[TowerTalk] LMR600 male DIN - baluns, coax and grounding immediately

[john at kk9a.com]

I run Heliax up the tower and use Andrew ground kits.  The kits are very
nice and including plenty of butyl rubber and tape for water proofing.

John KK9A


To:	<towertalk at contesting.com>
Subject:	[TowerTalk] LMR600 male DIN - baluns, coax and grounding immediately
From:	"StellarCAT" <rxdesign at ssvecnet.com>
Date:	Thu, 8 Sep 2016 10:51:11 -0400

and more than likely ANYTHING you had done to waterproof the connectors
including water proof connectors would have failed with a direct hit. Just
because a connector might be water proof doesn't make them a magic energy
sink capable of thousands of joules... Grounding the shell at the top and
bottom (and middle if over ~75') which is what I plan on doing is probably
the best thing - and I'm sure you had that as well.

Indeed therein lies a problem - how to do this AND seal it ... at the base
I'll have a box on the tower so that connection is inside (metal box with
a separate connection from the inside to the tower as well). All of the
antennas but one are hairpin matches so it will be DC grounded through
that at the antenna and the 2 switch boxes (stacking and then antenna
select) will accomplish two more grounding points ... the 4 element
Optibeam 40 will need a think through.... and the rotary 80/75 dipole at
the top - its hairpin is a coil and is not grounded ... hmmmm....

that brings up a question: Does having a balun at the antenna - assume a
good one - allow one to ground the shield of the coax to the tower
immediately ... i.e. say the DE is out 20' ... there is a balun there ...
can one have another connection at the tower and have that connection
shell grounded - does the balun make this possible? I believe I know the
answer (and I'm trying not to get in to the QUALITY and capability of the
balun) ... but would like to hear from the experts - K9YC?

Gary
K9RX