Before WX0B switched to use feed through insulators I replaced two of his
baluns on Optibeams at a friend.
Baluns were made from RG393 wound through ferrite toroids.
Around the stainless steel screws the boxes were burnt out, I guess that was
caused by current, not by voltage and went into a loose connection and
thermal runaway.
I also use feed through insulators, either ceramic from my junkbox or home
brew teflon.
New insulators can be found here:
https://www.daburn.com/10-58ceramicfeed-thruinsulators.aspx
73
Peter
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
<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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