See <http://www.qsl.net/k2vco/sniffer/rfsniffer.html>. This device can be calibrated, but for most purposes a relative indication is adequate. On 2/21/2014 6:25 AM, Mark Beckwith wrote: > I don't know how to measure current in radials -- 73, Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/