Re: [Elecraft] K3: transmitted RF feedback with condenser mics?

Posted by W6ODJ on Jan 25, 2010; 5:14pm
URL: http://elecraft.85.s1.nabble.com/K3-transmitted-RF-feedback-with-condenser-mics-tp4450419p4455237.html


From: Oliver Johns <[hidden email]>
Date: 25 January 2010 09:12:00 PST
To: Brian Machesney <[hidden email]>
Cc: Oliver Johns <[hidden email]>
Subject: Re: [Elecraft] K3: transmitted RF feedback with condenser mics?

Try putting a snap-on ferrite bead ON the actual boom of the electret headset microphone.  Put it right at the end, just before the microphone bulb.  Maybe the RF is getting into the electret or its FET and is being rectified there.

Oliver Johns
W6ODJ


On 24 Jan 2010, at 11:53, Brian Machesney wrote:

> I am getting transmitted RF feedback into the K3 when running high power
> with a headset that uses a condenser element. With an otherwise identical
> setup, I don't have any problems with either of my two headsets that have
> dynamic mic elements, using either the front- or the rear-panel mic jacks.
>
> I hear the distortion in the K3's own monitor, but I have confirmed the
> distortion using my K2 as a second receiver (1" wire in the ANT jack, RF
> gain near zero, ATT on to prevent front-end overload) and with on-the-air
> tests with stations hundreds to thousands of miles away.
>
> The problem headset is designed for aviation use and, as far as I can tell,
> uses a shielded mic cable.
>
> Has anyone else had and resolved this problem?
>
> --
> 73 -- Brian -- K1LI
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