On 7/6/2019 9:37 PM, Hans Hammarquist via TowerTalk wrote:
The aluminum plate is connected to the tower with a 6-inch wide aluminum
strip. The tower, very close to the shack, is grounded with 9 grounding rods
I hope that combination of grounds is also bonded to all other grounds
in your home -- power, CATV, Telco -- and to your operating desk.
-----Original Message-----
From: Rich Assarabowski <konecc@snet.net>
To: towertalk <towertalk@contesting.com>
Sent: Fri, Jun 28, 2019 9:13 pm
Subject: [TowerTalk] Coax entry panel -- inside or outside?
This is an age-old topic but maybe someone can offer some advice. I'm
starting to redo my basement which will also have the new shack. In my
previous station, I had replaced one of the basement single-pane glass
windows with a piece of aluminum and had a bunch of feedthroughs for the
coax. It was grounded to the outside ground system by a short piece of
heavy copper cable. I never liked that solution as the connectors outside
were exposed to the weather and there was no provision for any Polyphasers.
I'm looking at the KF7P entrance panel boxes (see
http://www.kf7p.com/KF7P/EntrancePanels.html) which are an elegant way to
bring in coax. I've got a new spot identified where I could mount such a
box. It would be directly outside the shack on an outside wall, close to
ground level.
I did something quite similar that I built with the help of W6GJB's
workshop. It's mounted just as you suggest above. Photos and details
are at k9yc.com/CoaxEntryPanel.pdf I've abandoned Polyphasers in favor
the those sold by Array Solutions, both because I like the circuit
better and because the GDTs are field replaceable. With Polyphaser, you
get to buy (and install) a new unit.
However, there's another option which is more appealing to me. It would be
to mount a big aluminum plate (or copper-sheet clad plywood) in the same
location except it would be inside the house, rather than outside in an
enclosure. The coax would come into the house directly to the plate, with
Polyphasers and all the other antenna switching and filtering mounted on
that plate on the 2x4 wall, just above the foundation. That would
eliminate the need for the big outside steel box and would have everything
at the single-point grounding location. There would be a short ground
connection from the plate back outside to a ground rod, which is part of the
perimeter ground rod system and is also tied to the utility ground.
Any issues with doing it this way?
The only issue I see is the short length of the conductor bonding coax
shields inside the house.
73, Jim K9YC
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