47 CFR 90.729 - Limitations on power and antenna height.
(a) The permissible effective radiated power (ERP) with respect to antenna heights for land mobile, paging, or fixed stations transmitting on frequencies in the 220-221 MHz band shall be determined from the following Table. These are maximum values and applicants are required to justify power levels requested.
ERP vs. Antenna Height Table 2
|Antenna height above average terrain (HAAT), meters||Effective radiated power, watts 1|
|Up to 150||500|
|150 to 225||250|
|225 to 300||125|
|300 to 450||60|
|450 to 600||30|
|600 to 750||20|
|750 to 900||15|
|900 to 1050||10|
1 Transmitter PEP shall be used to determine ERP.
2 These power levels apply to stations used for land mobile, paging, and fixed operations.
(b) The maximum permissible ERP for mobile units is 50 watts. Portable units are considered as mobile units. Licensees operating fixed stations or paging base stations transmitting on frequencies in the 221-222 MHz band may not operate such fixed stations or paging base stations at power levels greater than 50 watts ERP, and may not transmit from antennas that are higher than 7 meters above average terrain, except that transmissions from antennas that are higher than 7 meters above average terrain will be permitted if the effective radiated power of such transmissions is reduced below 50 watts ERP by 20 log10(h/7) dB, where h is the height above average terrain (HAAT), in meters.
(c) Base station and fixed station transmissions on base station transmit Channels 196-200 are limited to 2 watts ERP and a maximum antenna HAAT of 6.1 meters (20 ft). Licensees authorized on these channels may operate at power levels above 2 watts ERP or with a maximum antenna HAAT greater than 6.1 meters (20 ft) if:
(1) They obtain the concurrence of all Phase I and Phase II licensees with base stations or fixed stations receiving on base station receive Channels 1-40 and located within 6 km of their base station or fixed station; and