Goto Section: 90.307 | 90.311 | Table of Contents
FCC 90.309
Revised as of
Goto Year:1996 |
1998
Sec. 90.309 Tables and figures.
(a) Directions for using the tables. (1) Using the method specified
in Sec. 73.611 or charts or maps of suitable scale, determine the
distances (i) between the proposed land mobile base station and the
protected cochannel television station and (ii) 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
cochannel 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.
[[Page 494]]
(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 km (2 mi) and 16 km (10 mi) 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 km (10 mi). The
radials should be drawn starting with true north. At least one radial
should be constructed in the direction of the nearest cochannel and
adjacent channel UHF television stations. The profile graph for each
radial shall be plotted by contour intervals of from 12.2 m (40 ft) to
30.5 m (100 ft) 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 m (200 ft) to 122 m (400 ft) 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 km (8-mile) distance between 3.2
km (2 mi) and 16 km (10 mi) 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. Geological Survey, may be utilized in lieu of maps, but the number
of data points must be equal to or exceed that special 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 E
ffective Radiated Power (ERP) \1\
------------------------------------------------------------------------------------------------
--------------------------------------------------------
Antenna hei
ght in meters (feet) (AAT)
-------------------------------------------
--------------------------------------------------------
Distance in kilometers (miles): \2\ 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (150) 61 (200) 76
(250) (300) (350) (400) (450) (500)
------------------------------------------------------------------------------------------------
--------------------------------------------------------
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
------------------------------------------------------------------------------------------------
--------------------------------------------------------
\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.
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Table B--Base Station--Cochannel Frequencies (40 dB Protection) Maximum E
ffective Radiated Power (ERP) \1\
------------------------------------------------------------------------------------------------
--------------------------------------------------------
Antenna hei
ght in meters (feet) (AAT)
-------------------------------------------
--------------------------------------------------------
Distance in kilometers (miles): \2\ 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (150) 61 (200) 76
(250) (300) (350) (400) (450) (500)
------------------------------------------------------------------------------------------------
--------------------------------------------------------
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 4(115).......................................... 1,000 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 ........ ........ ........ ........ ........
------------------------------------------------------------------------------------------------
--------------------------------------------------------
\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.
Table C--Mobile and Control Station--Distance Between Associated Base
Station and Protected Cochannel TV Station
[50 dB protection]
------------------------------------------------------------------------
Distance
Effective radiated power (watts) of -------------------------------
mobile unit and control station 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]
------------------------------------------------------------------------
Distance
Effective radiated power (watts) of -------------------------------
mobile unit and control station 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 Effecti
ve Radiated Power (ERP) \1\
------------------------------------------------------------------------------------------------
--------------------------------------------------------
Antenna hei
ght in meters (feet) (AAT)
-------------------------------------------
--------------------------------------------------------
Distance in kilometers (miles): 2,3 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (150) 61 (200) 76
(250) (300) (350) (400) (450) (500)
------------------------------------------------------------------------------------------------
--------------------------------------------------------
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
------------------------------------------------------------------------------------------------
--------------------------------------------------------
\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 b
ase station. See sec. 90.307(d).
Table ``F''--Decibel Reduction/Power Equivalents
------------------------------------------------------------------------
ERP
permitted
dB reduction below 1 kW (figures
rounded)
------------------------------------------------------------------------
1........................................................... 795
2........................................................... 630
3........................................................... 500
4........................................................... 400
5........................................................... 315
6........................................................... 250
7........................................................... 200
8........................................................... 160
9........................................................... 125
10.......................................................... 100
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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 Sec. 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 Sec. 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.
[[Page 497]]
[GRAPHIC] [TIFF OMITTED] TC02AP91.010
[[Page 498]]
[GRAPHIC] [TIFF OMITTED] TC02AP91.011
(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]
[[Page 499]]
Goto Section: 90.307 | 90.311
Goto Year: 1996 |
1998
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