Goto Section: 90.307 | 90.311 | Table of Contents
FCC 90.309
Revised as of October 1, 2005
Goto Year:2004 |
2006
Sec. 90.309 Tables and figures.
(a) Directions for using the tables. (1) Using the method specified in
Sec. 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 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 Prote
ction) Maximum Effective Radiated Power (ERP) \1\
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Antenna height in meters (feet) (AAT)
--------------------------
-------------------------------------------------------------------------
Distance in kilometers (miles): \2\ 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (1
50) 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.
Table B_Base Station_Cochannel Frequencies (40 dB Prote
ction) Maximum Effective Radiated Power (ERP) \1\
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Antenna height in meters (feet) (AAT)
--------------------------
-------------------------------------------------------------------------
Distance in kilometers (miles): \2\ 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (1
50) 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 Effective Radiated Power (ERP) \1\
-------------------------------------------------------------------------------
-------------------------------------------------------------------------
Antenna height in meters (feet) (AAT)
--------------------------
-------------------------------------------------------------------------
Distance in kilometers (miles): 2,3 30.5
91.5 106 122 137 152.5
15 (50) (100) 45 (1
50) 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 asso
ciated with the base station. See sec. 90.307(d).
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 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.
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(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]
Goto Section: 90.307 | 90.311
Goto Year: 2004 |
2006
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