3db Racing Antenna

3db Racing Antenna recommended when it can be mounted in the center of a flat roof, with no objects 18" in any direction. If you have a roof rack, light bar or need to mount somewhere other than the center of the roof, select the No Ground Plane Antenna. Frequency Range: 138-174mHz Please specify race channel in notes above or we will tune (cut) to mid (151.625) Cut Chart Frequency Whip Length 150 MHz 45 1/8" 151 MHz 44 3/8" 152 MHz 44 1/8" 153 MHz 43 3/4" 154 MHz 43 3/8" 155 MHz 42 7/8" 156 MHz 42 5/8" 157 MHz 42 1/4" 158 MHz 41 3/4" 159 MHz 41 1/4"   Mounting Instructions Mounting your antenna properly determines the range of your two-way radio. A metal roof with an antenna mounted in the center with no obstructions (roof rack, light bar) 18" in every direction provides the farthest range. Roof Racks - Mount the antenna at the highest point of the rack. Use a no ground plane antenna. No Roof - Pick a spot in the middle of the car. The intersection of two tubes can also act as a ground plane. Mounting the antenna to a corner triangle tab and using a no ground plane antenna will work best. Do not run radio coax and intercom helmet cables in the same wire loom. RF can bleed over when transmitting, putting noise into the system. Never run coax or power cables near MSD or igniton equipment. They create noise and if the coax is too close to the MSD, transmitting can even power the vehicle off! When tie wrapping the coax to the frame, do not crush the coax. If your coax looks flattened, kinked, frayed, or worn, replace it!