Working as a broadcast engineer at a MW (1390 kHz) station quite a few
decades ago, I have placed myself in the transmitter room so as to be
able to look at the towers as a Summer storm passed. That transmitter
did not have an automatic restore circuit. Well, I served as same.
When I saw the lighting strike the towers, I would reset the breaker.
The tubes (813s as I remember) would take that kind of abuse. My
reflexes were good enough in those days that the listeners hardly knew
anything happened.
That is another trade that has disappeared.
Richard knows! Have him tell about the cooked beasties across the
current shunts.
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA

"Richard Harrison" wrote in message
news:25140-40159FDA-

snip

I seem to be very lucky to never have damage with so many
opportunities
for damage. We never lost a transistor radio front end with countless
strikes as evidenced by the pitted antennas. We know the coax arcs in
broadcast stations. Most stations have automatic circuits to kill the
transmitter when the coax arcs.


In medium wave broadcast stations there is almost always a Faraday
screen to keep down the harmonic radiation. It gets countless zaps as
evidenced by pock marks and metal splattered about its shield box.Even
so, the coax gets arcs. When you are on the air, transmitter energy
keeps the arc alive once a transient has struck the arc. Most
transmitters are equipped with a momentary kill relay whose d-c coil
circuit is completed by the coax arc. As soon as the transmitter is
killed, the relay is de-energized and the transmitter returns to the
air.

In the 2-way radio world, the transmitter is going to drop out in a
moment when the mike button is released, or the station was in the
receive mode when the lightning hit and there is no energy to sustain
the arc.

The arc prevents conveyance of the energy to the radio. I never saw a
broadcast transmitter with evidence of lightning inside the
transmitter
and we have a good ides that these stations get struck almost every
time
a dark cloud passes by.

Best regards, Richard Harrison, KB5WZI