Jack Painter wrote:
"Taken as a whole, though, it must be effective, because the strikes do
no apparent damage, and they obviously get to ground somehow."

True. I`m skeptical of claims of lightning avoidance by discharging the
earth beneath the thunder cloud. I think the protection is from
substituting a more attractive target to the lightning than the one you
want to protect.

I`ve worked with too many radio towers. Many had inverted Copperweld
ground rods bolted to the tower tops with the pointed end aimed up.
Function of the rods was protection of beacons and other appurtenances
atop the tower.

The towers still get lightning strikes but the beacons don`t get damaged
from the tower hits when there`s a Copperweld lightning rod up there.
I`ve seen broken and burnt beacons from towers that didn`t have the
rods.

A radio tower with a sharp-pointed lightning rod is very salient and
should discharge the earth under and around the tower, if this is a
prctical course. From what I`ve seen these lightning rods do not prevent
lightning strikes but they do prevent some of the damage that lightning
causes.

Best regards, Richard Harrison, KB5WZI