[TowerTalk] Grounding Feedlines

[Jerry Keller]

If he's non-tech, he won't notice the nice ground you install at the duplexer. Just do it and don't
tell him. It's a mitzvah.... a good deed.   73,  Jerry K3BZ

----- Original Message ----- 
From: "Roger Parsons" <ve3zi at yahoo.com>
To: <towertalk at contesting.com>
Sent: Monday, September 27, 2004 8:50 AM
Subject: [TowerTalk] Grounding Feedlines


> An anecdote:
>
> Yesterday several of us were working at my (borrowed)
> commercial tower putting up my new 160m antenna. The
> tower owner has a VHF 10C4 at the very top of the
> tower (325') fed with Heliax. As the brave, strong
> tower climbing guy went up he cut the tie-wraps round
> some of the coaxes going up the tower. Suddenly the
> commercial radio in the hut started relaying the local
> AM broadcast station, which is only about 2km away and
> has a field strength which can undoubtedly be measured
> in volts. Panic!
>
> To cut a long story short we found that grounding the
> coax outer where it entered the duplexer cured the
> problem. Further investigation showed that the only
> ground on the feedline was through the radio/power
> ground, EXCEPT that the Heliax/RG213 transition point
> connectors just happened to touch a grounded conduit.
> Our moving the coax had slightly dislodged it. A
> tie-wrap 'cured' it.
>
> This is a commercial installation. NO ground on the
> coax at the base of the tower. NO lightning surge
> suppression whatsoever. The system has worked entirely
> due to God's good graces.
>
> I'm not quite sure what to do here. I could obviously
> put a proper coax ground and lightning suppressor at
> the base of the tower. But then I'm interfering with a
> commercial installation. If I do nothing, the fault
> will probably reappear at some point. The tower owner
> is completely non-technical and I fear if I mention it
> to him he will assume it is because of my equipment.
>
> Thoughts anyone?
>
> 73 Roger
> VE3ZI
>
>
>
>
>
>
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