Why is SWR important?
SWR readings typically have a range of about 1 – 10. The lower the number, the better the antenna is working. As the SWR climbs, both transmit and receive range will drop. An SWR of 1 is perfect, but it is not possible to get a perfect reading on all 40 channels. When an antenna is properly adjusted, the SWR will be highest on channels 1 and 40, and lowest on channel 19. Optimum performance is attained by adjusting the antenna so that the SWR is the same on channels 1 and 40. This gives the best performance throughout all 40 channels. The SWR reading must never exceed 3, otherwise the transmitter in the CB radio can overheat and eventually fail. Excessively high SWR can also cause other problems such as a squealing noise, or can cause interference with other electronic devices in the vehicle. An SWR of 2 or less is very good, and an SWR of 1.5 or less is excellent.
