The effective radiated power of central office and rural subscriber station transmitters used in basic exchange telephone radio systems must not exceed the limits in this section.

(a) Maximum ERP. The effective radiated power (ERP) of central office and rural subscriber station transmitters in BETRS must not exceed the applicable limits in this paragraph under any circumstances.

(b) Height-power limit. The ERP of central office stations in BETRS must not exceed the amount calculated as follows:

ERPw = 557,418 ÷ hm2 where ERPw is the effective radiated power in Watts hm is the average (eight cardinal radial) antenna height above average terrain in meters