Topband: Grounding protection-Beverage?

[Brad Rehm]

"What are some options for lightning protection of a
Beverage...and...a remote preamp at the Beverage feedpoint?
How about an electric fence grounding apparatus? I have seen them in
the ranch stores.

"Mike Bragassa, K5UO"

Mike,

To take the topics in reverse order...The electric fence grounding
hardware I've seen here in Texas ranch country wouldn't be very
effective in protecting radio gear.  It's designed to keep a few miles
of fence from vaporizing.  They're not designed to protect a
transistor that could be ruined in a few microseconds.

My biggest concern has been with protecting the termination resistors
that get fried when they have to dissipate lightning-induced ground
currents.  (None of my Beverages has ever been "struck" by lightning.
All the damage has been caused by end-to-end differential earth
currents that were induced by lightining.)  You can put surge
protectors across them or you can use relays to open or short-circuit
the resistors.  But that's usually more trouble than it's worth.
Complexity is the enemy here.  I've just built the terminations so
that they're easy to replace every now & then.  Very simple.  Nothing
fancy.  (Hint: Look for bags of 2 Watt carbon resistors at hamfests.)

As for putting preamps at the beverage terminations: I think most of
us have chosen not to do this because we'd have to replace preamps
every now & then along with the terminations.  Resistors are cheap.
Preamps are not.

Coax loss is very low at 2 MHz, so unless you're planning to use a
mile of it, don't worry about it.  Think about adding some kind of
protection at the coax end of the Beverage, though--a spark gap, a gas
tube, a relay that shorts the ends of the line.  They should keep
lightning-induced voltages across the coax from exceeding its
breakdown voltage.  Bear in mind that when a lightning surge turns on
the gas tube or makes an arc at the spark gap, it will probably fry
the termination resistor at the other end.  Such is life.

73,
Brad, KV5V