[Elecraft] k3 50Hz background noise

[Dave Hachadorian]

Make sure there is a ground wire on the rotator controller. 
That knocked the hum way down here. I had the same problem 
with my TS-850's, and there were no audio input transformers 
in that rig.

Dave Hachadorian, K6LL
Yuma, AZ

----- Original Message ----- 
From: "Igor Sokolov" <ua9cdc at gmail.com>
Cc: "Elecraft" <Elecraft at mailman.qth.net>
Sent: Wednesday, October 21, 2009 4:35 PM
Subject: [Elecraft] k3 50Hz background noise


> My friend, K3 user is getting ready for CQWW SSB. In his 
> installation the
> rotator control box that has pretty large transformer 
> inside.  The box is
> only few inches away from one of the two K3s  and cannot 
> be moved. He has
> discovered that magnetic field created by this transformer 
> interacts with
> the AF transformer (Line in) in K3. The indused 50Hz noise 
> is only 20db down
> from the audio signal. The noise is gone when line in is 
> switched off in the
> menu but that leaves him without voice keyer which is 
> tough to be deprived
> of in 48 hours SSB contest. Has anybody found a solution 
> yet. He now thinks
> of taking the transformers out of the radio an bypassing 
> them. He thinks
> that the problem roots to the fact that the K3 cabinet is 
> made of aluminum.
>
> 73, Igor UA9CDC
>
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