The Radio Shack standing wave ratio meter (SWR) is used to check the standing wave of a CB radio or a ham radio. The meter measures the SWR during transmission. If the standing wave is too high, the transmission on the CB or shortwave radio is inefficient. The acceptable standing wave reading should be 1.0 to 1.5 for excellent transmission, 1.5 to 2.0 for good transmission and 2.0 to 3.0 for acceptable transmission. Anything above 3.0 is inefficient and must be corrected in order to use the radio without damaging the unit.
