From: troach@netcom.com (Tom Roach)
Subject: Technical hints and 5.6 to 6.6 MHz search
Keywords: NRD-525  NRD-535D
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Date: Thu, 15 Oct 1992 02:49:42 GMT

After a few remarks on technical SWL techniques, I am including some
preliminary results of my signal search project. The preliminary
results consists of 106 signals I intercepted while searching between
5.6 to 6.6 MHz, usually between 1330 and 1430 UTC (0630 to 0730 local).
My listening post is located in San Jose, CA and is quite noise free. My
current equipment complement consists of:
 
1 NRD-525
 
1 NRD-535D with high stability local oscillator.
 
1 Singer Spectrum Analyzer (plug in looks at NRD-525's 455 kHz IF)
 
1 JVC cassette recorder
 
2 Sony Digital Tape Recorders
 
2 oscillscopes (one for looking at audio, second for tuning RTTY)
 
2 M-7000's with monochrome monitors
 
1 BK Model 3011B Digital Display Function Generator
 
1 Sony ICF-2010
 
... and hopefully by this Friday the HOKA Code3.
 
               ====================================
 
Special measurement techniques:
 
As of today I added the BK Model 3011B, a combined signal
generator/frequency counter which will enable me to determine the exact
(plus or minus one Hz) frequency of CW emitters. This is done by free
running the top trace of my oscilloscope at EXACTLY 750 Hz. The BFO of
the NRD-535 is then set so it is precisely 750 Hz above the carrier. I
then examine the audio output of the NRD-535 on a oscilloscope trace
free running at 750 Hz (verified by a single non-drifting 750 Hz sine
wave from the Model 3011B) and tune the NRD-535D receiver till one cycle
of a 750 Hz tone is "stopped", i.e. it doesn't drift across the
oscilloscope trace.
 
The purpose of all this is to do a quality check on unknown origin CW
emitters to see if some are much more stable than others, and if so, to
determine which ones.
 
You can use a similar method on the NRD-525, with no oscilloscope, for
AM signals. Tune the AM signal in USB till the voice seems "right"
(you'll know when it sounds "right" if you try it). Switch to the CW
mode and use the RIT to offset the receiver RF and generate a tone (say
300 Hz) which shows up as .30 on the receiver face. Now aurally
"remember" this tone and offset the receiver tuning (close your eyes!)
in the opposite direction till you hear a tone with the same pitch. If
you do have an o'scope, free run it at a convenient sweep speed till you
stop the sinewave (at both ends of the tuning) from drifting. Log the
RIT values at both points. Say you get plus .40 and minus .36 when the
tones/pitch match. When you press the RIT button a second time, retune
the receiver to the correct frequency by taking half of the difference
and retuning (in this case, downward) by that amount. In our example the
difference was .04 (0.40 minus 0.36 for recent high school grads in the
USA) divided by two. This results in a difference of .02 kHz, which is
(in tens of cycles) the same as 20 Hz. If you were tuned to 5124.00 kHz
when you started, you know the transmitters actual frequency is 5124.00
minus 20 Hz or 5123.98 kHz on the NRD-525 dial. If you have a NRD-535D
under computer control and the SCAN-CAT or SCAN-STAR software you can
actually measure an AM signal's RF to one Hz!
 
This may seem like more trouble than it's worth but by keeping detailed
logs you may find some interesting things. I found that R. Moscow had
two transmitters in Cuba spaced exactly 80 Hz apart in RF. By looking at
my logs over a period of time I had noted that the frequencies were very
stable (always either "a" or "b" but never in between, better known as a
bi-modal distribution to statistic freaks), so I concluded that there
were two stable, but different, Russian transmitters in use on Cuban
soil.
 
Try this technique on Indonesian, Peruvian, South American, African,
etc., tropical band transmitters. I have logs going back several years
which show some transmitters: slightly off frequency, but stable, some
"drifters", and, some always right on the money. You may be able to sort
out new stations on or about the same frequency from old "favorites" by
using these techniques. Sometimes this is a great indicator of a new
catch, or a new transmitter for an old friend.
 
About a year after I started this hobby, I was picking up the Burmese
Army station transmitter with great regularity. This station was reputed
to be a QRP freak's delight; a puny 50 watter in the Burmese jungle. I
imagined spiders, army ants, and insects of all sorts slithering about
its rapidly rusting interior. It was supposedly the great catch of all.
When I examined my logs over a period of time I noticed that this
station was VERY stable in frequency. Since it was supposed to be some
junky jungle kludge transmitter, I started to wonder about my great
"success". When I first picked this station I, of course, attributed my
success in hearing it to my "super" personal skills-  :-) i.e. great
equipment, a noise free environment, and luck of a most unusual sort.
Day after day of hearing this station made me wonder. As a novice, I
contacted a well known SWL "expert" who assured me that my predilection
for measuring RF's to this accuracy was the mark of a equipment snob. In
his published column (we'll leave him nameless) he told me he would
refuse to print any such results without rounding off the frequencies.
This would ensure that his readers would not be offended by some uppity
turkey who had too much money and too little good sense. He assured me
that junky jungle kludge transmitters just don't have that sort of
stability. So ... it couldn't be the Burmese Army station. Being new to
the hobby, I deferred (publically) to the gentleman's all encompassing
wisdom.
 
A couple of years later I read where the famed Burmese Army station had
indeed upgraded its transmitter to a fancy Japanese transmitter with
obviously great stability, and closer to 50 kilowatts output vice 50
watts. Perhaps this purchase was the precursor to the Burmese Army's
rise to its current brutal and dictatorial power.
 
The moral of the story is trust your equipment, keep good logs, and
take all so called "experts" with a grain of salt. This especially
refers to me, as I can make some horrendous errors in both logic and
analysis. Remember, this is a hobby, not an obsession (a very big lie I
tell myself).
 
My next major project is the precise measurement of Russian maritime
RTTY parameters with the Hoka Code3. This equipment allows you to
measure Baud rates with ridiculous accuracy. No mere 96 baud, but
96.0135 baud (or whatever). I will compile my results to see if some
fishing boats have much more stable equipment then others. Why? I
suspect because Russian maritime vessels all serve the Rodina (look THAT
up in your Tom Clancy Hunt for the Red October/Red Storm Rising) as
sometime adjuncts to the intelligence service. If equipment used by so
called shell fish factories or sea tugs stands out parametrically like a
sore thumb, then they may be catching something besides slime eels,
hake, and other critters of the deep. {Read Polar Star by Marin Cruz
Smith for further details). Same goes for the old Soviet Academy of
Science vessels (NIS this or that) and the once great fleet of Space
Event Support Ships. While I treasure my QSL cards from Botswana and
such, there is a VERY interesting side of this hobby for those with the
inclination and/or the equipment to look a little deeper.
 
Finally, any listeners who are SERIOUS (but not necessarily gifted
with equipment) about monitoring Russian communications, please let me
know. A whole world of KRIPTOGRAMMAS, 20101 messages, and lots of other
goodies awaits those who are truly interested. 
 
                    =======================
 
Glossary of unusual words/expressions used in this data base:
 
 
ALL FIVE: Refers to the conglomerate of WWVH, WWV, VNG, BPM and JJY
easily heard on an almost daily basis from my California, close to the
coast, QTH on 5 MHz at 1329 and 1429 UTC.
 
CFL: Confidential Frequency List (8th edition)
[phooey on Klingandclutch!]
 
CHIRPER: CW emitter whose RF stability sucks so badly that depressing
the key to send a morse code character results in a shift in RF which
is heard by the listener as a "chirp" sound in the audio. Stations like
KFH, VAI etc. DO NOT chirp. Chirpers MAY indicate Chinese, Burmese,
Russian, Vietnamese, Laotian or whatever tactical military traffic. Such
traffic is also probably characterized by ever shifting net frequencies.
 
T001C26: Refers to DAT Tape number 001 Cut 26 (I keep these tapes
forever!). Using a DAT recorder, or your VHS deck as an audio recorder
ensures close to perfect playback. No wow or flutter. Thus tapes I made
long before I heard of the HOKA Code3 can be analyzed MEANINGFULLY by
this precise hardware/software combination.
 
Any questions?  Send them to me via INTERNET (troach@netcom.com),
Compuserve (76347,1025), or US SNAIL at 3342 Gateway Blvd., Fremont, CA
94538, USA.
 
Tom Roach
 
              ================================
 
All times UTC
             DATE
RF      TIME MM/DD/YY REMARKS: (BEGINS WITH MODUALTION TYPE)
 
5000.00 1429 09/06/92 AM  DAILY TIME CHECK T001C37
5000.00 1429 09/10/92 AM  WWV, WWVH, BPM, JJY, VNG  ALL PRESENT T002C56 
5000.00 1429 09/11/92 AM  TIME SIGNALS WWV,WWVH,JJY,BPM,VNG  "U" T002C62 
5000.00 1429 09/13/92 AM  DAILY TIME ALL FIVE PRESENT  JJY FAIR T002C69 
5000.00 1429 09/14/92 AM  DAILY TIME SIGS T002C79 
5000.00 1329 09/15/92 AM  ALL FIVE PRESENT JJY = "N" NO RCDNG  
5000.00 1429 09/15/92 AM  ALL FIVE TIME SIGS PRESENT JJY = "N" T002C96 
5600.07 1400 09/02/92 AM POSSIBLY CHINESE OR MALAYSIAN T001C01 
5605.50 1334 09/26/92 CW  CHIRPER T003C08 
5606.00 1409 09/15/92 CW  CHIRPER T002C89 
5610.00 1405 09/02/92 LSB OM UNKNOWN LANGUAGE T001C02 
5612.00 1410 09/02/92 RTTY POSSIBLE (??!) SUC CAIRO 64/582 T001C04 
5612.00 1410 09/02/92 RTTY POSSIBLE (??!) SUC CAIRO 64/582 T001C03 
5612.50 1401 09/25/92 CW  CHIRPER T003C01 
5613.00 1340 09/26/92 CW  CHIRPER T003C09 
5614.00 1418 09/02/92 USB POSS FONECON NOT IN CFL/KLING T001C05 
5615.00 1402 09/25/92 CW  POSSIBLE MILITARY CW NET T003C02 
5620.50 1426 09/02/92 RTTY 96/500 ENCRYPTED  TRY CODE3!! T001C06 
5621.50 1418 09/13/92 USB  RF P/M 0.2 KHZ  MEN IN ORIENTAL LNG T002C63
5623.00 1430 09/02/92 USB MULTIPLE MALES IN CHINESE (?) T001C07 
5624.00 1412 09/15/92 CW  CHIRPER T002C95 
5626.10 1420 09/03/92 CW "W4 W4 W4 US 111 AR" NO CFL T001C09 
5628.00 1348 09/05/92 USB AERADIO  HONOLULU W UNITED 828 & 890  
5632.00 1434 09/03/92 CW "GUHI DE RQKE"  LONG CUT NOT IN CFL T001C08
5633.00 1414 09/02/92 USB SOUNDED LIKE AMERICAN INLAND WATERWAY NO TAPE 
5637.00 1415 09/15/92 USB  MAN IN UNDETERMINED ORIENTAL LANGUAGE T002C91 
5638.00 1422 09/03/92 USB POSS MILITARY   "THIS IS DIXIE HOTEL.." T001C10 
5643.00 1345 09/26/92 USB NANDI, FIJI AERADIO  A/C REPORTED MISSILE! T003C10
5647.70 1435 09/03/92 CW  5 NUMBER GROUPS  "CQ 75" & "27245 21325" T001C11
5655.30 1352 09/26/92 CW  CHIRPER T003C11 
5655.50 1342 09/14/92 CW  CHIRPER  POSS MIL TACTICAL T002C70 
5660.00 1418 09/15/92 1418  CHIRPER T002C92 
5663.00 1421 09/15/92 CW  CHIRPER T002C93 
5673.00 1351 09/04/92 AM YL IN CC  READING WX & Q SIGS LESSON? T001C13 
5681.10 1357 09/04/92 CW "3U7DSM 46374 DN AU NN 60 " T001C14 
5684.00 1344 09/14/92 CW  T002C71 
5691.00 1347 09/14/92 USB  IRKUTSK VOLMET IN RUSSIAN T002C72 
5691.00 1424 09/14/92 USB  PROBABLY KHABAROVSK VOLMET YL SPKNG RR T002C77 
5691.00 1355 09/15/92 USB  VERY WEAK!! T002C84 
5695.30 1407 09/04/92 CW  CHIRPER PROBABLY IN A NET (DUPLEX??) T001C16
5709.00 1412 09/04/92 LSB MENTIONS HURRICANE  INLAND WATERWAY? T002C17 
5714.20 1357 09/14/92 CW  T002C74 
5718.50 1421 09/04/92 CW FAIRLY FAST CW  LOUSY FIST T002C18 
5726.00 1428 09/04/92 USB OM IN CC NOT IN CFL T002C19 
5733.00 1401 09/14/92 USB  ORIENTAL MAN AND WOMAN THAI/LAOTIAN? T002C75 
5749.20 1433 09/04/92 CW  T002C21 
5755.00 1404 09/14/92 FAX  T002C76 
5766.20 1441 09/04/92 USB TWO OM IN SS  SOUNDED LIKE CHECKING LIST T002C23 
5802.20 1452 09/04/92 CW WEAK T002C24 
5839.20 1457 09/04/92 CW WEAK T002C25 
5849.98 1356 09/05/92 AM R. BEIJING  IN RUSSIAN  
5870.40 1412 09/05/92 AM YL IN CC READING NUMBERS  
5880.00 1418 09/05/92 AM R. BEIJING  ENGLISH LESSON  
5965.05 1446 09/05/92 AM PROB RTV MALAYSIA KAJAN RCRD AT 1506 UTC T002C26 
5970.00 1455 09/05/92 AM KAZAKH RADIO  ALMA-ATA  
5979.00 1334 09/06/92 AM POSS CHINESE STATION  WEAK T001C27 
6204.90 1341 09/06/92 USB SEVERAL OM LANG?? SIGNAL RF SLIGHT DRIFT T002C28 
6205.00 1410 09/25/92 USB  MALE RUSSIAN READING NUMBERS T003C03 
6215.53 1346 09/06/92 USB SEVERAL OM  USED ENGLISH FOR ALPHA T002C29 
6218.50 1350 09/06/92 USB SEVERAL OM  RF DRIFTED P/M 0.1 KHZ T002C30 
6220.30 1357 09/15/92 CW  SOUNDS LIKE UPPER PART OF RTTY T002C85 
6220.30 1404 09/15/92 CW  SENDING V's T002C88 
6227.00 1350 09/15/92 USB  RUSSIAN SHIP TO SHORE  STRONG!!  VLAD T002C83 
6227.00 1401 09/26/92 USB  RUSSIAN VOICE SHIP TO SHORE T003C12 
6244.00 1355 09/06/92 RTTY DATA TRANSMISSION  TRY CODE3!! T002C31 
6249.30 1400 09/06/92 CW SEVERAL STATIONS HEARD  QSV T002C32 
6263.50 1405 09/06/92 RTTY SITOR T002C33 
6271.00 1418 09/06/92 CW 16 MILLISECOND PERIOD NOISE ALSO HEARD T002C34 
6287.00 1425 09/13/92 CW  MAGADAN?? T002C68 
6294.00 1425 09/15/92 CW  CHIRPER T002C94 
6302.00 1410 09/26/92 RTTY  RTMS URANIYA QTH= 46 15N/151 00E 50/170 T003C14 
6303.50 1337 09/15/92 RTTY  50/170 SOVIET MARITIME  20101 MESSAGE T002C81 
6304.00 1428 09/15/92 RTTY  RUSSIAN MARITIME 50/170 T002C95 
6307.00 1420 09/13/92 RTTY  SOVIET RTTY T002C66 
6307.00 1420 09/13/92 RTTY  SOVIET RTTY T002C67 
6310.00 1424 09/14/92 RTTY  PB V. SIBIRSHEV  RUSSIAN RTTY 50/170 T002C78 
6310.00 1424 09/14/92 RTTY  PB V. SIBIRSHEV  RUSSIAN RTTY 50/170 T002C80 
6311.50 1414 09/26/92 RTTY  RUSSIAN TK M. SVETLOV VLD/MMF 50/170 T003C15 
6320.50 1427 09/11/92 CW  C/S "VIS"  SYDNEY, AUSTRALIA NO RECORDING
6325.00 1356 09/13/92 AM  POSS CLANDESTINE "VO THE KHMER" T002C65 
6335.00 1418 09/11/92 USB  OM & YL (THAI LANGUAGE??) T002C61 
6348.80 1413 09/11/92 RTTY  50/850  ENCRYPTED ?? T002C60 
6350.00 1403 09/11/92 USB  MAN AND WOMAN IN CONVERSATION T002C57 
6350.00 1406 09/11/92 CW  POOR QUALITY XMTR  SENDING NUMBERS CUT T002C58 
6350.00 1406 09/11/92 CW  POOR QUALITY XMTR  SENDING NUMBERS CUT T002C59 
6369.00 1355 09/11/92 CW  CQ DE KLC  NO RECORDING  
6384.50 1423 09/10/92 CW  CQ DE CKN  NO RECORDING  
6385.00 1420 09/10/92 USB  TWO OM TALKING  WEAK  NO RECORDING  
6389.60 1413 09/10/92 CW  WNU  SLIDELL, LA  NO RECORDING  
6400.90 1408 09/10/92 RTTY  75/866 (??) ENCRYPTED? T002C54 
6412.00 1357 09/10/92 CW  PROB 9GV55 SINGAPORE  NAV WARNING BCST T002C55 
6420.00 1354 09/07/92 USB  TWO MEN ORIENTAL LANGUAGE T002C52 
6445.00 1424 09/07/92 RTTY  75/895 (??) PROBABLY ENCRYPTED T002C51 
6462.00 1420 09/07/92 CW  FUM  PAPEETE NAVAL (FRENCH NAVY) T002C50 
6465.00 1415 09/07/92 CW  PROBABLY GERMAN TFC T002C49 
6467.00 1412 09/07/92 CW  CQ DE JCS   CHOSI, JAPAN T002C48 
6470.00 1411 09/07/92 USB  OM IN ORIENTAL LANGUAGE T002C47 
6477.50 1407 09/07/92 CW WEIRDO  CQ DE ??  OTHER STRONG CW HEARD T002C46 
6488.30 1402 09/07/92 1402  RTTY 96/873  S15+ SIGNAL STRENGTH! T002C45 
6491.50 1350 09/07/92 CW  JOS NAGASAKI, JAPAN T002C45 
6493.00 1356 09/07/92 CW  CQ DE VAI  VANCOUVER, BC T002C43 
6495.50 ???? 09/07/92 CW CHIRPER  TIME UNCERTAIN T002C40
6496.40 ???? 09/07/92 CW  CQ DE FJP6 NOUMEA RADIO, NEW CALEDONIA T002C39
6498.90 1346 09/07/92 CW  T002C41
6510.10 1350 09/07/92 USB  RF DRIFTS T002C42 
6558.00 1923 09/07/92 CW SENDING CUT NUMBERS T002C38 

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