Interesting, You made me look. (made me Look up coherer, that is).
An invention of Sir Oliver Lodge for detecting rf.
Your idea of using it as a lightning protection device seems to be a
misapplication.
But like I said, until now, I never heard of it.

"John Smith" wrote in message
...
For a receiving antenna, a coherer provides excellent lightning
protection.

Unfortuantly, on a transmitting antenna, the rf would immediately make
the coherer conductive and a direct short to ground (perhaps very low
QRP power could be used?)

One can easily be construted with a bottle filled with metal filings,
two bare wires are inserted into the filings (not touching and
seperated by a substantial amount of the filings), one wire goes to a
good earth ground, the other to the antenna.

If the coherer shorts to ground it only needs to be shaken to reset (I
would suspect in a real lightning strike the metal would be fused,
quite possibly even vaporized.)

John

"Jerseyj" wrote in message
...
Hi all,
For years I lived in an apartment and just had antenna's in the
attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of
serious
thunderstorms, and the accompanying lightning, I'm a bit concerned
about
properly grouding the antenna so that I don't fry the house *smile*.
I
know about some articles on the ARRL site, but was wondering if
anyone
else had some ideas or pointers on how to practically do this ?

Jerry