Date: Tue, 21 Jul 2020 09:10:30 +0200
From: <dj7ww@t-online.de>
To: 'M?ximo EA1DDO_HK1H' <ea1ddo@hotmail.com>,
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Balun for Force 12 6 Element 20 Meter
<I don?t think so, he is not even using feed through insulators.
<73
<Peter
## speaking of feed through insulators, who makes em, that have a .25-20 or
.25-28 brass thread through the middle ?? Looked everywhere, and cant find
any.
Or is a feed through insulator even required on a nema plastic / fiberglass
box ?
A divider wall glued or rtved into place, midway between the 2 threaded
lugs should suffice to increase V breakdown from
water, rain, debris, gunk build up. I dont see any feed through insulators
used on steve, ve6wz, nema boxes, but the outputs
are well spaced apart.
## I have tried making hb feed through insulators using 1 inch solid
teflon rod, with a .25 hole down
the middle of each rod...done in drill press. This is on the outside of a
nema box. .25-20 brass threaded rod was then silver plated,
and inserted through each hb insulator, with a 1 inch diameter rubber gasket,
between nema box and bottom of teflon rod.
2 x more hb insulators, but a lot shorter, used on inside of box. I found 3
inch long, solid brass, .25-20 bolts locally, plus mating
brass nuts, washers etc.
## works, but nothing sticks to teflon for water proofing. I have not tried
white delrin rod, it might succumb to UV.
I was just trying to use what I had available around the shop.
Jim VE7RF
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