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Re: [TowerTalk] ground plane problem help needed

To: Jim W7RY <jimw7ry@gmail.com>
Subject: Re: [TowerTalk] ground plane problem help needed
From: Jim Rhodes <jimk0xu@gmail.com>
Reply-to: jim@rhodesend.net
Date: Mon, 8 Aug 2022 15:01:09 -0500
List-post: <mailto:towertalk@contesting.com>
The antenna I modified did happen to be made by HyGain, if I remember
correctly.  Someone gifted it to me when I lived in Lincoln when I was in
school.  It was a long sucker, 5/8 wave on 11 meters.  First used it pretty
much stock on 10 meters when first licensed, but decided there was more
action on 20 so I shortened it to a 1/4 wave on 20.  There was a
transformer in the base to match the impedance of the 5/8 wave, so the
first thing I did was to remove it. Was only a round piece of pc board with
a spiral etched on it about an inch in diameter.  They were only built to
handle less than 20 watts.

On Mon, Aug 8, 2022 at 2:45 PM Jim W7RY <jimw7ry@gmail.com> wrote:

> As I said before. It's a choke.
>
> To provide a DC path to ground for static.
>
> 73, Jim. W7RY
>
> On Mon, Aug 8, 2022, 2:05 PM Gene Smar via TowerTalk <
> towertalk@contesting.com> wrote:
>
> >  Jim WA7DUY:
> >      Are you attempting to get a ground-plane vertical operating as an
> > elevated 1/4WL antenna using that base?  Or are you ground-mounting the
> 20M
> > element using the base just to hold the element onto a ground stake?
> > Answering those questions will clarify for us what you're attempting to
> do.
> >      I have a similar 11M GP antenna from Radio Shack that I cut down by
> > 11 inches (radials, too) to operate on 10M back in the late 70s.  I no
> > longer use it but it was easily found in my garage today.  I just now
> > measured the DC resistance of the base connections.  The SO-239 center
> pin
> > to insulator set screw measures zero Ohms (as it should) on my el cheapo
> > VOM; it measures about an Ohm between the SO-239 threads and the set
> > screw.  So there is something there between the center conductor and the
> > mounting base; not sure what it is, though.
> >
> >
> > 73 deGene Smar  AD3F
> >
> > -----Original Message-----
> > From: Jim Pruitt <jpruitt67@gmail.com>
> > To: towertalk@contesting.com
> > Sent: Mon, Aug 8, 2022 1:41 pm
> > Subject: Re: [TowerTalk] ground plane problem help needed
> >
> > As near as I can tell these were not HyGain verticals.  The mount part
> > looks similar to them.  No, there is no choke anywhere.there is just the
> > black plastic insulator that the vertical part goes through at the top of
> > the bracket and another at bottom where the SO239 is located.
> >
> > Thank you
> > Jim Pruitt
> > WA7DUY
> >
> > On Mon, Aug 8, 2022, 4:32 AM Jim W7RY <jimw7ry@gmail.com> wrote:
> >
> > > Is there a choke between the ground plane and the center conductor?
> > > An ohm meter will confirm.
> > > Hygain was famous for that.
> > >
> > > 73, Jim w7ry
> > >
> > > On Mon, Aug 8, 2022, 12:26 AM Jim Pruitt <jpruitt67@gmail.com> wrote:
> > >
> > >> About 4 years ago I picked up 2 bottom sections of what I think were
> 11
> > >> meter ground planes.  The section looks like the bottom section for a
> > >> HyGain 18AVQ vertical or similar. The only difference is the mounting
> > >> flange has a plate that holds what looks like about ½" diameter ground
> > >> radials.  The issue I am having is that I used that mounting section
> to
> > >> make a 20 meter vertical.  Easy enough, right? WRONG.  I used mating
> > >> tubes to make the ¼ wave 20 meter vertical but it resonated at...ready
> > >> for this.... 39mhz!  Then I grabbed the second one and used it.  Now
> it
> > >> resonates at 13.5mhz but shortening the vertical does not bring the
> > >> frequency up.  I am wondering if perhaps someone (CBer maybe) ran way
> > >> too much power through them and broke down the dialectic of the
> plastic
> > >> (or whatever that is) insulator that isolates the vertical from the
> > >> mounting bracket and ground.  That is the only explanation I can come
> up
> > >> with as to why it is so far off.
> > >>
> > >> Does anyone have any suggestions as to how to fix the problem?
> > >>
> > >> Thank you.
> > >>
> > >> Jim Pruitt
> > >> WA7DUY
> > >> _______________________________________________
> > >>
> > >>
> > >>
> > >> _______________________________________________
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> > >> TowerTalk@contesting.com
> > >> http://lists.contesting.com/mailman/listinfo/towertalk
> > >>
> > >
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-- 
Jim K0XU
jim@rhodesend.net
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