[TenTec] Model 963 questions

[Richards]

Thanks for the quick feed back.    Some comments while I try what
you suggest:

  1)   My bad.  Apparently, I was not clear in my first post...
	the hash shows	up in the middle of the AM Broadcast
	Band at  0.850 MHz, or 850 KHz  - MW and not UHF - although
	I do not think this changes much of what you said.   Oops.
	Also, the hash is being heard on my Omni VII... sorry I was
	not clear and sparked a short detour.

2)    I can try replacing the switch, but I can also live without
	the orange pilot light if that would be an easy solution.
	Do you think the light can be extinguished and still operate
	the switch?   That would be one way to tell if the neon
	pilot light is causing any of the hash.

3)    I did not mention it, but YES, I did try plugging it into other
	outlets, on different AC circuits, all with the same result.
	

4)  I put ferrite beads on the AC power cable, but may try them
	on the DC leads as you suggest...  Hmmm....

5)   I have a couple of hospital grade heavy duty AC isolation
	transformers formerly employed in my days as an avid
	SWL.   They never made much difference in my setup,
	but maybe one of them will find a use today.

I understand switching supplies are inherently noisy, but I have never 
noticed any noise or problems from this one before.   It came with my 
Omni VII and seemed to be totally filtered and quiet.  Only now after a 
couple of years, am I seeing any issues.  I like it because it is so 
much lighter than my other RS-35S, and the heavier Astron linear type 
supplies produce a barely audible Huuummmmm I would like to live 
without, so having two of them on the desk might be more hummmmm than I 
like.

Thanks for the input !!

------------------
Happy Trails.
=======================  Richards / K8JHR  =========================

On 9/20/2011 16:49, Stuart Rohre wrote:
> The flickering pilot light makes me wonder if it is a neon lamp in an
> off on switch?

> only recourse is to replace the switch if the lamp is non removable.

You could try
> putting the switcher power supply on a different AC circuit from the
> radio.  Or, if you can find a very good AC input side filter, one that
> filters both hot and neutral sides of the AC line, that might introduce
> another 20 dB of loss at HF/UHF, and keep the 850 MHz bottled up inside
> the switcher. Also check that the covers are on tight, if a metal box,
> and paint is not compromising the grounding of overlapping joints.
> Ferrite beads might be tried on the output DC leads, if not already
> there. (Internally).

> Most of the ham market switchers, if filtered, are mainly suppressed in
> the HF ham bands.  It is really hard to build one that is bulletproof,
> however.
>
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