first consider FCC
Rules Part 95.
§ 95.408 (CB
Rule 8) How high may I put my antenna?
(a) Antenna means the radiating system (for transmitting, receiving or both) and the structure holding it up (tower, pole or mast). It also means everything else attached to the radiating
system and the structure.
(b) If your antenna is mounted on a hand-held portable unit, none of the following limitations apply.
(c) If your antenna is installed at a fixed location, it (whether receiving, transmitting or both) must comply with either one of the following:
(1) The highest point must not be more than 6.10 meters (20 feet) higher than the highest point of the building or tree on which it is mounted; or
(2) The highest point must not be more than 18.3 meters (60 feet) above the ground.
(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.