[RFI] Earth isolation

EDWARDS, EDDIE J eedwards at oppd.com
Thu Sep 9 09:48:49 EDT 2004


I think what Tom is saying is if you change the impedance of a
common-mode "Circuit" by adding an RF choke to the cable entrance,
current no longer flows at all so it doesn't have to go anywhere since
it no longer exists!  

The Common mode"circuit" without the choke has currents only because of
it's characteristic impedance without the choke; change that impedance
by adding the choke and the currents simply vanish.  No shunting needed.

If you place the choke on the AC mains ground you WILL create a change
of that circuit's characteristic impedance and it will no longer
function as the AC safety ground whenever you need it.  You also violate
the single point grounding principle since that circuit now sees other
grounds as lower impedances (like thru your equipment circuit boards or
through humans in some cases).  

73, de ed -K0iL

-----Original Message-----
From: rfi-bounces at contesting.com On Behalf Of Tom Rauch
The real cure is to stop it at the entrance to the shack,
not the power line exit!!!


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