[TowerTalk] 2 questions

Dick Dievendorff dieven at comcast.net
Sat Jul 7 18:24:51 PDT 2012


1) Sounds like one or more of the relays in the box might be welded stuck,
perhaps it was hot switched? Can you open the relay box and take a look?
Pass a piece of paper between the contacts as a minimum while it's open if
it looks OK.

Several manufacturers offer antenna switches and controllers that follow
ICOM band lines and/or CI-V signals.  In alphabetic order, check Array
Solutions, Dx Engineering, Elecraft, Icom, KK1L, MFJ, microHAM, ON4AOI, and
Top Ten Devices (and there are surely others) for band decoders. Some of
these vendors also offer antenna relay boxes.  Being lazy here is good, you
end up with the right antennas at the right times. It's also a neat project
to home brew one of these.

2) I defer to experts on lightning. The advice I followed was to bond the
antenna shield to the tower at the top (I used a bulkhead UHF connector
clamped to the tower for the rotator loop to straight section junction) and
I grounded the switch box that the antennas connect to as well as grounding
the tower, and I have a bulkhead panel and lightning arrestors at the entry
to the house. There's a lot of info and varying opinions out there on best
practices for surviving lightning strikes.  I can't defend what I've done
other than to say it's what I was comfortable with for my installation, and
we don't get much lightning around here so I've probably overdone it.

73 de Dick, K6KR

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Gregg Seidl
Sent: Saturday, July 07, 2012 5:05 PM
To: TowerTalk at contesting.com
Subject: [TowerTalk] 2 questions

First question. I have an Ameritron RCS-10 that doesn't seem to work on all
positions. Mine only works on 1-4 with no connection on the other positions.
What would cause that? It almost seems like 2 and 6 are hooked together and
1 and 5 too! I also noticed it seems it has a lot of "bleed thru" for the
lack of a better term. I have thinking about getting a new switch but what
would I get that would be any better? Does someone make a switch that would
follow my Icom IC-7800 and PW-1 band wise? How do they plug-in? I know I'm
getting lazy but what is wrong with that,why not make it easier?

Second question is about the need/benefit of grounding coax cables at the
bottom of a tower. I am recabling my antennas after years of using the same
cables. I have read where you should ground the sheild toward the bottom of
the tower so I bought those grounding clamps from DX Engineering and they
same really nice but why do you need to do that? The tower in question is 85
feet tall Rohn 45 and has a 40 meter CC beam on it and also a CC WARC
rottable dipole  plus a 75 meter interted V on a metal sidearm. None of
those antennas are at ground potential. It seems to me that there is just
more connectors to go bad at some point. The tower is well grounded with 3
25 foot legs of number 0 copper wire with ground rods every 8 feet along the
25 feet of wire. It works too as the tower has been drilled by lightning at
least once with no damage, cables were disconnected from gear and tied to my
station ground. Just trying to understand and learn why some say to tie the
sheilds to ground at the
  tower base.

Thanks

Gregg K9KL
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