[TenTec] Orion and RF Feedback

[Gary Hoffman]

This is correct.....a quarter wave will be a bad thing.  Either you have to
be significantly less than a quarter wave, or, tuned at a half wave (which
will reflect the low impedance of the ground into the shack).  That gives
you a low impedance in the shack.  That will ground it.  Of course, that
half wave may radiate some energy also, kind of like certain types of
antennas, you will then have two radiating segments perhaps.  This is
generally not a bad thing.

If you have half waves on every band, then you won't have any band where you
don't have a low impedance in the shack.  Of course, once the frequency gets
low enough, then you can have a wire significantly less than a quarter wave,
and no issues on that band.

You can also use the quarter wave counterpoise wires like some people do.
This will give you a low impedance point also, but as is well known, they
have their own sets of problems.

Basically, between shielding, grounding, and especially isolating of every
single wire into and out of every box, you ought to be able to beat the
problem down.

73 de Gary, AA2IZ


----- Original Message ----- 
From: <K4IA at aol.com>
To: <tentec at contesting.com>
Sent: Sunday, October 15, 2006 3:19 PM
Subject: Re: [TenTec] Orion and RF Feedback


>
> In a message dated 10/15/2006 12:49:55 P.M. Eastern Standard Time,
> john at gotwals.com writes:
>
> run a  wire down a story and a half to a ground rod
>
>
> As the Radioworks article points out, that is an "unground" and may be the
> worst thing you can do.  The story and a half is almost exactly a quarter
wave
> on 20 meters meaning you will see a high impendence at the radio end.
Other
> bands will also offer significant mismatch ca suing the energy to stay on
> your rig.
>
> When I had a second floor shack I used no ground at all.  I ran my  coax
away
> from the antenna at a right angle or straight down to the ground, then
back
> up again at the shack end to minimize interaction with the antenna  field.
I
> also used a choke balun at the radio end.  That cured my  problems.
>
> k4ia
> Craig  "Buck"
> Fredericksburg, Virginia USA
>
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>