[CQ-Contest] SO2R & ground loops?

[w9wi at bellsouth.net]

At N4ZZ, we have two FT1000MP's wired to a headphone switch which allows
"splitting" the phones or feeding either radio to both sides.  When both
headphone plugs are connected, Don is hearing a high pitched "whine" or
"buzz".  It's not enormously loud (I didn't hear it when I operated the
CW Sprint there) but it bothers Don on a quiet band.  The noise goes
away when either headphone plug is disconnected.

Of course, the two rigs share a ground, as well as being mutually
grounded through the antenna connections (Six-Pak), the power supply for
the band decoders, and the computer, not to mention the safety ground on
the AC power cables.  

Has anyone else run into this problem?  Am I on the right track to try
to come up with a 1:1 transformer to isolate the headphone grounds?
-- 
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://personal.bellsouth.net/~w9wi



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