47 CFR 90.309 - Tables and figures.

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§ 90.309 Tables and figures.
(a) Directions for using the tables.
(1) Using the method specified in § 1.958 of this chapter, determine the distances between the proposed land mobile base station and the protected co-channel television station and between the proposed land mobile base station and the protected adjacent channel television station. If the exact mileage does not appear in table A for protected co-channel television stations (or table B for channel 15 in New York and Cleveland and channel 16 in Detroit) or table E for protected adjacent channel television stations, the next lower mileage separation figure is to be used.
(2) Entering the proper table at the mileage figure found in paragraph (a)(1) of this section, find opposite, a selection of powers that may be used for antenna heights ranging from 15 m (50 ft) to 152.5 m (500 ft) (AAT). If the exact antenna height proposed for the land mobile base station does not appear in the proper table, use the power figure beneath the next greater antenna height.
(3) The lowest power found using the tables mentioned in paragraphs (a)(1) and (a)(2) of this section is the maximum power that may be employed by the proposed land mobile base station.
(4) In determining the average elevation of the terrain, the elevations between 3.2 kilometers (2 miles) and 16 kilometers (10 miles) from the antenna site are employed. Profile graphs shall be drawn for a minimum of eight radials beginning at the antenna site and extending 16 kilometers (10 miles). The radials should be drawn starting with true north. At least one radial should be constructed in the direction of the nearest co-channel and adjacent channel UHF television stations. The profile graph for each radial shall be plotted by contour intervals of from 12.2 meters (40 feet) to 30.5 meters (100 feet) and, where the data permits, at least 50 points of elevation (generally uniformly spaced) should be used for each radial. For very rugged terrain, 61 meters (200 feet) to 122 meters (400 foot) contour intervals may be used. Where the terrain is uniform or gently sloping, the smallest contour interval indicated on the topographic chart may be used. The average elevation of the 12.8 kilometer (8 mile) distance between 3.2 kilometers (2 miles) and 16 kilometers (10 miles) from the antenna site should be determined from the profile graph for each radial. This may be obtained by averaging a large number of equally spaced points, by using a planimeter, or by obtaining the median elevation (that exceeded by 50 percent of the distance) in sectors and averaging those values. In the preparation of the profile graphs, the elevation or contour intervals may be taken from U.S. Geological Survey Topographic Maps, U.S. Army Corps of Engineers Maps, or Tennessee Valley Authority Maps. Maps with a scale of 1:250,000 or larger (such as 1:24,000) shall be used. Digital Terrain Data Tapes, provided by the National Cartographic Institute, U.S. Geologic Survey, may be utilized in lieu of maps, but the number of data points must be equal to or exceed that specified above. If such maps are not published for the area in question, the next best topographic information should be used.
(5) Applicants for base stations in the Miami, FL, urbanized area may, in lieu of calculating the height of average terrain, use 3 m (10 ft) as the average terrain height.
Table A—Base Station—Cochannel Frequencies (50 dB Protection) Maximum Effective Radiated Power (ERP) 1
Distance in kilometers (miles): 2 Antenna height in meters (feet) (AAT)
15 (50) 30.5 (100) 45 (150) 61 (200) 76 (250) 91.5 (300) 106 (350) 122 (400) 137 (450) 152.5 (500)
1 The effective radiated power (ERP) and antenna height above average terrain (AAT) shall not exceed the values given in this table.
2 At this distance from transmitter site of protected UHF television station.
260 (162) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000
257 (160) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 800
249 (155) 1,000 1,000 1,000 1,000 1,000 875 775 700 625 575
241 (150) 1,000 1,000 950 775 725 625 550 500 450 400
233 (145) 850 750 650 575 500 440 400 350 320 300
225 (140) 600 575 475 400 350 300 275 250 230 225
217 (135) 450 400 335 300 255 240 200 185 165 150
209 (130) 350 300 245 200 185 160 145 125 120 100
201 (125) 225 200 170 150 125 110 100 90 80 75
193 (120) 175 150 125 105 90 80 70 60 55 50
Table B—Base Station—Cochannel Frequencies (40 dB Protection) Maximum Effective Radiated Power (ERP) 1
Distance in kilometers (miles): 2 Antenna height in meters (feet) (AAT)
15 (50) 30.5 (100) 45 (150) 61 (200) 76 (250) 91.5 (300) 106 (350) 122 (400) 137 (450) 152.5 (500)
1 The effective radiated power (ERP) and antenna height above average terrain shall not exceed the values given in this table.
2 At this distance from the transmitter site of protected UHF television station.
209 (130) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000
201 (125) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 850 750 725
193 (120) 1,000 1,000 1,000 1,000 900 750 675 600 550 500
185 (115) 1,100 1,000 800 725 600 525 475 425 375 350
177 (110) 850 700 600 500 425 375 325 300 275 225
169 (105) 600 475 400 325 275 250 225 200 175 150
161 (100) 400 325 275 225 175 150 140 125 110 100
153 (95) 275 225 175 125 110 95 80 70 60 50
145 (90) 175 125 100 75 50
Table C—Mobile and Control Station—Distance Between Associated Base Station and Protected Cochannel TV Station
[50 dB protection]
Effective radiated power (watts) of mobile unit and control station Distance
Kilometers Miles
200 249 155
150 243 151
100 233 145
50 217 135
25 201 125
10 188 117
5 180 112
Table D—Mobile and Control Station—Distance Between Associated Land Mobile Base Station and Protected Cochannel TV Station
[40 dB protection]
Effective radiated power (watts) of mobile unit and control station Distance
Kilometers Miles
200 209 130
150 201 125
100 193 120
50 185 115
25 177 110
10 169 105
5 161 100
Table E—Base Station Adjacent Channel Frequencies Maximum Effective Radiated Power (ERP) 1
Distance in kilometers (miles): 2,3 Antenna height in meters (feet) (AAT)
15 (50) 30.5 (100) 45 (150) 61 (200) 76 (250) 91.5 (300) 106 (350) 122 (400) 137 (450) 152.5 (500)
1 The effective radiated power (ERP) and antenna height above average terrain (AAT) shall not exceed the values given in this table.
2 At this distance from transmitter site of protected UHF television station.
3 The minimum distance is 145 km (90 miles) where there are mobile units associated with the base station. See sec. 90.307(d).
108 (67) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000
106 (66) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 1,000 750
104 (65) 1,000 1,000 1,000 1,000 1,000 1,000 1,000 825 650 600
103 (64) 1,000 1,000 1,000 1,000 1,000 1,000 775 625 500 400
101 (63) 1,000 1,000 1,000 1,000 1,000 650 450 325 325 225
99 (62) 1,000 1,000 1,000 1,000 525 375 250 200 150 125
98 (61) 1,000 1,000 700 450 250 200 125 100 75 50
96 (60) 1,000 1,000 425 225 125 100 75 50
Table “F”—Decibel Reduction/Power Equivalents
dB reduction below 1 kW ERP permitted (figures rounded)
1 795
2 630
3 500
4 400
5 315
6 250
7 200
8 160
9 125
10 100
11 80
12 65
13 50
14 40
15 30
16 25
17 20
18 15
19 12
20 10
21 8
22 6
23 5
24 4
25 3
26 2.5
27 2
28 1.5
29 1.25
30 1
(b) Directions for Using the Figures.
(1) Determine antenna height above average terrain. (According to § 90.309(a)(4).)
(2) Locate this value on the antenna height axis.
(3) Determine the separation between the LM antenna site and the nearest protected co-channel TV station. (According to § 73.611.)
(4) Draw a vertical line to intersect the LM/TV separation curve at the distance determined in step 3 above. For distances not shown in the graph use linear interpolation.
(5) From the intersection of the LM/TV separation curve draw a horizontal line to the power reduction scale.
(6) The power reduction in dB determines the reduction below 1 kW that must be achieved.
(7) See table F for dB/power equivalents.
(Section 0.231(d) of the Commission's Rules and secs. 4(i) and 303 of the Communications Act, as amended)
[43 FR 54791, Nov. 22, 1978, as amended at 49 FR 36107, Sept. 14, 1984; 49 FR 49837, Dec. 17, 1984; 58 FR 44958, Aug. 25, 1993; 70 FR 19312, Apr. 13, 2005; 72 FR 35197, June 27, 2007]

Title 47 published on 2013-10-01

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  • 2014-08-05; vol. 79 # 150 - Tuesday, August 5, 2014
    1. 79 FR 45371 - Rules in the 904-909.75 and 919.75-928 MHz Bands
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      Final rule.
      Effective Date: September 4, 2014.
      47 CFR Part 90

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Title 47 published on 2013-10-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 47 CFR 90 after this date.

  • 2014-08-06; vol. 79 # 151 - Wednesday, August 6, 2014
    1. 79 FR 45752 - Commission Seeks Comment on Shared Commercial Operations in the 3550-3650 MHz Band; Extension of Reply Comment Period
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      Proposed rule; extension of reply comment period.
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      47 CFR Parts 1, 2, 90, 95, and 96