Clamp-on RF current meters - a question for Ian and others..

Posted by VK7JB on Nov 04, 2011; 3:12am
URL: http://elecraft.85.s1.nabble.com/Clamp-on-RF-current-meters-a-question-for-Ian-and-others-tp6961533.html

Hi All,

I've been reading the discussions about RF and common mode current and using a clamp-on RF current meter to sniff out common mode current in the shack.  I've checked the calibration of my MFJ 854 and am surprised that it's calibrated quite well:  I measure 1A of current measured running 50W into a 50ohm dummy load.

So, here's my question:  how much common mode current is considered "acceptable"?  This meter measures down to a few milliamps.  Is it an impossible/futile goal to try to eliminate any stray CMC completely?  When should you call it quits and accept what you find?

Just curious, because the only CMC I can measure in my shack is about 10mA measured at the coax connector on the back of one of my rigs while tuning up with 10W output.  

Interesting discussion, because I'd never thought of quantifying CMC before.

73,
John
VK7JB