Topband: Lightning

[Roger Parsons]

Many thanks to all for the replies I received on this
subject. Nearly everybody suggested that I talk to
Polyphaser and I have just finished a long
conversation with their technical support. They are
very helpful and very knowledgable.

I hope I have properly understood their main
suggestions/comments which were:

1. It is possible to protect the equipment in the
shack by having an excellent ground system and
appropriate suppression devices with single point
grounding, as has been well described in a number of
places.

2. Grounding with relays will have a similar effect to
grounding with MOVs, provided that the relays are of a
reasonable size. The protection comes from forcing two
points to be at the same potential - an open relay
contact will be jumped.

3. Because the coax run to my beverages runs across
poor conductivity soil (mostly rock), and because it
is so long, it will be impossible to avoid multiple
ground situations. Even a wide copper strap would have
so much inductance that it would not help - apart from
costing tens of thousands of dollars! If I could bury
the coax it would help, but that would also cost a
small fortune. 

4. As I cannot get a good ground at the remote switch
boxes, and as even if I do I cannot keep that at the
same potential as the station ground, it is better to
have no physical ground at the remote points.

To summarise, I can protect my main station equipment
by following well known protective procedures. I
should probably consider the remote switch boxes to be
sacrificial!

73 Roger
VE3ZI


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