VINTAGE Jewell Milliamperes Thermocouple Type RF Radio Frequency Meter Gauge NoVINTAGE Jewell Milliamperes Thermocouple Type RF Radio Frequency Meter Gauge No vintage Jewell Electrical Instrument Company Pattern No. 54 thermocouple type RF milliamperes meter galvanometer. This specific style of "current squared" meter was designed for measuring alternating currents (AC) at radio frequencies (RF) using a heating element and thermocouple principle, commonly used in early radio equipment and test sets This item is in used, vintage