On Sunday, March 8, 2015 at 8:22:14 AM UTC-4, Leon Fisk wrote in rec.crafts.metalworking:
>
> > I bought a single-pole relay rated for "only" 75KV once. It was the
> > size of a desk lamp and opened the contacts several inches.
> >
> > Ouch!
> >
> > The way I remember it the product used standard relays. The key
> > was that in the off/relaxed position everything was shunted
> > together to common ground point. Lightning could still jump
> > the relay but it would be greatly reduced with everything
> > shunted/grounded together. It was a pretty ambitious scheme if
> > I remember correctly. The antenna lines were all disconnected,
> > shunted too. Depending on the frequency, antenna switches can be
> > pretty expensive too...
> >
> > One of the radios I used to work on was the Motorola Micor series.
> > They
> > had an interesting antenna relay in them. They used two magnetic
> > reed-switches encased in an aluminum (I think it was
> > aluminum) housing.
> > One switch had a magnet shrink wrapped to it keeping it in
> > the closed position (receive side). A small coil (12vdc) went
> > around the metal
> > case. To transmit they applied 12vdc to the coil which in
> > turn closed
> > the open reed and opened the one with the magnet affixed...
> > For an overall image:
> >
> >
formatting link
$_1.JPG
> >
> > They made a great lightning arrester. Many, many times that is
> > the only part I would have to replace after a tower lightning
> > strike. If you
> > took one apart, quite often the two reed-switches would
> > be completely obliterated, just blown to bits... Motorola had
> > a lifetime guarantee on those relays. Sent many of them back in
> > for warranty replacement. You
> > couldn't tell what happened to them without taking them apart :)
>
> Psst... John, wake up, you're dreaming...
>
> I worked in two-way radio communication most of my career. Several of
> the towers I serviced equipment at were grounded to R56 spec, which was
> very ambitious and the best at the time. The equipment still took hits
> that caused considerable damage...
>
> And other towers that had little to no grounding and got hit regularly,
> had very little equipment damage. Go figure...
>
> Maybe our lightning had more oomph than your lightning ;-)
No. John is spot on. Leon, maybe its just that you haven't been through three or four years of electrician school.
Lightening or surge arresters have been in use for years (here in the 21 century). Why do you think aircraft hardly ever get electrical equipment damage, though they get struck more often than the ground experience you claim above?
Look up what an surge arrestor (or lightning arrestor) actually is:
formatting link