Edward Feustel wrote:
"Rob Roschewsk" wrote in message
. ..

I intend to build a "spark plug" type lighting arrestor.


These are available commercially. I have one but have not installed it.
Part of the difficulty is the voltage at which they fire! Imagine what
it could do to tuner and possibly transceiver. Best to ground the
antenna directly outside the shack when it is not in use and hope!

The idea behind this sort of device isn't necessarily to protect the
equipment, but is to provide a high current path for a direct hit, so
that the house doesn't burn down.

With coax, the shield is theoretically connected to a safety ground
outside the house, so that's the path.

With a balanced line, not connected to ground anywhere, there's no path
for the lightning impulse to take, except through the gear inside. Put a
0.05 inch gap to ground and it will easily conduct the several tens of
kA, with not a huge voltage (once the arc is struck, the voltage will be
down in the tens of volts range, and you could set the gap to whatever
works (say, around 500V).