SWR, or Standing Wave Ratio, is a measure of how well your CB radio antenna is matched to the transmission line and the radio itself. A lower SWR value indicates a better match and more efficient transmission.
For a CB radio system, the ideal SWR reading is 1:1 (SWR of 1). However, achieving a perfect 1:1 SWR can be difficult in practice. Generally, a SWR reading of 1.5:1 or lower is considered acceptable and indicates a well-matched antenna system.
To measure SWR, you will need an SWR meter. Follow the instructions provided with the meter, but here is a general process:
- Ensure that the antenna system is properly installed, with the antenna mounted securely and the coaxial cable properly connected to the radio.
- Set the CB radio to channel 1.
- Connect the SWR meter in line between the radio and the antenna.
- Transmit a signal by keying the microphone and hold the transmission.
- Observe the SWR reading on the meter. The meter will indicate the forward power (FWD) and reflected power (REF).
- Adjust the antenna's length or position as needed to achieve the lowest SWR reading possible. This may involve adjusting the antenna's whip length or using an antenna tuner if available.
Remember to perform the SWR measurement and adjustment with the engine off to avoid interference from the vehicle's electrical system.
If you are unsure or uncomfortable with adjusting the antenna or measuring SWR yourself, it is recommended to seek assistance from a knowledgeable CB radio technician or an experienced user who can help you properly set up and optimize your CB radio system.