Human Exposure to RF Fields from Vehicle-Mounted Antennas

Vehicle-mounted antennas used for wireless communications normally operate at a power level of three watts or less. These wireless antennas are typically mounted on the roof, trunk or rear window of a car or truck.

Studies show that, in order to be exposed to RF levels that approach the safety limits adopted by the FCC, it would be necessary to remain very close to a vehicle-mounted wireless antenna for a significant amount of time. Studies have also shown that the metal body of the vehicle can effectively shield occupants. Proper installation of a vehicle-mounted antenna to maximize this shielding effect is a good way to minimize exposure. Some companies recommend that antennas be installed either in the center of the roof or center of the trunk of a vehicle. In response to concerns expressed over the commonly used rear-window mounted wireless antennas, a minimum separation distance of 1-2 feet has been suggested as a way to minimize exposure to vehicle occupants.

From data gathered to date, properly-installed, vehicle-mounted, personal wireless antennas using up to three watts of power result in maximum exposure levels in or near the vehicle that are typically well below the FCC’s safety limits, assuming that the transmitting antenna is 6 inches or more from vehicle occupants.

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Human Exposure to RF Fields from Vehicle-Mounted Antennas (pdf)