[TowerTalk] Balun for Force 12 6 Element 20 Meter

[Jim Thomson]

Date: Tue, 21 Jul 2020 09:10:30 +0200
From: <dj7ww at t-online.de>
To: 'M?ximo EA1DDO_HK1H' <ea1ddo at hotmail.com>,
<towertalk at 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