"Spike" wrote

Here in the UK I'll think you'll find the lightning conductors have
greased joints.

I always thought it was the origin of the term 'greased lightning'....

(only joking)

--
from
Aero Spike

That is funny. But since this has now become rec.batteries.car (just
kidding):

The reaction from battery acids, air and dirt are minimized with grease. But
mechanics who grease the inside of the cable-clamp and outside of the
battery post *before the connection is made* are not helping the electrical
connection - they're applying preventative maintenance for idiots - who
never clean their battery posts. Conductive paste is much more expensive
than grease. Those who know what they are doing use the former. Conductive
paste is specified in US Lightning protection (NEC-70/NFPA-780), and grease
is not allowed to be used in any mechanical connection there. Back to
antennas for a moment, we all know that grease (or conductive pate) does not
provide waterproofing of any kind. And most of you will accept that grease
is a dialectric, not a conductor. But after making a mechanical joint with
conductive paste (ensuring no air enters the joint, and conductivity remains
per the connected materials), and proper waterproofing is applied, you have
a safe and maintenance-free joint that will last for years. Or it would
anyway, if the same codes didn't require you to expose and mechanically
tighten every such joint once a year. That's why the expensive exothermic
(welding) of all grounding electrode conductor joints becomes a savings in
the long run. Unfortunately that is never practical along rooflines up on
masts and towers. So those mechanical joints must provide as little
impedance as possible, and survival of the equipment depends on this.

Because all transmitter antenna radials automatically become a part of the
lightning protection system, the materials used should be the best you could
afford, not the cheapest you can find. And the connections should likewise
be the best possible. The transmission system will be more efficient, and
safer.

Jack Painter
Virginia Beach, Virginia