Before you run away:
When I built m freestanding shack I decided to screen it in by wrapping
(literately) with AL foil, kept in place with #18 brass wire (that I have
plenty of). I did this more as a mean to protect the inside from lightning
strikes. The shield is connected to the tower, next to the shack, with a 12"
wide AL strip. The tower is grounded with 9 grounding rods.
My idea is that, in the event of a strike in the tower, the shack will stay
electrically on the same potential as the tower, thereby minimize the damages
inside. All entries of electric wires, power, telephone, CAT5, coax, etc are
coming through in one location and are grounded (not the center conductor of
the coax not the hot wires of cause) at this location.
One big difference I noticed was a noticeable reduction of noise in the
receivers. This can maybe be because the closeness to the tower and the
antennas.
Good luck with your new shack and 73 de,
Hans - N2JFS
-----Ursprüngliche Mitteilung-----
Von: Chris Hoelzle <choelzle@cox.net>
An: 'GARY HUBER' <GLHuber@msn.com>; 'jimlux' <jimlux@earthlink.net>; 'TT
TowerTalk' <TowerTalk@contesting.com>
Verschickt: Mo, 5 Dez 2016 3:12 pm
Betreff: Re: [TowerTalk] Screened walls and floors
Thanks everybody for your thoughts
I think I will put my dollars elsewhere
NN6CH
Chris Hoelzle
choelzle@cox.net
Laguna Niguel, CA
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of GARY
HUBER
Sent: Monday, December 05, 2016 10:54 AM
To: jimlux; TT TowerTalk
Subject: Re: [TowerTalk] Screened walls and floors
It may be worth noting that some sheet rock (plaster board), ceiling panels,
and insulation (foam board) have metallic backing which increase the
difficulty of electromagnetic ingress or egress. Screen room? no,
attenuation of signals or interference ? to some degree, yes, maybe, based
on twenty years working in RF communications in large commercial buildings
with these materials and metallic oxide glass and metal floor pans for
concrete.
73 ES DX,
Gary - AB9M
On 12/5/2016 12:19 PM, jimlux wrote:
> On 12/5/16 8:55 AM, Grant Saviers wrote:
>> We built a Faraday cage big enough for an engineer and equipment and
>> learned that a special screen material is needed. Regular copper
>> screening has lots of crossovers that aren't really connected or
>> worse are oxidized contacts and can make the noise worse. A tech was
>> assigned to solder the wires in strips every 4 inches x,y,z, which
>> took a couple of days and made for a very unhappy tech. The results
>> were ugly but RF ok.
>
> You want "welded screen" as opposed to "woven screen" - standard steel
> hardware cloth would probably work.
>
> "real" screen rooms are made with aluminum or galvanized steel sheet
> (which is probably cheaper than screen, and a whole lot easier to make
> sure it connects to everything).
>
>
>
>
>
>>
>> I don't see a benefit for a station. IMO, it's a better use of time
>> to concentrate on a good building perimeter ground, the entry plate,
>> good chokes, and insuring no RFI sources from equipment inside the
building.
>
>
> Indeed...
>
> And you will find it very inconvenient that cellphones and VHF/UHF HTs
> don't work (or work poorly) in your shack, too. The old shack at JPL
> was a building with metal lined walls, and if the door closed, you
> can't raise the JPL repeater with a HT.
>
>
> _______________________________________________
>
>
>
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