In a message dated 97-04-10 15:21:42 EDT, you write:
> Every time there is a thunderstorm, why don't the commercial stations
> (radio and TV) shut down their xmtrs and unplug their coax?
>
> Do they do a grounding job so far above and beyond the Polyphaser
> standard (ground rods, bulkhead, surge suppressors, common point
> ground, etc.) that it's OK to stay connected? Or, do they just keep
> replacing equipment as it blows up?
>
> Bottom line, what does it take to stay connected? How about something
> like a Top Ten box that automatically switches all lines to ground
> when off the air?
There's no secret to building an effective ground system. It just
takes time and money. Hams, being a parsimonious bunch, are reluctant to
spend the money.
While whole books are written on the topic, here's my 2 cents worth. An
effective ground system consists of hardware that connects together all of
the things that may be a path for a lightning strike (towers, antennas,
cables, AC line, phone line, cable TV, etc.). The idea is that you want to
have everything at the same voltage potential so that they all rise and fall
at the same rate. When they do that, there's no arcing or unwanted
catastrophes.
The basic scenario is to install a Single Point Ground System that is
installed at the building entry. It shunts everything to ground before it
goes in the building. If you can keep it outside, then you don't really have
to do much inside. IMO disconnecting the cables is more psychological than
preventive.
For a more involved explanation, I have copies available of the
grounding chapter from my as yet unreleased book on tower construction for
hams. An SASE to TOWER TECH, Box 572, Woodinville, WA, 98072, will get you a
copy.
73, Steve K7LXC
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