Here's a handy little RF sensing switch. This is the unit you need when adding a preamp or power amp in line with an existing antenna. It senses the RF power and closes an on board DPDT relay which can be used to automatically switch in your added power amp or preamp-mast mounted for best performance! The relay is good up to UHF and can handle 100 watts or 1 amp DC. Many folks use one of these 'lifesavers' in front of their expensive scope, signal generator, service monitor or spectrum analyzer. If you accidentally transmit into it, the RFS-1 will safely bypass the power away from the test gear, thus saving an expensive repair!

Specifications: Runs on 10-15 VDC, works with any type radio, very sensitive, matches Ramsey PA-1, ideal for power amps & preamps.