Magnet mount CB antennas are used on vehicles with metal surfaces. The antennas have a magnetic base, antenna and coaxial to connect the antenna to the CB inside of the vehicle. Once the antenna is mounted and the coax cable is connected, you will need to adjust the antenna to lower or raise the standing wave reading (SWR) before using the CB for communication. If the SWR is not below 2.0 (preferably 1.5), damage to the radio is possible as well as limited transmission.
Instructions
1. Attach the short jumper coaxial cable that comes with the SWR meter to the back of the CB where it says, "Ant." Connect the other end of the jumper coaxial cable to the "Ant Out" or "Transmit" on the SWR meter. Connect the antenna to the SWR meter where it says," Ant In."
2. Turn the channel knob to channel 1 on the CB. Move the switch on the SWR meter to "FWD."
3. Press the transmit key on the side of the microphone. Hold the key in and use the knob labeled "Adjust" to move the needle to the "Set" position. Keep holding in the transmit key and move the switch on the meter to "REF." Note the reading and release the transmit key.
4. Repeat steps 2 and 3 substituting channel 1 with channel 19 and then channel 40. Note the SWR on each of the three channels.
5. Adjust the antenna by using the Allen wrench to loosen the Allen screw at the base of the antenna. If the standing wave is over 2.0 on channel 1, lengthen the antenna by pulling up on the antenna so it raises 1/8 inch. Tighten the allen screw. If the standing wave was over 2.0 on channel 40, lower the antenna 1/8 inch.
6. Recheck the standing wave following steps 2 and 3 on channels 1, 19 and 40. Adjust as needed following step 5 until you have a standing wave under 2.0.
Tags: standing wave, base antenna, channels Adjust, coaxial cable, jumper coaxial