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Re: [TowerTalk] Dipole center insulator strain releif

To: K8RI <K8RI-on-TowerTalk@tm.net>
Subject: Re: [TowerTalk] Dipole center insulator strain releif
From: Bob K6UJ <k6uj@pacbell.net>
Date: Sat, 21 Apr 2012 20:03:37 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Roger,

I like your design,  I have made a similar arrangement, including the #31 cores 
but am not that satisfied with my 
scheme.  I let the RF choke hang below unsupported.  If you can do a picture 
that would be great.

Do you know what type of plastic the white cutting boards are ?   They sure 
look like teflon although I'm sure they are not, hihi.  
I am thinking of getting one and trying it for a dipole center support panel 
like we are discussing.  I guess the first thing to do is to see if they
are immune to RF.  Putting one in the microwave for a little bit to see it gets 
warm might be a good test.  The ones I have seen are about 1/2" thick,
and they sure look like they are begging to be used on antennas, hihi

Bob
K6UJ





On Apr 21, 2012, at 5:18 PM, K8RI wrote:

> On 4/21/2012 6:17 PM, Dick wrote:
>> I just got a rope over a tree after 4 years of trying. I need a dipole 
>> center insulator that has strain relief for the coax. To clear the branches, 
>> the coax will be pulling against the center support rope. All the center 
>> insulators I've seen have an SO-239, it doesn't seem like putting that 
>> strain on a PL-259 is a good idea... Do any have a strain relief??
> 
> I make my own out of 1/2" Plexiglass, or two 1/4" sheets laminated 
> together with epoxy.  I drill a hole in the center slightly larger than 
> the coax and round the edges. Typically I make a RF Choke of 5 or 6 2.4" 
> # 31 cores with 5 or 6 turns of BuryFlex(TM) coax. I typically make the 
> choke part of the feed line so no PL-259s are under tension.  It takes 
> very little (relatively speaking) to pull the coax out of one even if 
> it's thoroughly soldered. I will often put a connector on the antenna 
> side of the choke and run a coax pigtail from it to aid in water 
> proofing.  To take up the antenna strain I use a 4 or 6" ceramic 
> insulator  TieWraped to the Plexiglass. I drill holes just large enough 
> for the tiewraps.  Remember that nylon does not stand up well to UV or 
> out in the elements nor do cheap cable ties.
> 
> So I end up with the coax going through the Plexiglass, then the choke 
> on the other side and finally to the antenna ends at the ends of the 
> ceramic insulator.  In some cases I epoxy the coax in the hole through 
> the Plexiglass.  I have some of these supporting about a 100' of 
> BuryFlex(TM) back to the tower while the antenna may be under between 
> 100 and 200# of tension such as the 75 meter fan dipole.
> 
> I hope to have a photo up yet this evening.
> 
> 73
> 
> Roger (K8RI)
>> 
>> Thank, 
>> Dick NY1E
>> www.ny1e.com
>> _______________________________________________
>> 
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