UpTheTower@aol.com wrote:
>
> ---------------------
> Forwarded message:
> From: owner-towertalk@contesting.com
> To: owner-towertalk@contesting.com
To: <towertalk@contesting.com>
> Date: 97-05-16 05:21:22 EDT
>
> >From k7lxc Fri May 16 01:19:13 1997
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To: <towertalk@contesting.com>
> Date: Thu, 15 May 1997 18:49:35 -0700
> From: George Worth <gworth@ibm.net> (by way of dick@merlin.libelle.com (Dick
> Flanagan))
> To: rptrown@clarc.org, towertalk@contesting.com
> Subject: HELP: Rpt noise when windy!!
> Organization: Libelle Productions, Inc., Minden, Nevada USA
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> Al, I posted this on rec.radio.amateur.homebrew,misc and equip.
> Chupa Cabara
>
> Gentlemen,
> I have a question for anyone that may have experienced "crackling" noise
> on their VHF repeater when the wind is blowing. Here is the scenario.
> We were donated a spot on a wooden utily pole which sticks out of the
> ground (the earth here is rock with a couple inches of soil over it)
> about 85 ft. There are 4x4 wooden cross arm systems at a couple places
> on the pole. At each cross arm there are 2) 4x4's bolted through the
> pole with u-clamps at the ends. This is where the 2" pipes are clamped to
> 4x4's for the antenna mounting. All 4 UHF machines work well. No noise.
> The VHF one does not. If the wind blows, the noise gets so strong it
> kicks incoming signals right out of the repeater. We have checked all
> antenna and feedline connections. They are good. What we did find was
> that if we wiggle or touch (with metal object) any (!!!ANY!!!) metal
> parts on the 4x4 support angle irons, 6 ga lightning ground wire which
> runs from the antenna mounts to central pole wire and down, pipes,
> anything metal at all, the noise is horrendous. What we suspect is that
> due to lack of RF ground, there is a pretty decent RF voltage/current,
> whatever, flowing or present on all the metal parts up there. If every
> piece of metal was bonded together and we nail copper flashing to the
> pole to connect RF grounds to, would this get rid of the dreaded
> "cracklies"?? How can we get a decent RF ground for VHF in the earth
> on top of this mountain? Any ideas would be more than greatly
> appreciated. Thanks for your help.
>
> George
>
> gworth@ibm.net
I think you have correctly diagnosed the problem/and a possible cure.
What type of antenna are you using? Perhaps a decoupling skirt might
help.
--
Joe Leikhim
Jleikhim@nettally.com
"tv dinner by the pool,
i'm so glad i finished school" -F.Zappa 1967
"The Revolution will NOT be televised" -Gil Scott Heron
--
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