[TowerTalk] Fwd: Station grounding in a steel enclosure?

[Hans Hammarquist]

 I have a similar situation with my shack. It has a continuous shield made of Al foil and Cu wire. This shield is connected to the tower with a (really) heavy Al strip (~ 12 inch wide). All wires from the tower follow this strip and enter through a steel panel. The panel is connected to the shack shield.

I don't think is matter if the shield is connected on the inside or the outside as long at it is very secured (electrically) to you steel enclosure (shield in my case.

How do you plan to operate your equipment. The space seems very limited to me.

Good luck and 73 de,

Hans - N2JFS

 

 

-----Original Message-----
From: trentkd5ia--- via TowerTalk <towertalk at contesting.com>
To: jim <jim at audiosystemsgroup.com>; towertalk <towertalk at contesting.com>
Sent: Sun, Aug 28, 2016 8:34 am
Subject: Re: [TowerTalk] Station grounding in a steel enclosure?



Jim,
 
Thank you for your comments.   The plan is to bond all shields and bypass all the conductors coming into the enclosure, but should they be bonded to the outside wall or can they be bonded to the inside wall?  The valve box is made of heavy corrugated steel, and it will be easier to have the connections inside the enclosure rather than outside, under the ground.  Or will it be sufficient to bond and bypass the coax and other cables at the tower base, twelve feet from the enclosure?
 
I didn't exactly plan to have a Faraday cage--this big valve box just seemed to be  the most convenient and inexpensive way to keep my equipment safe and secure out on the prairie.
 
73 de Trent   K5XM
 
 
 
-----Original Message-----
From: Jim Brown <jim at audiosystemsgroup.com>
To: towertalk <towertalk at contesting.com>
Sent: Sun, Aug 28, 2016 7:25 am
Subject: Re: [TowerTalk] Station grounding in a steel enclosure?

Trent,

Your first problem is that your box is NOT a shield if cables come 
through openings in the box without their shield being bonded to the box 
at the point where they enter. You must also bond or bypass (with 
feedthrough caps) all other leads coming into the enclosure, like power, 
control lines, audio lines, keying lines, etc. Any one of these lines 
that does not have its shield bonded to the enclosure or come through 
the enclosure via a feedthrough capacitor destroys the shielding.

As to where to put the Polyphasers -- I would use the "feed through" 
type and bond them to the enclosure.

The larger question is why you need a Faraday cage in the first place. 
Few stations do. What most stations need is proper BONDING, proper 
grounding, proper power, and proper interconnections between equipment. 
Study http://k9yc.com/GroundingAndAudio.pdf

73, Jim K9YC

For On Sat,8/27/2016 10:28 PM, trentkd5ia--- via TowerTalk wrote:
> My remote station is approaching completion.  A 70' tower, wireless internet, solar power and RemoteRig with a TS480 is all operational.  Still in progress are the antennas to be mounted, and lightning protection.  I have a question about grounding.  The electronics are housed in a valve box--a galvanized steel cylinder 5 feet in diameter and 4 feet tall, with 3 1/2 feet of that in the ground.  A removable steel lid covers it.  All cables are in PVC pipe and enter the housing under ground level, and the valve box is 12 feet from the base of the tower.
>
> The grounding system will consist of 9 ground rods, 3 connected to each leg of the tower and extending out from the tower.  The valve box will also be connected to the grounding system.  Polyphasers will protect against surges.
>
> My question is, can I install the surge protectors inside the steel housing, or should they be mounted outside the valve box?  I'm thinking that the steel cylinder possibly acts as a Faraday cage, and the grounding connection and surge protection should be attached on the outside wall of the housing.  Any comments or suggestions, please?
>
> Thanks!
>
> Trent K5XM   on the windy and lightning prone West Texas plains
>
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