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Re: [TowerTalk] Grounding Question

To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] Grounding Question
From: "K1TTT" <K1TTT@ARRL.NET>
Date: Sat, 26 Mar 2011 10:45:06 +0000
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Weatherproofing is easy and cheap... Go to local hardware store, buy a
couple of pounds of ductseal and some half decent electrical tape (not the
real expensive stuff for this).  Grab a big handful of the ductseal, mold it
around the joint to be protected, then apply a layer of tape around it to
protect it from the sun and keep it in place around the joint.  Cheap, works
fine, lasts a long time, much easier to remove than coax seal or dipped
rubber junk or self vulcanizing tape.


David Robbins K1TTT
e-mail: mailto:k1ttt@arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: K8RI on TT [mailto:k8ri-on-towertalk@tm.net] 
> Sent: Saturday, March 26, 2011 04:36
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Grounding Question
> 
> 
> On 3/25/2011 10:42 PM, Gene Smar wrote:
> > Roger:
> >
> >       I understand why you might think that weatherproofing 
> a ground clamp on
> > braided coax like RG-8/u might be tricky.  However, it can 
> be done if you
> > apply the proper materials.
> 
> I don't disagree with that, but I think the weatherproofing technique 
> may be a bit beyond many.
> In my case with a 100 foot tower and with grounding normally figured 
> about every 75 feet, I think the top and bottom of the tower is close 
> enough.  It's also where the pig tails tie into the coax runs at the 
> top, and into the SOR2 switching at the bottom so the bulk head 
> connectors should be as effective as the ones shown.
> >       I posted some time back in 2001 about applying 
> homemade ground clamps
> > to my runs of RG-213 at the top and bottom of my tower:
> > 
> http://lists.contesting.com/archives//html/Towertalk/2002-07/m
sg00698.html
> .  You can see photos of how Joe KC2TN followed my suggestions here:
> http://lists.contesting.com/archives//html/Towertalk/2007-10/msg00356.html
> .  The trick to getting a proper seal is to use Scotch 2200 Mastic Pads to
> cover the clamp and to bridge the cut in the coax shield.
I use a Scotch mastic tape, but don't have the number handy. I also use 
flooded heat shrink which I prefer with the bulkhead connectors as it 
seals the threads and prevents moisture getting to the connectors.  
Mastic tape would need to cover the entire connector to keep water away 
from the threads.  Also the heat shrink is just a whole lot easier.

The connectors shown in the Times Wire tutorial, or instructions are 
quite easy to make, once you figure out now much sheet metal to use. A 
half inch ground rod, piece of tubing, or dowel makes a good mandrel on 
which to form the clamp. Lay the mandrel in the center of the sheet 
metal, bend it around and form it with the "duck bill" vise grips that 
are about 3 or 4" wide. Use a punch to make the holes for the bolts.  
For aluminum a gasket punch will work nicely.

I believe getting the weatherproofing done properly would be the most 
difficult for most hams.

73

Roger (K8RI)

<snip>

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