You need to read and be familiar with 47 CFR Part 95, which is the
FCC rules for
CB and other personal radio services. Specifically paragraph 95.408(d):
(d) If your
CB station is located near an airport, and if your antenna structure is more than 6.1 meters (20 feet) high, you may have to obey additional restrictions. The highest point of your antenna must not exceed one meter above the airport elevation for every hundred
meters of distance from the nearest point of the nearest airport runway.
Differences in ground elevation between your antenna and the airport runway may complicate this formula. If your
CB station is near an airport, you may contact the nearest
FCC field office for a worksheet to help you figure the maximum allowable height of your antenna. Consult part 17 of the
FCC's Rules for more information.
Warning: Installation and removal of
CB station antennas near powerlines is dangerous. For your safety, follow the installation directions included with your antenna.