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.
> Dick NY1E
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