Doug,
I agree that you have a potential (ouch!) nightmare installation.
However, I can offer some suggestions.
First of all, it would be prudent to install an isolation transformer to
power your Quantar. Not a UPS, but a heavy-duty 1:1 transformer that
has a Faraday shield between the windings. C&H sales has some of these
for about $50. If the lighting circuit is 240 VAC or 480 VAC, that's
even better, because transformers are readily available to transform
either voltage down to 120 VAC. The key here is that you want to avoid
an unbalanced power feed, one that includes a neutral conductor, for
directly powering your equipment. The 120 VAC secondary of this
transformer should have a neutral conductor that is grounded right at
the transformer and nowhere else. The Faraday shield is also grounded
here. This ground terminal should connect to any building structural
steel at that level. Install utility-grade TVSS (transient voltage
surge suppressor) devices, suitably rated, on both the primary and the
secondary.
If the antenna is within six feet of a lightning down conductor, it
should be bonded to it. Likewise, if the repeater equipment rack is
within six feet of a lightning down conductor, it should be bonded to
it. Heliax or similar solid copper jacketed feedline is necessary.
I have a UHF repeater on a hilltop, and its DB420 antenna has been
struck by lightning several times over the last four years. Because it
was installed with positive grounding techniques, the repeater did not
go off the air. The secret is to ensure that all metal conductors at
each level are bonded together, so that the extreme voltages produced by
lightning stroke currents appear vertically and not horizontally.
That's a simplistic explanation for a complex issue, but it works. NFPA
780, the Lightning Protection Code, is a must read.
The R56 manual is an excellent guide- it's now in a single volume, by
the way- but when its guidance conflicts with either NFPA 780 or NFPA
70, the National Electrical Code, the latter codes must prevail.
73, Eric Lemmon WB6FLY
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