"Richard Harrison" wrote in message
...
Dave wrote:
"and a corrolary of this (----in the event of a lightning strike,
nothing is at earth potential):
there is no such thing as an "rf ground"."

I`ve worked at a number of broadcast stations, none of which suffered an
iota of lightning damage, though often removed from the air
automatically for an instant by a lightning instigated overload. I`m
convinced the (120) radials around each tower in their antenna arrays
diverted lightning strikes to earth and the strike energy never entered
the transmitter building.

Brown, Lewis, and Epstein showed that earth radials can lower the
resistance of the RF ground connection to the vanishing point (lower
than the earth`s resistance in many cases, think parallel paths).
Resistance is low for lower frequencies and DC too. Skin effect goes
down with frequency and resonance in radials is eliminated by ground
loss.

Best regards, Richard Harrison, KB5WZI

when everything is properly bonded together the voltage of all the pieces
stays the same... everything may be 10's or 100's of kv above the infinitely
distant ground, but if they are all within a few volts of each other then
you'll never know it. where people get into trouble is they don't provide
for equalizing the local 'ground' voltage with the connections to the
outside world... i.e. you have to have a method to equalize those 10's of
kv's between ground and the power and phone lines coming into your house.
if you don't provide a low impedance path then your equipment will make one
for you, usually by releasing the blue smoke.