  SHVIA  further  required  that  the  courts  rely  on  the  Individual  Location  Longley-  Rice  (ILLR)  model  established  by  the 
 Commission  for  making  presumptive  determinations  of  whether  a  household  is  capable  of  receiving  broadcast  television  signals  of  at  least  a  certain  threshold  intensity. 


 4.  As  indicated  above,  the  threshold  signal  intensity  level  for  determining  eligibility  to  receive  retransmitted  distant  analog  network  TV  signals  is  the  Grade  B  standard  set  forth  in  Section  73.683(  a)  of 
 the  Commissions  rules.  The  Grade  B  contour,  originally  established  to  describe  the  service  area  (or  coverage  contour)  of  analog  TV  stations,  defines  a  geographic  boundary  curve  on  which  the  specified 
 field  strength  is  predicted  to  be  exceeded  50  percent  of  the  time  at  50  percent  of  the  locations.  322  However,  the  values  of  the  Grade  B  standard  are  set  such  that  generally,  if  a  household  receives  a 
 television  signal  of  Grade  B  intensity,  it  should  receive  an  acceptable  television  picture  at  least  90  percent  of  the  time.  More  specifically,  the  Grade  B  values  represent  field  strengths  that  are  strong  enough,  in  the 
 absence  of  man-  made  noise  or  interference  from  other  stations,  to  provide  at  least  90  percent  of  the  time  a  television  picture  that  the  mean  observer  would  classify  as  acceptable  using  a  receiving  installation 
 (antenna,  transmission  line,  and  receiver)  typical  of  outlying  or  near-  fringe  areas.  323 
 5.  The  SHVIA  directed  the  Commission  to  evaluate  all  possible  standards  and  factors  for  determining  eligibility  for  retransmission  of  signals  of  network  stations  to  determine  whether  it  may  be 


 appropriate  to  recommend,  in  a  report  to  Congress,  modifying  or  replacing  the  Grade  B  intensity  standard  for  the  purpose  of  determining  eligibility,  and,  if  appropriate,  to  make  a  further  recommendation  relating 
 to  a  standard  for  digital  signals.  324  In  November  2000,  the  Commission  issued  its  Report  to  Congress  in  this  matter,  325  recommending  that  the  Grade  B  signal  intensity  standard  and  eight  of  the  nine  planning 


 Terrain  Model  in  the  Area  Prediction  Mode,  authors  G.  A.  Hufford,  A.  G.  Longley  and  W.  A.  Kissick,  U.  S.  Department  of  Commerce,  April  1982.  Some  modifications  to  the  code  were  described  by  G.  A.  Hufford  in  a 
 memorandum  to  users  of  the  model  dated  January  30,  1985.  With  these  modifications,  the  code  is  referred  to  as  Version  1.2.2  of  the  Longley-  Rice  model. 


 321  Id.  at  69. 
 322  See  47  C.  F.  R.  73.  683  (a),  and  47  C.  F.  R.  73.  684  (c). 
 323  The  Grade  B  signal  contour  describes  a  boundary  around  a  television  stations  transmitter.  As  set  forth  in 
 Section  73.  683(  a),  a  signal  of  Grade  B  intensity  is  defined  as  a  discrete  value  measured  in  units  of  dBv/  m  (dB  over  a  microvolt  per  meter).  However,  the  absolute  intensity  of  broadcast  signals  at  particular  locations  and  at 


 particular  times  cannot  be  precisely  determined  through  predictive  means,  regardless  of  the  predictive  method  used.  Signal  strength  varies  randomly  over  location  and  time,  so  signal  propagation  must  be  considered  on  a 
 statistical  basis.  This  is  true  regardless  of  whether  the  signal  intensity  is  predicted  at  a  fixed  location  (such  as  an  individual  household)  or  over  an  area.  Some  prediction  methods,  including  the  Commissions  field  strength  charts 
 (propagation  curves),  predict  the  occurrence  of  median  signal  strengths  (i.  e.,  signal  strengths  predicted  to  be  exceeded  at  50%  of  the  locations  in  a  particular  area  at  least  50  percent  of  the  time).  Using  these  methods, 
 location  and  time  variability  factors  are  added  to  the  signal  level  for  an  acceptable  picture  so  that  the  desired  statistical  reliability,  i.  e.,  50  percent  of  locations  90  percent  of  the  time,  is  achieved.  The  values  chosen  for  the 
 Grade  B  signal  intensity  standards  account  for  this  variability  and,  therefore,  as  indicated  above,  predict  that  at  least  50  percent  of  the  locations  along  the  Grade  B  contour  will  receive  an  acceptable  picture  90  percent  of  the 
 time.  For  additional  information  on  Grade  B  contours,  see  Understanding  Televisions  Grade  A  and  Grade  B  Service  Contours. 


 324  See  section  339(  c)(  1)  of  the  Communications  Act  of  1934,  as  amended  by  the  SHVIA,  section  1008. 
 325  See  Technical  Standards  for  Determining  Eligibility  for  Satellite-  Delivered  Network  Signals  Pursuant  to  the 
 Satellite  Home  Viewer  Improvement  Act,  Report,  ET  Docket  No.  00-  90,  FCC  00-  416  (2000);  see  also  id.,  Notice  of  Inquiry,  FCC  00-  184,  released  May  26,  2000. 
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 factors  326  used  in  that  model  be  retained  as  the  basis  for  predicting  whether  a  household  is  eligible  to  receive  retransmitted  distant  TV  network  signals  under  SHVIA.  The  Commission  also  recommended 
 modification  of  the  remaining  planning  factor,  i.  e.,  time  fading,  by  replacing  its  existing  fixed  values  with  location-  dependent  values  determined  for  the  actual  receiving  locations  using  the  ILLR  prediction  model. 
 Finally,  the  Commission  found  that  it  would  be  premature  to  construct  a  distant  network  signal  eligibility  standard  for  DTV  signals  at  that  time.  Therefore,  the  Commission  recommended  that  establishment  of  a 
 distant  network  signal  eligibility  standard  for  DTV  signals  be  deferred  until  such  time  as  more  substantial  DTV  penetration  is  achieved  and  more  experience  is  gained  with  DTV  operation. 


 6.  The  Commission  has  established  a  DTV  Table  of  Allotments,  which  specifies  channels  for  use  by  DTV  stations  in  individual  communities,  using  a  procedure  that  closely  replicates  the  service  areas  of  the 
 existing  Grade  B  contours  for  analog  TV  stations.  327  In  particular,  the  Commission  has  defined  DTV  station  service  areas  based  on  field  strength  levels  that  provide  noise-  limited  service  (the  Grade  B  signal 
 strength  levels  define  noise-  limited  service  for  analog  stations).  328  DTV  service  areas  are  defined  as  the  geographic  area  within  a  stations  noise-  limited  field  strength  contour  where  its  signal  strength  is 
 expected  to  exceed  that  field  strength  level  at  50  percent  of  the  locations  90  percent  of  the  time  F(  50,90).  329  Within  that  contour,  service  is  considered  available  at  locations  where  a  stations  signal 
 strength,  as  predicted  using  the  terrain  dependent  Longley-  Rice  point-  to-  point  propagation  model,  exceeds  the  noise-  limited  standards.  The  DTV  noise-  limited  field  strength  standards  are:  channels  2-  6 
 (low  VHF)-  28  dB,  channels  7-  13  (high  VHF)-  36  dB,  channels  14-  69  (UHF)-  41  dB.  These  criteria  presume  that  households  will  exert  similar  efforts  to  receive  DTV  broadcast  stations  as  they  have  always 
 been  expected  to  exert  to  receive  NTSC  analog  TV  signals. 
 7.  In  December  2004,  Congress  enacted  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004,  330  which  again  amends  the  copyright  laws  331  and  the  Communications  Act  332  to  further  aid 


 the  competitiveness  of  satellite  carriers  and  expand  program  offerings  for  satellite  subscribers.  Section  204  of  the  SHVERA  provides  that  no  later  than  one  year  after  the  date  of  enactment  of  this  Act,  the 
 Commission  is  to  complete  an  inquiry  regarding  whether,  for  purposes  of  identifying  if  a  household  is  unserved  by  an  adequate  digital  signal  under  Section  119(  d)(  10)  of  title  17  of  the  United  States  Code,  the 
 digital  signal  strength  standard  in  Section  73.622(  e)(  1)  of  the  Commission  rules  or  the  testing  procedures  in  Section  73.686(  d)  of  those  rules  should  be  revised  to  take  into  account  the  types  of  antennas  that  are 
 available  to  consumers.  333  Section  204  of  the  SHVERA  also  requires  the  Commission  to  submit  to  the 
 326  The  eight  planning  factors  that  the  Commission  recommended  should  be  unchanged  were  the:  Thermal  Noise 
 Factor;  Receiver  Noise  Figure;  Signal-  to-  Noise  Ratio  and  Service  Quality;  Transmission  Line  Loss;  Receiving  Antenna  Gain;  Dipole  Factor;  Terrain  Variability;  and  Environmental  Noise. 


 327  The  DTV  Table  of  Allotments  is  set  forth  in  Section  73.  622(  b)  of  the  rules,  47  C.  F.  R.    73.  622(  b). 
 328  Noise-  limited  service  means  that  reception  of  service  at  the  described  signal  level  is  only  limited  by  the 
 presence  of  radiofrequency  noise  that  is  expected  to  be  present  at  the  same  level  as  the  desired  signal. 
 329  See  47  C.  F.  R.    73.  622  (e)(  1)  and  (2).  The  F(  50,  90)  level  of  service  was  established  for  DTV  service  areas  to 
 account  for  the  fact  that  DTV  service  is  subject  to  a  cliff  effect  by  which  full  quality  service  becomes  totally  unavailable  within  a  very  small  decrease  in  signal  strength  whereas  analog  TV  service  quality  degrades  gradually 


 with  declining  signal  strength.  The  distance  to  field  strength  contours  with  service  at  the  F(  50,  90)  levels  of  service  is  determined  using  the  charts  in  Section  73.  699  of  the  rules,  47  C.  F.  R.    73.  699. 


 330  See  SHVERA,  supra  note  1. 
 331  Section  102  of  the  SHVERA  creates  a  new  17  U.  S.  C.    119(  a)(  3)  to  provide  satellite  carriers  with  a  statutory 
 copyright  license  to  offer  significantly  viewed  signals  as  part  of  their  local  service  to  subscribers.  17  U.  S.  C.    119(  a)(  3). 


 332  See  47  U.  S.  C.    325,  338,  339  and  340. 
 333  See  17  U.  S.  C.    119(  d)(  10);  47  C.  F.  R.    73.  622(  e)(  1);  47  C.  F.  R.    73.  686(  d). 
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 antenna  than  will  an  indoor  antenna  installation.  Thus,  households  in  which  the  antenna  is  placed  indoors  will  generally  need  an  antenna  with  greater  gain  than  will  a  household  in  which  the  antenna  is  placed 
 outdoors. 
 10.  As  indicated  above,  the  Commission  defines  digital  television  service  areas  on  the  basis  of  stations  noise-  limited  F(  50,  90)  contour.  Within  this  contour,  the  Longley-  Rice  model  is  used  to  predict 


 areas  where  the  DTV  signal  strength  level  exceeds  the  noise  limited  service  level.  335  Inherent  in  this  method  of  predicting  received  signal  strength  levels  are  certain  assumptions  regarding  the  receiving 
 system.  For  DTV,  the  Commission  assumes  that  the  receiving  antenna  is  located  outdoors  at  a  height  of  10  meters  above  ground.  336  In  addition,  the  Commissions  procedures  for  evaluating  DTV  service  areas 
 set  forth  specific  values  for  antenna  gain  that  depend  upon  the  specific  DTV  channel  band,  namely,  4  dB  for  low  VHF,  6  dB  for  high  VHF,  and  10  dB  for  UHF  and  that  the  antenna  be  oriented  in  the  direction 
 which  maximizes  the  values  for  field  strength  for  the  signal  being  measured.  337 
 11.  With  regard  to  the  general  characterization  of  antennas  described  above,  we  seek  comment  on  whether  there  is  a  need  to  revise  the  standard  by  which  adequate  DTV  network  signals  are  deemed 


 available  to  households  in  order  to  account  for  the  facts  that  DTV  antennas  can  be  mounted  on  a  roof  or  within  a  home  and  can  be  installed  in  a  fixed  position  or  in  a  mounting  that  allows  them  to  be  rotated. 
 Specifically,  we  ask  if  the  inherent  assumptions  regarding  DTV  antenna  receiving  systems  should  be  modified  or  extended  insofar  as  they  relate  to  the  proper  determination  of  whether  households  are 
 unserved  by  adequate  broadcast  DTV  network  signals  and  are  thus  eligible  to  receive  distant  DTV  network  signals  from  a  satellite  service  provider.  To  properly  evaluate  this  issue,  we  must  have  up-  to-date 
 reliable  information  regarding  antennas  that  are  available  to  the  public.  Therefore,  commenting  parties  are  requested  to  provide  information  on  the  types  of  antennas  that  are  in  use  currently,  or  soon  to 
 be  available  for  outdoor  or  indoor  residential  use.  For  these  antennas,  we  request  that  relevant  technical  specifications  such  as  size,  gain,  and  beamwidth  be  provided.  In  addition,  we  request  that  commenting 
 parties  provide  information  on  how  these  factors  affect  antenna  cost  and  deployment.  Further,  we  request  information  on  the  availability  and  cost  of  various  devices  that  can  be  used  to  aim  these  antennas  (e.  g., 
 rotors)  toward  DTV  transmitters.  In  this  regard,  we  request  comment  on  how  the  addition  of  a  rotor  would  affect  the  antenna  size  and  thus  the  ability  of  consumers  to  mount  the  antenna  indoors.  We  ask  that 
 commenters  provide  an  evaluation  of  whether  the  use  of  an  indoor  antenna  with  or  without  a  rotor  would  provide  similar  performance  to  that  expected  based  on  the  Commissions  assumed  planning  factors.  If 
 commenting  parties  believe  that  performance  would  differ  significantly,  we  request  that  they  provide  detailed  analytical  information  and  explain  how  they  believe  our  procedures  should  be  modified. 


 12.  Signal  strength  measurement.  Congress  has  requested  that  the  Commission  consider  whether  Section  73.686(  d)  of  the  rules  should  be  amended  to  specify  procedures  for  determining  if  the  requisite 
 digital  signal  strength  is  present  that  are  different  from  the  procedures  used  for  determining  analog  signal  strength.  Currently,  Section  73.686(  d)  requires  that  field  strength  measurements  be  made  using  either  a 
 half  wave  dipole  antenna  that  is  tuned  to  the  stations  visual  carrier  frequency  or  a  gain  antenna,  provided  that  the  antenna  factor  for  the  channel  under  test  is  known.  338  In  addition,  the  rules  specify  that  the 
 intermediate  frequency  (i.  f.)  bandwidth  of  the  measuring  instrumentation  be  at  least  200  kilohertz  but  no  more  than  1,000  kilohertz.  Measurements  are  to  be  taken  in  five  locations,  preferably  close  to  the  actual 
 antenna  or  where  one  is  likely  to  be  mounted.  In  addition,  the  rules  specify  that  the  measurement  antenna  is  to  be  raised  to  a  height  of  6.1  meters  (20  feet)  above  ground  for  one  story  structures  and  9.1  meters  (30 
 feet)  above  ground  for  two  story  or  taller  structures.  Finally,  because  the  current  rule  was  written  specifically  to  determine  the  field  strength  of  analog  TV  signals,  the  procedures  specify  that  the  field 


 335  See  47  C.  F.  R.    73.  622(  e). 
 336  See  OET  Bulletin  69,  Longley-  Rice  Methodology  for  Evaluating  TV  Coverage  and  Interference. 
 337  Id. 
 338  See  47  CFR  73.  686(  d). 
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 strength  measurement  is  to  be  made  on  the  visual  carrier.  339  The  measured  values  can  then  be  compared  to  the  field  strength  that  defines  the  Grade  B  contour  for  the  station  in  question  to  determine  if  the 
 measured  location  is  receiving  a  signal  of  sufficient  intensity  for  analog  television  reception. 
 13.  It  is  readily  apparent  that  Section  73.  686(  d)  needs  some  modification  in  order  to  be  applied  to  digital  TV  signals.  Unlike  the  analog  signal,  the  digital  signal  does  not  contain  a  visual  carrier. 


 Therefore,  at  a  minimum  the  rule  must  distinguish  between  analog  and  digital  signals  as  it  relates  to  the  specific  frequency  on  which  to  tune.  We  note  that  the  digital  TV  signal  does  have  a  pilot  signal  that  is 
 used  by  the  tuner  to  lock  in  on  the  desired  received  signal.  340  Given  this  fundamental  difference  between  the  analog  and  digital  signal,  we  ask  commenting  parties  to  provide  information  on  the  signal 
 characteristics  to  which  the  measurement  instrumentation  should  be  tuned.  For  example,  we  believe  that  it  makes  most  sense  to  tune  the  instrumentation  either  to  the  pilot  signal  or  to  the  center  of  the  channel. 
 We  also  ask  for  comments  on  whether  the  i.  f.  bandwidth  of  the  measurement  equipment  that  is  specified  for  analog  TV  signals  is  also  appropriate  for  digital  TV  signals.  Commenting  parties  who  propose  i.  f. 
 bandwidths  that  differ  from  the  current  specification  should  provide  specific  reasons  for  their  proposals.  We  also  request  comment  on  the  height  that  should  be  specified  for  the  use  of  antenna  equipment  to 
 measure  outdoor  signals,  and  on  whether  specific  procedures  should  be  created  for  measuring  indoor  signals.  Further,  if  an  indoor  measurement  procedure  were  adopted  for  determining  signal  availability, 
 we  seek  comment  on  what  criteria  should  be  applied  to  determine  whether  an  indoor  or  an  outdoor  measurement  would  be  performed  at  a  specific  location.  Finally,  we  seek  comment  on  whether  any  other 
 aspects  of  our  measurement  procedures  need  to  be  modified  for  the  purpose  of  determining  if  households  are  unserved  by  an  adequate  digital  TV  signal.  Commenting  parties  should  provide  specific  technical 
 justification  for  any  aspects  that  they  believe  should  be  modified. 
 14.  Signal  strength  standard.  Currently,  the  rules  specify  that  the  field  strength  of  the  Grade  B  contour  of  an  analog  TV  station  be  used  as  the  standard  for  a  determination  of  adequate  signal  strength. 


 In  the  SHVERA,  Congress  requests  that  that  Commission  consider,  for  digital  TV  signals,  whether  a  standard  other  than  the  presence  of  a  signal  of  certain  strength  be  used  to  ensure  that  a  household  can 
 receive  a  high-  quality  picture  using  antennas  of  reasonable  cost  and  ease  of  installation.  We  request  comment  on  whether  the  current  signal  strength  standard  for  noise-  limited  service  should  be  used  to 
 define  the  availability  of  a  DTV  signal  for  determining  whether  a  household  is  eligible  to  receive  distant  DTV  signals  from  DBS  services.  In  this  connection,  we  also  seek  comment  on  whether  there  is  a 
 standard  other  than  one  based  on  signal  strength  that  could  be  used  to  determine  if  a  household  is  capable  of  receiving  a  high-  quality  digital  TV  picture.  Commenting  parties  who  propose  a  standard  not  based  on 
 signal  strength  should  provide  sufficient  detail  describing  how  their  method  would  ensure  reception  of  service  and  should  explain  how  the  proposed  standard  would  be  affected  by  the  various  technical 
 characteristics  the  various  specific  antennas  that  are  available  or  will  soon  be  available  for  the  residential  market. 


 15.  Development  of  a  predictive  model.  The  SHVERA  requires  that  the  Commission  consider  whether  to  develop  a  predictive  methodology  for  determining  whether  a  household  is  unserved  by  an 
 adequate  digital  TV  network  signal  under  section  119(  d)(  10)  of  title  17,  United  States  Code.  341  As 


 339  See  47  C.  F.  R.    73.  686(  d)(  1)(  i)  and  73.  686(  d)(  2)(  i). 
 340  The  pilot  signal  is  located  0.  31  MHz  inside  the  lower  band  edge  of  the  spectrum  and  is  3  dB  lower  than  the 
 average  power  of  the  signal. 
 341  17  U.  S.  C.    119(  d)(  10)  provides  the  following  definition  of  unserved  household: 


 (10)  Unserved  household.  The  term  unserved  household,  with  respect  to  a  particular  television  network,  means  a  household  that 
 (A)  cannot  receive,  through  the  use  of  a  conventional,  stationary,  outdoor  rooftop  receiving  antenna,  an  over-  the-  air  signal  of  a  primary  network  station 
 affiliated  with  that  network  of  Grade  B  intensity  as  defined  by  the  Federal  Communications  Commission  under  section  73.  683(  a)  of  title  47  of  the  Code  of 
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 The  Commission  requests  comment  on  whether  the  modified  Longley-  Rice,  with  appropriate  modifications,  would  accurately  predict  digital  signal  coverage  at  a  specific  location,  or  whether  there  is 
 some  other  predictive  model  that  would  be  more  appropriate  for  this  purpose.  Commenting  parties  who  propose  either  specific  modifications  to  the  modified  Longley-  Rice  or  alternative  models  should  provide 
 detailed  analysis  as  to  how  their  proposed  modifications  will  improve  the  modified  Longley-  Rices  prediction  characteristics  and/  or  an  explanation  of  how  the  changes  or  alternatives  more  accurately  model 
 the  available  signal  level  when  accounting  for  terrain  and  possible  signal  interference. 
 16.  DTV  receiver  threshold  variation.  We  request  comment  on  whether  there  is  a  wide  variation  in  the  ability  of  reasonably  priced  consumer  digital  television  sets  to  receive  over-  the-  air  signals,  so  that  at 
 given  signal  strengths  some  sets  are  able  to  display  high-  quality  pictures  while  other  sets  cannot,  and  if  so,  whether  this  variation  is  related  to  the  price  of  the  television  set.  We  also  request  comment  on 
 whether  such  variation  should  be  factored  into  setting  a  standard  for  determining  whether  a  household  is  unserved  by  an  adequate  DTV  network  signal.  We  are  aware  that  there  are  a  wide  variety  of  digital  TV 
 sets  available  to  consumers  which  are  offered  at  various  prices.  We  do  not  know,  however,  whether  the  difference  in  prices  correlates  to  better  receiver  performance.  We  further  note  that  many  satellite 
 reception  set-  top-  boxes  also  contain  DTV  tuners,  and  seek  comment  on  their  reception  capabilities.  In  the  Memorandum  Opinion  and  Order  on  Reconsideration  of  the  Sixth  Report  and  Order,  the  Commission 
 noted  that  receiver  performance  involves  trade-  offs  among  many  factors  and  that  equipment  manufacturers  were  in  the  best  position  to  determine  how  best  to  meet  consumer  demand.  346  We  also 
 noted  that  we  would  continue  to  monitor  DTV  receiver  development,  in  particular  with  regard  to  indoor  reception  and  multi-  path  signal  rejection  performance.  347  On  this  point,  we  plan  to  conduct  measurements 
 on  a  variety  of  digital  TV  sets  and  factor  the  results  of  those  measurements  into  the  report  that  we  will  present  to  Congress  as  required  by  the  SHVERA. 


 17.  We  seek  information  regarding  the  performance  of  digital  receivers.  Specifically,  commenting  parties  should  provide  information  regarding  the  sensitivity  of  various  receivers  and  their  interference 
 rejection  capability  and  should  point  out  if  there  are  different  receiver  signal  processing  algorithms  for  interpreting  digital  TV  signals  and  their  level  of  sophistication.  This  technical  information  should  be 
 accompanied  by  price  data  and  analysis  regarding  the  correlation  between  performance  and  price.  Given  that  the  Commission  intends  to  independently  conduct  measurements  on  a  sample  of  digital  TV  receivers, 
 we  ask  if  there  are  specific  parameters  that  we  should  measure.  If  so,  which  parameters  should  we  measure  and  what  useful  information  will  they  provide?  Finally,  we  ask  if  there  are  significant 
 differences  in  digital  receiver  performance  quality,  should  those  differences  be  factored  into  the  determination  of  whether  a  household  is  unserved  by  an  adequate  digital  signal?  Are  consumers  aware  of 
 any  such  differences  so  that  they  can  take  them  into  account  when  obtaining  DTV  equipment  in  order  to  assure  themselves  that  they  can  receive  signals  at  the  levels  available  at  their  residences?  Commenting 
 parties  who  believe  that  digital  receiver  quality  should  be  a  factor  are  requested  to  provide  detailed  analysis  and  explain  how  receiver  quality  can  be  used  in  ascertaining  whether  a  household  is  unserved. 
 Finally,  we  ask  commenters  to  discuss  how  any  limitations  in  receivers  can  be  mitigated  by  using  higher  performance  antennas  or  auxiliary  devices. 


 18.  DTV  receiver  interference.  A  radio  receivers  immunity  to  interference  is  dependent  on  a  number  of  factors  in  its  technical  design  and,  in  addition,  on  the  characteristics  of  the  signals  it  receives.  These 
 factors  may  be  closely  related  and  possibly  interdependent,  and  a  receivers  performance  in  one  factor  may  often  affect  its  performance  in  others.  The  factors  determining  receiver  immunity  performance 
 generally  include  selectivity,  sensitivity,  dynamic  range,  automatic  RF  gain  control,  shielding,  modulation 
 346  See  In  The  Matter  of  Advanced  Television  Systems  And  Their  Impact  Upon  the  Existing  Television  Broadcast 
 Service,  Memorandum  Opinion  and  Order  on  Reconsideration  of  the  Sixth  Report  and  Order,  MM  Docket  No.  87-  268,  13  FCC  Rcd.  7418,  7551  (1998)    171. 


 347  See  Report  and  Order  and  Further  Notice  of  Proposed  Rulemaking,  in  MM  Docket  No.  00-  39  (first  DTV 
 periodic  review  proceeding),  16  FCC  Rcd  5946  at    96. 
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 method,  and  signal  processing.  Receiver  selectivity  is  the  ability  to  isolate  and  acquire  the  desired  signal  from  among  all  of  the  undesired  signals  that  may  be  present  on  other  channels.  Sensitivity  is  the  measure 
 of  a  receivers  ability  to  receive  signals  of  low  strength.  Greater  sensitivity  means  a  receiver  can  pick  up  weaker  signals.  348  Dynamic  range  is  the  range  of  the  highest  and  lowest  received  signal  strength  levels 
 over  which  the  receiver  can  satisfactorily  operate.  The  upper  side  of  a  receivers  dynamic  range  determines  how  strong  a  received  signal  can  be  before  failure  due  to  overloading  occurs.  Automatic  RF 
 gain  control  allows  a  receiver  to  adjust  the  level  of  a  received  signal  as  it  appears  at  the  units  signal  processing  and  demodulation  sections. 


 19.  We  request  comment  information  on  whether,  and  if  so,  how  to  account  for  factors  such  as  signal  attenuation  from  structural  penetration,  external  interference  sources  (that  is,  undesired  signals  from  both 
 digital  television  and  analog  television  stations  using  either  the  same  or  adjacent  channels  in  nearby  markets),  foliage,  and  man-  made  clutter  when  determining  whether  a  household  is  unserved  by  an 
 adequate  digital  signal.  We  note  that  many  factors  can  affect  the  reception  of  radio  frequency  signals  and  the  ability  of  a  receiver  to  resolve  these  signals  and  produce  a  picture.  Most  notably,  interference  from 
 both  co-  channel  and  adjacent  channel  TV  transmitters  could  cause  interference  to  the  desired  signal.  Selectivity  is  a  central  factor  in  the  control  of  adjacent  channel  interference.  349  However,  we  also  note 
 that  different  receiver  designs  may  account  for  the  differing  abilities  of  receivers  to  reject  greater  or  lesser  amounts  of  interference.  We  request  comment  on  the  interference  rejection  capabilities  of  digital  TV 
 receivers  and  satellite  set-  top-  boxes  with  built-  in  off-  air  receivers. 
 20.  We  also  note  that  external  forces  can  affect  the  signal  that  ultimately  reaches  a  TV  receiver.  These  include  natural  and  man-  made  structures,  such  as  structures,  terrain,  trees,  etc.,  that  lie  between  the 


 transmitter  and  the  receiver.  These  types  of  obstructions  can  affect  a  signal  in  various  ways.  First,  they  attenuate  the  signal  so  that  the  actual  signal  received  is  weaker  than  that  predicted  in  the  absence  of  any 
 such  obstructions.  In  this  connection,  we  again  note  that  indoor-  mounted  antennas  will  generally  receive  weaker  signals  than  outdoor-  mounted  antennas.  Second,  obstructions  can  create  multipath  interference 
 where  signals  that  bounce  off  structures  arrive  at  the  receiver  at  different  times.  Multipath  interference  occurs  when  DTV  signals  arrive  at  the  receiver  via  different  paths.  These  signals,  although  they  originate 
 from  the  same  transmitting  source,  are  out  of  phase  and  can  cause  severe  interference  that  can  result  in  the  complete  loss  of  the  digital  service.  Given  these  effects,  we  request  comment  on  how  well  digital  TV 
 receivers  and  satellite  set-  top-  boxes  with  built-  in  off-  air  receivers  perform  in  these  less  than  ideal  conditions.  Should  such  performance  specifications  be  taken  into  account  by  the  Commission  in 
 determining  whether  a  household  is  unserved  by  an  adequate  digital  signal?  Commenting  parties  who  propose  that  such  factors  be  accounted  for  should  provide  detailed  information  regarding  how  these 
 factors  could  be  used  and  applied  to  individual  situations.  What  additional  factors,  if  any,  should  be  included  when  determining  the  availability  of  a  DTV  signal  at  an  individual  location? 


 21.  Summary.  In  sum,  we  request  comment  and  information  regarding  how  to  determine  whether  any  household  is  unserved  by  an  adequate  digital  television  network  signal.  This  instant  inquiry  addresses  the 
 particular  concerns  that  Congress  has  specified  in  section  204(  b)  of  the  SHVERA,  and  the  information  gathered  here  will  be  used  to  prepare  the  requisite  report  to  Congress.  Commenting  parties  should  be  as 
 specific  as  possible  in  providing  information  and  describing  how  such  information  can  be  applied  to  the  determination  of  household  eligibility  for  reception  of  satellite  providers  retransmissions  of  distant  DTV 


 348  Greater  sensitivity  can  also  result  in  reception  of  unwanted  signals  at  low  levels  that  then  must  be  eliminated  or 
 attenuated  by  the  selectivity  characteristics  of  the  receiver. 
 349  There  are  several  ways  to  describe  the  selectivity  of  a  radio  receiver.  One  way  is  to  simply  give  the  bandwidth 
 of  the  receiver  over  which  its  response  level  is  within  3  dB  of  its  response  level  at  the  center  frequency  of  the  desired  signal.  This  measure  is  often  termed  the  bandwidth  over  the  -3db  points.  This  bandwidth,  however,  is 


 not  necessarily  a  good  means  of  determining  how  well  the  receiver  will  reject  unwanted  frequencies.  Consequently,  it  is  common  to  give  the  receiver  bandwidth  at  two  levels  of  attenuation;  for  example,  -3dB  and  -60 
 dB.  The  ratio  of  these  two  bandwidths  is  called  the  shape  factor.  Ideally,  the  two  bandwidths  would  be  equal  and  the  shape  factor  would  be  one.  However,  this  value  is  very  difficult  to  achieve  in  a  practical  circuit. 
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 network  signals.  Finally,  commenting  parties  who  believe  that  our  applicable  rules  or  Federal  statutes  should  be  modified  are  requested  to  state  with  particularity  the  rule  and/  or  statutory  modifications  they 
 advocate. 


 ORDERING  CLAUSE 
 22.  Accordingly,  IT  IS  ORDERED  that,  pursuant  to  Section  339(  c)  of  the  Communications  Act  of  1934,  as  amended  by  the  Satellite  Home  Viewer  Extension  and  Reauthorization  Act  of  2004,  this  Notice 
 of  Inquiry  IS  ADOPTED. 


 FEDERAL  COMMUNICATIONS  COMMISSION 


 Marlene  H.  Dortch  Secretary 
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 E-  1 
 APPENDIX  E 
 COMMENTS  AND  REPLY  COMMENTS  TO 
 NOTICE  OF  INQUIRY 
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