[Elecraft] Hum on 15 Meters CW

[Don Wilhelm]

Mitch,

Are you certain it is coming from the K3?  I have conditions like that 
on some bands at my workbench where I have amplifier computer speakers.  
Since it is not constant, and I don't operate from there, I ignore it, 
but I would chase it down and kill it if it were at the operating position.

73,
Don W3FPR

On 11/12/2011 6:04 PM, WD0ECO wrote:
> I'm hearing a vibrating humming noise from my K3 when keying CW on 15 meters.
>
> It is only on 15 meters and only with my beam antenna - not heard on the
> dipole or vertical.
>
> SWR is 1.6 with K3 tuner bypassed (LP-100A meter) and 1.1 with tuner on and
> according to K3 meter.  Tried different keys - still hum.
>
> The hum is not heard under 50 watts but gets progressively louder from 50 to
> 100 watts.
>
> I don't notice the hum on 15 meters SSB via mic.
>
> This just started happening.  Any ideas?  It doesn't appear to affect output
> or have high SWR.  Is it hurting anything???
>
> 73, Mitch
>