NTIA-Report-81-77

Proposed Techniques for

Adding FM Broadcast Stations

in a Major Market

Part II

E.J. Haakinson

u.s. DEPARTMENT OF COMMERCE

Malcolm Baldrige, Secretary

Bernard J. Wunder, Jr., Assistant Secretary

for Communications and Information

July 1981

TABLE OF CONTENTS

LIST OF FIGURES

LIST OF TABLES

ABSTRACT

Page

iv

v

1• INTRODUCTION 1

1.1

1.2

Purpose

Objectives

1

2

2.

3.

ANALYTICAL APPROACH

DEMONSTRATION

2

3

3.1

3.2

3.3

3.4

Selection of Market

Current Assignments

Potential New Assignments

Alternatives for Proposed Facilities

4

4

6

7

4.

5.

6.

CONCLUSIONS

RECOMMENDATIONS

REFERENCES

iii

15

19

20
Figure

LIST OF FIGURES

Page

1 Commercial directional antennas and patterns for FM

broadcast band. Patterns are shown on a voltage scale 9

2 Proposed channel 268 at 10 kW, with a 300 ft (91.4 m) HAAT

omni-directional antenna • • • • • • • 11

3 Interference as calculated by using existing protection standards to co-channel and second-adjacent-channel stations on

channels 268 and 270 from a proposed facility on channel 268 12

4 Interference as calculated by using proposed protection standards to co-channel and second-adjacent-channel stations on

channels 268 and 270 from a proposed facility on channel 268 13

5 Proposed channel 268 at 10 kW, with a 300 ft (91.4 m) HAAT,

directional antenna • • • • • • • • • 14

6 Interference as calculated by using existing protection

standards to co-channel and second-adjacent-channel stations

from a proposed facility having a directional antenna • • • • 16

7 Interference as calculated by proposed protection standards

to co-channel and second-adjacent-channel stations from a

proposed facility having a directional antenna • • • • • • • •• 17

iv
LIST OF TABLES

Table Page

1

2

3

4

Commercial and Non-commercial Radio Stations in Large

Markets, 1979 (From FCC, (1979) Table 3)

Channel Assignments and Facility Characteristics of the

Washington, DC, FM Broadcast Stations ••••••

Signal-to-Interference Protection Ratios for New Assignment

Demonstration • • • • . . • • . • • • • • • . . . • •

Proposed New Washington, DC, FM Broadcast Assignments •

4

5

7

8

5 Proposed Facilities for Potential FM Stations in

Washington, DC • • • • • • • • • •• ••• • • • •• 18

v

PROPOSED TECHNIQUES FOR ADDING FM BROADCAST

STATIONS IN A MAJOR MARKET, PART II

Eldon J. Haakinson*

This is a companion document to another NTIA Report, "Proposed

Techniques for Adding FM Broadc:::ast Stations Ln a Major Market".

Increasing the number of assignments is possible if: 1) co-siting

of second- and third-adjacent-channel transmitters is allowed, 2)

directional antennas to control both signal coverage and interference are used, 3) reasonable changes to the signal-tointerference protection ratios for co-channel and adjacent-channel

operation are adopted, 4) protection to existing facilities rather

than maximum allowed antenna height and transmitter power is

granted, and 5) the effects of terrain on coverage and interference are considered. To demonstrate the approach of adding

assignments to a saturated major market, this second report shows

how the number of FM broadcast stations in the Washington, DC,

market could be increased from the present 13 commercial and noncommercial stations to 21 assiqrtments.

Recommendations are made which, if adopted, could increase

significantly the number of FM broadcast stations in almost all

markets.

Key words: co-sited transmitters; directional antennas; FM

broadcast; spectrum utilization; terrain

1 • INTRODUCTION

1.1 Purpose

Under the current FCC rules, the top 50 FM broadcast radio markets in the

United States are saturated; that is, nearly all of the slots in the Table of

Assignments (FCC, 1980) are assigned. However, the FM band in these markets

is "filled to capacity" only because of the FM rules (FCC, 1962) which

establish the Table of FM Assignments. There have been many improvements,

over the past 20 years, in the FM broadcasting and receiving equipment and in

our ability to predict FM broadcast coverage including both signals and

interference; these improvements and techniques could allow many new FM

broadcast assignments in the major markets.

The purpose of this study is to investigate the technical capacity of the

FM broadcast spectrum and determine if today's equipment and techniques would

*The author is with the Institute for Telecommunication Sciences, National

Telecommunications and Information Administration, U.S. Department of

Commerce, Boulder, CO 80303.
allow utilization of the FM spectrum to be increased, without decreasing the

listening quality of FM radio. To bring about the increased capacity, we will

consider:

1. the co-siting of second- and third-adjacent-channel transmitters,

2. the use of directional antennas to control both coverage and

interference,

3. the effects of reasonable changes to the signal-to-interference

protectional ratios for co-channel and adjacent channel operations,

4. the consideration of actual facilities rather than maximum allowed

antenna height and transmitter power, and

5. the effects of terrain on signal coverage and interference.

1.2 Objectives

The study's objectives were listed in the first report (Haakinson,

1980). In this report we will use the same approach as outlined in the first

report to determine how many new PM broadcast stations could be introduced in

another major market.

2. ANALYTICAL APPROACH

We will use computer-based analytical tools (Hufford, 1977) to compute

the area and population covered by the desired signals and by the

interference. The tools allow us to analyze all of the stations (both

existing and proposed), using the same rules, the same data base, and the same

1 methodology. The approach is:

1I n a fully developed system for analyzing FM applications or for engineering

new facilities, the selection of the best facility/coverage alternative will

involve the station owners. For the new owner, "best" may be limited by:

1) how much he/she is willing to pay for site selection with terrain

features, transmitter power, antenna tower height, directional

antennas, etc., or

2) where or what size of audience he/she is trying to reach.

Using tools such as proposed here, the new owner can analyze for

himself/herself the trade-offs between transmitter antenna site, transmitter

power, antenna height, directional antenna patterns, and coverage area.

2
1. To define the signal level to be protected for each class,

2. To define the minimum allowed signal-to-interference (protection)

ratio required at the protected signal contour,

3. To compute the protected signal contour for an existing station,

4. To evaluate facility alternatives for a proposed new station or a

modified existing station, and

5. To compare area and population of coverage for the alternatives.

3. DEMONSTRATION

In this section we will choose a major FM market to demonstrate how we

propose to increase the capacity of the selected market's "saturated" FM

broadcast band. we will use the approach as described in Section 2. After

selecting the market, we will determine from the FCC data base the locations

and station characteristics of the existing assignments in the region. We

propose to increase the number of stations by adding second- and thirdadjacent-channel stations, by adding IF-response-channel stations, by using

directional antennas, and by using terrain effects to determine actual

coverage and interference contours. Finally, for each proposed channel

assignment, we will demonstrate what potential area and population are covered

for proposed values of transmitter site location, power, antenna height, and

directional antenna pattern.

3.1 Selection of Market

We have chosen the Washington, DC, region, one of the top 10 radio

markets (see Table for comparative ranking), to demonstrate the addition of

new assignments to a major market.

3.2 Current Assignments

We have searched for and considered in the study all of the FM

assignments2 in the FCC data base within 150 mi (241.4 km) of our Washington,

DC, reference location (38.9400 deg north, 77.1000 deg west). The 150-mi

range includes all stations that could be co-channel with proposed

2 The complete list is available from the author.

3
Table 1. Commercial and Non-commercial Radio Stations in

Large Markets, 1979 (From FCC (1979) Table 3)

Total # Commercial Statio"," Noncommercial Statio""

Stations Market # AM # FM # NPR #Other

64 Los Angeles 29 28 4 3

59 Chic.a~ 22 24 1 12

M New 'ork 23 22 3 6

42 San Francisco 18 16 3 5

40 Boston 16 15 2 7

37 Dallas-Fort Worth 16 15 1 5

36 St. Louis 14 11 1 10

36 Seattle 19 12 1 4

36 Washington, D.C. 18 13 2 3

35 Detroit 15 18 I I

35 Pittsburgh 18 12 2 3

34 Philadelphia 15 14 1

"

31 Atlanu, 18 8 I

"

31 Houston 14 12 1 4

31 Miami-Miami Beach 13 14 1 3

30 ~orlolk-Porl.'lmouth-Newport

News-Hampton 14 11 1 4

30 Minneapolis-Sl. Paul 15 7 3 5

29 Tampa-St. Petersburg 18 9 1 1

28 Cleveland 11 13 1 3

28 Phoenix 19 8 1 0

28 Portland 15 10 3 0

28 San DieF;o 13 12 1 2

28 Denver 17 10 1 0

27 Baltimore 13 10 2 2

25 Cincinnati 11 8 1 5

2[, Kans..., C~' 11 10 1 3

24 Hartford- ew Britian 9 10 U 5

24 ~lilwl1ukl'(! 10 11 I 2

24 San Antonio 13 9 0 2

23 Honolulu 17 5 0 1

23 Jacksonville 14 7 1 1

22 Albany-Schcncctady-Troy 9 8 2 3

22 Louisville 11 7 3 1

22 f.krnl'his 10 7 1 4

22 New Orlean. 11 8 1 2

22 Oklahomu City 9 12 0 1

22 Orlando 9 9 0 4

21 Fresno 12 7 1 1

21 Illdillnal'Oli~ H 6 1 6

21 Rivcrsi- ,·-5,10 Br-rnardinoOutnrio 9 II 1 3

21 Albuquerque 12 6 0 3

20 Hirmin~hllm, Ala. n 7 1 1

20 Buffalo Il 9 3 0

20 naleth-Durham 10 6 0 4

20 Snit "'.l' Cily 14 6 0 0

20 Spokane lU 6 0 4

19 San Junn 12 6 1 0

19 Nn..,h,'illl' lU 6 1 2

19 Sacramento 9 9 0 I

19 Scrnnton 10 5 1 3

18 Hichmontl, Va. 11 5 1 1

III Columbus. Ohio 7 6 3 2

18 Sl'rin;~fil'ld-Chicop<'C-Holyoke 9 3 0 6

18 Svracusc 8 8 1 1

17 COlorudo ~rinl:" 8 7 0 2

17 Portland, aine 6 10 1 0

17 Greensboro, N.C, 8 s 0 4

17 Tucson 10 5 2 0

17 \\'c.l Palm Beach 9 6 1 1

17 F.I P..."" 10 6 1 0

16 Chutta noogn l:\ 6 0 2

16 Columbia, S.C. 6 6 1 3

16 I"..-hesler, N.Y. 6 7 1 2

15 Alh-ntown, I'n. 7 5 0 3

4
Table 2. Channel Assignments and Facility Characteristics of the

Washington, DC, FM Broadcast Stations

Antenna

Call Power Height Above Location

Channel Sign Class ERP Average Terrain Latitude Longitude

(kW) (ft) (m) (deg N) (deg W)

203 WAMVFM B 50 500 152.4 38.9358 77 .0925

207 WPFM B 50 410 125.0 38.9358 77.0925

211 WGTBFM B 7 440 134.1 38.9358 77 .0925

215 WETAFM B 75 610 185.0 38.8917 77.1319

230 WKYS B 50 480 146.3 38.9400 77.0817

242 WHURFM B 24 670 204.2 38.9503 77.0797 lJl

246 WASH B 23 690 210.3 38.9558 77.0825

254 WMZQ B 50 490 149.6 38.8867 77.2014

258 WGAYFM B 21 770 234.7 38.9636 77.1050

262 NEW B 20 485 147.8 38.8867 77.2014

266 WWDCFM B 50 500 152.4 39.0003 77.0578

278 WGMSFM B 47 510 155.5 38.9358 77.0925

297 WRQX B 36 590 179.8 38.9503 77.0797
Washington, DC, Class B stations. Table 2 lists the channels assigned to

Washington, DC, and the stations' characteristics. There are 10 noncommercial and commercial assignments serving Washington, DC, whose

transmitters are located within 1.5 mi (2.4 km) of one another. In addition,

4 transmitters are co-sited at one location (channels 203/207/211/278), and 2

transmitters are co-sited at two other locations (channels 242/297 and

channels 254/262). In total, there are 17 transmitters clustered within 7 mi

(11.3 km) of one another serving Washington, DC, and other communities. All

of the Washington, DC, assignments are separated by at least 4 channels;

Baltimore's 10 Class B stations have been given assignments that alternate in

the every-fourth-channel assignment pattern with Washington, except for

Baltimore's Channel 205 which is a second-adjacent-channel assignment to

Washington's Channels 203 and 207. Other assignments in the every-fourthchannel pattern have been given to Takoma Park, Bethesda, Arlington,

Woodbridge, etc. Thus, by the FCC's current separation rules, the Washington,

DC, FM broadcast band has reached capacity.

3.3 Potential New Assignments

Our first step in deciding whether new assignments may be introduced is

to determine what signal level is to be protected. For this example, we will

stay with the present rules and use the equivalent field strengths at 40 mi

(64.4 km) for Class B stations and at 15 mi (8.05 km) for Class A stations.

We will use 55 dB Vim (sometimes shortened to dBu) for Class B (the signal

strength at 40 mi for a full facility class B station) and 59 dB Vim for

Class A as the signal levels to be protected. Our next step is to decide what

signal-to-interference protection ratios should be used. Table 3 shows what

we believe to be reasonable ratios based upon today's good quality receivers

and compares the ratios with the current requirements given by the FCC

(1962). These proposed values are based on measurements of receivers as

reported in popular audio magazines and by Quadracast Systems, Inc. (1979).

From these data, today's receivers provide 30 dB of audio signal-tointerference ratio when the rf signal-to-co-channel interference ratio is 1 to

2 dB and when the rf signal-to-second adjacent channel interference ratio is

-50 dB.

6
Table 3. Signal-to-Interference Protection Ratios

for New Assignment Demonstration

Interference

Condition

Co-channel

Adjacent channel

First

Second

Third

IF Response

Proposed

Required Signal-to-Interference

Protection Ratio

(dB)

14

o

-50

-50

-50

Current

Required Signal-toInterference

Protection Ratio

(dB)

20

6

-20

~o

Assuming that we are now free to test vacant channels for new assignments, Table 4 shows where we will attempt to bring new stations to

Washington, DC. If all could be successfully introduced, the total number of

FM broadcast stations assigned to Washington, DC, would increase from 13 to 24.

3.4 Alternatives for Proposed Facilities

In this section we will provide some possible facility characteristics for

the proposed assignments given in Table 4. All of the assignments will be made

to serve Washington, DC, although in practice we probably would want some of the

stations to cover surrounding communities. To keep the interference to

manageable and acceptable levels, we will co-site (wherever it is feasible) the

facilities with existing second- and third-adjacent-channel transmitters, and we

will use directional antennas for 1:he proposed facilities. Finally, we will

adjust transmitter power, antenna height, and the directional pattern to give

acceptable levels of coverage and interference. When we compute the

interference contours, we will use both sets of interference thresholds as given

in Table 3; i.e., plots will be given with the current interference thresholds

and plots will be given with the proposed interference thresholds.

For this study when directional antennas are used to reduce interference

effects, we will utilize one of three simple dipole arrays for demonstration.

Directional antenna 1 is a single dipole with a reflector to give the pattern

7
Table 4. proposed New Washington, DC, FM Broadcast Assignments

Proposed station

Channel

209

213

232

244

~8

252

260

264

268

276

284

Proposed Station Location and Antenna Pattern

(If Different From Omni-directional)

Co-site with channels 207 and 211's transmitter

Co-site with channel 211's transmitter, near

215's transmitter

Co-site with channel 234's transmitter, near

230's transmitter

Co-site with channel 242's transmitter, near

246's transmitter

Co-site with channel 246's transmitter,

directional antenna needed with null towards

250's transmitter

Co-site with channel 254's transmitter,

directional antenna needed with null towards

250's transmitter

Co-site with channel 258's transmitter, near

262's transmitter

Co-site with channel 266's transmitter, near

262's transmitter

Co-site with channel 266's transmitter,

directional antenna needed with null towards

270's transmitter

Co-site with channel 278's transmitter

directional antenna needed with null towards

274's transmitter

Co-site with channel 286's transmitter,

directional antenna needed with null towards

282's transmitter

8

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i,
3

,

<',

\

,

,

£_-

\

\

--~

-- s -----------1

,

,>

">

/

'v/

3

2

1

r --

I

. I./

--,I

.

1

Figure 1. Commercial directional antennas and patterns for FM

broadcast band. Patterns are shown on a voltage scale.

9
shown in Figure 1. Directional antenna 2 has two dipoles, with reflectors,

offset 90 deg to give the second pattern shown in Figure 1. directional antenna

3 has two dipoles, with reflectors, offset by 120 deg to give the third pattern

shown in Figure 1. Of course, there are many other patterns that are possible

and could be used in place of these three.

As an example, we will consider a proposed assignment on Channel 268. From

the FCC's FM data base, there are two co-channel assignments, i.e., WFVAFM

located in Fredericksburg, VA, and WAYZFM located in Waynesboro, PA, and one

second-adjacent channel assignment, i.e., WLIF located in Baltimore. We propose

to site the new transmitter near either channel 266 or 272 (whose transmitter's

are located less than 0.8 mi (1.3 km) from each other). This follows our

recommendation to co-site new transmitters with existing second- and thirdadjacent channel transmitters. The coverage from a 10 kW, 300 ft (91 m) HAAT

(height above average terrain) transmitter, located at 39.0003 deg north and

77.0578 deg west, to the 55 dB ~v/m contour is shown in Figure 2. The number of

people within this contour is estimated to be 2,760,800 and the area served is

1699 mi2or 4400 km2• The method of computing the signal coverage uses the FCC

curves F(50,50) as modified by the local terrain (Hufford, 1977).

To compute the effects of interference, we will use the FCC curves F(50,10)

and the current set of interference criteria as given in Table 3. The results

are plotted and shown in Figure 3. The solid contours are the coverage contours

from the existing co-channel and second-adjacent-channel stations (WAYZFM,

WFVAFM, and WLIF). The dashed contours indicate where the interference

criterion has been met and the cross-hatched areas indicate regions of

unacceptable interference within the coverage contour. For each assignment, we

have listed the computed estimate of population and area within the service

(solid) contour. Below that, we have listed the population and area that is

within the coverage contour but that also receives interference above the stated

criterion (dashed contour). Figure 4 illstrates how the interference regions

change when the proposed interfernce criterion of Table 3 is used.

To remove the interference outside of the coverage contours, we could

reduce the proposed transmitter's power or antenna height. Instead, we propose

to use a directional antenna.

Figure 5 shows the coverage from a directional antenna with a slight

modification from that shown for antenna number 3 in Figure 1 (we have

1 0
coverage

Pop. 2,760,800

Area == 4400 km2

1699 mi 2

proposed

transmitter

location

50 km

30 mi

Figure 2. Proposed channel 268 at 10 kW, with a

300 ft (91.4 m) HAAT omni-directional antenna.

1 1
50 km

30 mi

WLIF

Coverage

Pop. = 2,970,500 }

Interference

Area = 11,568 km}2 7

Pop. 243,700

Area = 272 km2

55 dBu

-20 dB

Victim

transmitter V

location

Victim transmitter

location

WAYZFM

Coverage }

pop. = 91,500

Area = 1072 km2

Interference }

Pop. = 5000

Area = 64 km2

Interfering

transmitter

location

S 55

S

S/I = 20

WFVAFM

Coverage

pop. = 58,300

Area = 2016 km2

Interference

pop. 26,900

Area = 752 km2

S/I 20

Figure 3. Interference as calculated by using existing protection

standards to co-channel and second-adjacent-channel

stations on channels 268 and 270 from a proposed facility

on channel 268.

12
WAYZFM

Coverage

Pop. = 91,500

Area = 1072 km2

Interference

None

14 dB I

~\ <,

WFVAFM

Coverage

Pop. = 58,300

Area = 2016 km2

Interference

Pop. 15,000

Area = 336 km2

S/I

50 km

30 mi

WLIF

Coverage

Pop. = 2,970,500

Area = 11,568 km2

Interference

Pop. 211,500

Area = 240 km2

Figure 4. Interference as calculated by using proposed protection standards

to co-channel and second-adjacent-channel stations on channels 268

and 270 from a proposed facility on channel 268.

1 3
Coverage

Pop_ 1,874,900

Area = 2368 km2

914 mi2

50 km

30 mi

Figure 5. Proposed channel 268 at 10 kW, with a 300 ft

(91.4 m) HAAT, directional antenna.

14
suppressed the small lobe appearing at 0 deg in the pattern). The population

served has now dropped to 1,874,900 (a loss of 32 percent of the population

compared to that covered by an omni-directional antenna) and the area to

2368 km3 (a loss of 46 percent). Figure 6 shows the coverage and interference

by the existing stations using the current interference criteria; Figure 7 shows

the results using the proposed criteria. Note in the latter case, there is no

predicted interference within the existing service contours.

For this example, we have 1) used existing characteristics for each

station to compute its coverage contour, 2) co-sited our proposed station with

existing second- and/or third-adjacent channel transmitters, 3) used a proposed

set of interference criteria, 4) utilized a directional antenna for the

proposed station, and 5) utilized terrain effects in the calculation of both

signal coverage and interference. A. similar set of plots3 for the other

proposed stations were computed.

In Table 5, we have summarized the results of locating new stations in

Washington, DC.

4. CONCLUSIONS

An examination of the background on the FM broadcast spectrum capacity

(Haakinson, 1980) has uncovered some reasons why today's major markets are

"saturated" :

1. the FCC rules were developed around good quality receivers of the late

fifties' technology,

2. the rules assumed that all stations eventually would have the maximum

allowed antenna height and transmitter power (maximum facilities) for

their class,

3. the rules disallowed the use of terrain-dependent propagation

algorithms, and

3A complete set of the plots for the other proposed stations is available from

the author.

15
IflAYZFM

Coverage

pop. = 91,500

Area = 1072 km2

Interference

pop. 1300

Area = 16 km2

S/I

WFVAFM

Co~erage

pop. = 58,300

Area = 2016 km2

Interference

pop. 2900

Area = 96 km2

50 km

30 mi

WLIF

Coverage

Pop. = 2,970,500

Area = 11,568 km2

Interference

pop. 15,500

Area = 16 km2

Figure 6. Interference as calculated by using existing protection

standards to co-channel and second-adjacent-channel stations

from a proposed facility having a directional antenna.

16
SII

50 km

30 mi

WLIF

Coverage

Pop. = 2,970,500

Area = 11,568 km2

Interference

None

v

'\

/

14 dB

v

WFVAFM

Coverage

Pop. = 58,300

Area = 2016 km2

Interference

None

WAYZFM

Coverage

Pop. = 9 1 , 50 0

Area = 1072 km2

Interference

None

Figure 7. Interference as calculated by proposed protection standards

to co-channel and second-adjacent-channel stations from a

proposed facility having a directional antenna.

17
Table 5. Proposed Facilities for Potential FM stations in Washington, DC

Antenna Estimated

Height Above Directional Co-located with Requires New Population

Channel Power Average Antenna 2nd Adjacent Channel S!r Receiver Within

Number ERP Terrain Pattern No. Transmitters Thresholds 55 dBlJ contour

(kW) ( ft) (m)

209 10 400 121.9 1 yes no* 1,791,700

213 50 500 152.4 none yes yes 3,311,900

f-'

00 232 25 300 91.4 1 yes yes 2,984,700

244 20 500 152.4 1 yes yes 1,783,800

248 10 300 91.4 3 yes yes 2,144,800

252} Unavailable; too much second-adjacent-channel interference

260

264 10 300 91.4 3 yes yes 2,261,800

268 10 300 91.4 3 (modified) yes yes 1,874,900

276 Unavailable; too much second-adjacent-channel interference

284 10 300 91.4 2 yes no* 1,601,500

* less than one percent of population receives interference

with present protection standards
4. the rules disallowed the use of directional antennas for assignment

purposes.

Using these and other guidelines, the FCC adopted a Table of Assignments

for FM broadcast stations based on minimum mileage separations between

transmitters. As a consequence, there are at most 25 out of a possible 100

channels assigned in anyone location, when the FCC rules are strictly

followed.

In this report, we have selected one of the ten most saturated FM

broadcast markets and have demonstrated what we believe are reasonable methods

for increasing that market's number of FM stations. In particular, we have

shown that the number of PM stations operating in the Washington, DC, region

could be increased from the preaent; 13 stations to 21 stations, given the

conditions set forth in this report. This was accomplished by using existing

facilities rather than maximum facilities, co-siting of second- and thirdadjacent channel transmitters with existing transmitters, terrain-dependent

propagation algorithms, and directional antenna patterns when required and/or

otherwise helpful.

5. P.ECOMMENDATIONS

We make several recommendations regarding the FM broadcast band:

1. the FCC should use techniques such as those shown in this report to

examine easily the new applications for coverage and interference,

2. the effects of terrain should be included in the prediction of signal

coverage and interference (although terrain did not have a significant

influence in the relatively flat Washington, DC, area),

3. directional antennas should be allowed,

4. co-siting of second- and third-adjacent-channel transmitters with existing

transmitters should be encouraged,

5. service area protection should be granted to stations based upon their

present (or seriously proposed) facilities rather than protection to the

maximum facility allowable for the station's class, and finally,

6. the FM broadcast receiver protection standards should be developed around

present-day, good-quality receivers.

We believe that if these recommendations were adopted, the number of FM

stations could be increased significantly in almost all markets.

19
6. REFERENCES

Haakinson, E.J. (1980), Proposed techniques for adding FM broadcast stations

in a major market, NTIA Report 80-44, NTIS Access. No. PB 81-108433.

Hufford, G.A. (1977), Techniques for the evaluation of proposed VHF TV dropins, OT Report 77-112, NTIS Access. No. PB 271212/AS.

Quadracast Systems, Inc. (1979), Comments to the FCC further notice of inquiry

on quadraphonic broadcasting, FCC Docket 21310.

FCC (1962), Revision of FM broadcast rules, Docket No. 14185, First Report and

Order.

FCC (1979), Deregulation of radio, Docket No. 79-219, Notice of Inquiry and

Proposed Rule Making.

FCC (1980), Rules and regulations, Part 73, Radio broadcast services, 73.202,

FCC.

20
FORM NTIA-29 U.S. DEPARTMENT OF COMMERCE

(4-80) NATL. TELECOMMUNICATIONS AND INFORMATION ADMINISTRATION

BIBLIOGRAPHIC DATA SHEET

1. PUBLICATION NO. 2. Gov't Accession No. 3. Recipient's Accession No.

NTIA Report 81-77

4. TITLE AND SUBTITLE 5. Publication Date

PROPOSED TECHNIQUES FOR ADDING FM BROADCAST STATIONS July 1981

IN A MAJOR MARKET, PART II 6. Performing Organization Code

NTIA/ITS-l

7. AUTHOR(S) 9. ProjecVTask/Work Unit No.

8. PERFORMING ORGANIZATION NAME AND ADDRESS 9101124

U.S. Department of Commerce

National Telecommunications and Information Admin. 10. ContracVGrant No.

Institute for Telecommunication Sciences

Boulder, CO 80303

11. Sponsoring Organization Name and Address 12. Type of Report and Period Covered

National Telecommunications and Information Admin. Technical Report

U.S. Department of Commerce 13.

Boulder, CO 80303

14. SUPPLEMENTARY NOTES

15. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or literature

survey, mention it here.)

This is a companion document to another NTIA Report, "Proposed Techniques for

Adding FM Broadcast Stations in a Major Market". Increasing the number of

assignments is possible if: 1) co-siting of second- and third-adjacent-channel

transmitters is allowed, 2) directional antennas to control both signal coverage

and interference are used, 3) reasonable changes to the signal-to-interference

protection ratios for co-channel and adjacent-channel operation are adopted,

4) protection to existing facilities rather than maximum allowed antenna height

and transmitter power is granted, and 5) the effects of terrain on coverage and

interference are considered. To demonstrate the approach of adding assignments

to a saturated major market, this second report shows how the number of FM

broadcast stations in the Washington, DC, market could be increased from the

present 13 commercial and non-commercial stations to 21 assignments.

Recommendations are made which, if adopted, could increase significantly

the number of FM broadcast stations in almost all markets.

16. Key Words (Alphabetical order, separated by semicolons)

co-sited transmitters; directional antennas; FM broadcast; spectrum utilization;

terrain

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