[Kenwood] Astron RS-35M Radiated Noise

[peter markavage]

I have an Astron VS-50 here that is plagued by audible hum. Tightening of
the transformer screws did not alleviate the problem. I have wooden
shelves on top of the operating position table with the power supply on
the first shelf. It was so bad that the hum would propagate through the
shelves and get picked up by the desk mike and into the audio. Lift the
desk mike off the table and hum in the audio went away. My simple
solution was to put one of those foam mouse pads under the base of the
microphone. Hum in audio went away. Further, I put two foam mouse pads (I
didn't have one big enough to cover the area under the feet) under the
feet of the power supply to further damp the power supply hum. Now you
have to put your ear to the power supply to hear the hum.

Maybe not an answer to your specific problem but might help others
plagued with propagated power supply hum.

Pete, wa2cwa


On Sun, 16 Jan 2005 22:15:28 -0500 "rob" <rob at gallagher.net> writes:
> Anyone have a problem with the PS generating 60Hz radiated noise when 
> even
> minimal load(<2A) is applied.  It maintains regulation and ripple 
> is
> <50mvp-p.
> 
> I noticed this when monitoring 160m.   Then got the HT Kenwood 
> TH-F6a and
> tracked it down to the RS-35M.  No noise without load. Went from an 
> S-2
> noise floor to S-7 when in receive with a IC-746Pro and S-9 when
> transmitting 100Watts.
> 
> I also have a RS-35(non M) and it does not do this.  I interchanged 
> will
> socketed and screwed in devices but this did not improve the noise.
> 
> I suspect eddy currents in the transformer but just a guess now.
> 
> Ideas?
> 
> Tnx,
> 
> Rob - W3RG