VINTAGE SWR Instrument and Field Strength Indicator Model P5453

VINTAGE SWR Instrument and Field Strength Indicator Model P5453. Excellent condition. Comes from a smoke free home. An SWR instrument measures the efficiency of a radio antenna system by determining the Standing Wave Ratio (SWR). A field strength indicator, on the other hand, measures the relative power of the signal being radiated by the antenna. These two functions are often combined into a single, multi-purpose meter for convenience.