Jim,
Thanks for the advice. Skin effect was what I wanted to hear about!
The valve box, or drum, isn't completely air tight. I have insulated the lid
and temperatures inside haven't been excessive. Being mostly underground
helps. And, I'm using a Morningstar charge controller. The system is 12 volt
so no need for MPPT.
Thanks again!
73 de Trent K5XM
-----Original Message-----
From: Jim Brown <jim@audiosystemsgroup.com>
To: towertalk reflector <towertalk@contesting.com>
Sent: Sun, Aug 28, 2016 6:16 pm
Subject: Re: [TowerTalk] Station grounding in a steel enclosure?
Trent,
It sounds like you have a good handle on things. Since your primary
concern is from external sources (lightning, noise) I would bond to the
outside of the enclosure, taking advantage of skin effect to keep those
external currents "outside the box."
There is, of course, the need for ventilation to allow heat dissipation,
with the conflicting concern for rain/snow/moisture intrusion. A tricky
design problem. :)
I'm guessing you'll be using solar power. This may seem
counterintuitive, but I would try to put all electronics for that system
inside the box, which shields it from antennas. And all power wiring
outside the box should be twisted pair, to minimize radiation of
switching transients produced by the charge regulator. Try to choose a
low noise charge regulator. Genasun makes a line of MPPT charge
regulators that is very quiet, but, so far, they only make them for
small systems. Their largest one is rated for 8A for batteries up to
48V. I'm using one rated for 10A to a 14V LiFePO4 battery.
73, Jim K9YC
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