[TowerTalk] Dipole center insulator strain releif

[K8RI]

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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