> Wouldn't the cost of attempting to protect a relay be more
than the
> relay cost?
No. It would be very simple and inexpensive to protect an
open frame relay that size in a system where the voltage
across the relay in normal operation is so low.
I'd do it with wide half-hard thick brass strips bent around
the case to form a gap or some similar very close spaced
wide surface air-gaps between the element and boom. There
isn't any logical reason at all to insulate a large antenna
element for thousands of volts by omitting a cheap air gap
when that element might only have five hundred volts
(element to boom) in normal operation, nor is there any
reason to not put a bypass gap across relay contacts exposed
to lightning.
It might take two hours of total time and cost $20 in
materials to prevent all the work and expense of replacing
that relay.
My ~200 ft tower has spark gaps at the base and I haven't
ever lost a component related to feeding that tower despite
the fact the gaps show evidence of dozens of hard arcs from
lightning.
73 Tom
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