[TenTec] Re: Astron Power Supplies

[Mike Hyder -N4NT-]

Stuart, I suspected as much.  A vague reference to the whole book.  Find
something in it that applies to this particular sort of problem and then
send me the cite.  You didn't answer my question about whether I ought to go
in and isolate the DC outputs of my Ten-Tec supplies from the cabinets,
either.  Wonder how many Ten-Tec supplies work without all the problems
which you associate with "ground loops."  To my knowledge, no manufacturer
of amateur gear makes supplies with a floating output.  By the way, "ground
loops" are sort of like alchemy, the talk of people who believe radio works
with smoke and mirrors.  Those you might get by grounding a well engineered
supply (which the Astron is not, in my opinion) to the rig via a bus, in
addition to the DC cable, are non-existant.  You are borrowing trouble and
inviting others to do the same.

I can tell you that I had an Astron VS35 powering a Yaesu FT-757 for the
three weeks before I drop-kicked the rig out of the shack window.  Until I
grounded the negative post to the cabinet, RF from the rig would affect the
voltage output drastically.  My antenna was a TH-6 at 70 feet fed with good
coax.  The real thing I wonder is why you would discourage that fellow from
trying the fix.  He was looking for something to try.  You poo-pooed the
idea.  You were wrong in theory, wrong in practice, and wrong to try to
dissuade the fellow from trying something that will probably fix his
problem.  The only other things I saw on the reflector were "put the supply
on the other side" or "change the length of your DC cable," all crap -- as
if all this is mysterious.  Look at the diagram of the supply and if you are
as experienced as you claim, you will see right off the problem with the
voltage regulator circuitry when the supply is used in an RF environment and
the negative post is not connected to the cabinet.

So the proof is in the pudding.  Let him try the fix and see if it cures his
trouble.  If the trouble is the Astron going out of regulation, then this
will either fix his problem or it won't.  It won't cost him a nickel to try
it.  His reports back to the reflector will serve to alert others to a
possible fix.

Once again, I suggest you look at the schematic of the Astron.  A man with
your experience should see the problem with the Astron's right off.

73, Mike N4NT@chartertn.net

----- Original Message -----
From: "Stuart Rohre" <rohre@arlut.utexas.edu>
To: "Mike Hyder -N4NT-" <N4NT@chartertn.net>
Sent: Tuesday, October 23, 2001 7:17 PM
Subject: Re: [TenTec] Re: Astron Power Supplies


> Mike,
> The nature of Ralph's book is that you really need the whole thing.
> It is not all that long, being about the size of a paperback and about 1/2
> inch thick.
>
> However, it is a systematic and comprehensive overview of the whole
> grounding methodology, step by step.  I also went up to ARRL web just now,
> looking for any useful TIS papers I could point out, but had some log in
> problems since some of the QST papers are members only, and my password
was
> not up to date.
>
> Engineering libraries of universities should have Ralph's book, I checked
> mine back into our tech library, and I will see if it is available so that
I
> might give you the publisher info.
> 73,
> Stuart
>
>
>