What is SWR?

The term “SWR” means standing wave ratio. A “SWR” meter is used to measure how well the transmit power signal emitted from a transceiver (radio) is traveling through the antenna system into the atmosphere. Checking and setting the antenna is critical to overall performance of transceiver (radio). During installation of a Business Band, CB, Ham or Marine radio or installing a new antenna the SWR must checked to ensure the transmit power coming from the radio is traveling through the antenna system correctly. A poor performing antenna system significantly reduces (transmit & receive) range and can damage the transceiver (radio). When the signal does not travel through the antenna system correctly the transmit power is reflected back into the transceiver which causes reduced range and damage to the internal parts.
SWR MeterAn “SWR” (standing wave) meter is used in conjunction with a short coax cable (RG58AU with 2- PL259’s) between the radio and antenna system to perform the test. A poor reading on the “SWR” meter will indicate that there is a problem with installation of your radio or antenna system. When the “SWR” test is performed the meter will indicate if your antenna is working properly and provide a reading so the antenna can be adjusted for optimum performance. The meter will also indicate if there is a poor or bad (radio/antenna) ground, improperly set antenna, poor antenna location or coax obstruction or short. A poor test reading on the “SWR” meter (in the red) indicates that there is a significant problem with the antenna system or a bad radio ground that requires correcting or adjusting prior to using the radio. DO NOT OPERATE THE RADIO UNTIL A GOOD “SWR” CAN BE ACHIEVED.

CB radio “SWR” meters (26-27 MHz) are fairly inexpensive however, meters to check other radio frequencies can be expensive. Make sure to purchase a “SWR” meter that will test the frequency range your radio operates in. Example: CB radios operate on 26-27 MHz a Marine radio operates on 156-164 MHz. A short coaxial cable with 2) PL259 connectors will also be required in conjunction with the “SWR” meter to perform the test. When purchasing a “SWR” meter you will need to order a coaxial cable separately if it is not included with meter. Checking and setting the “SWR” on all radio applications is the most important step in obtaining the best performance possible. When testing and adjusting the antenna make sure to check “SWR” on the lowest channel and the highest channel. By adjusting and setting the “SWR” on the entire bandwidth (high and low channels) it will ensure optimum performance on all of your radio channels. The radio will receive and transmit well with a good “SWR” reading of 2.5 or less across all channels. The lower the “SWR” reading the better your radio will perform.