[Lowfer] That 8KC 'Phantom Loop' Antenna.

[JD]

> We get storms here in NE Texas with nasty lightening.  Any strike even
> remotely close to this cable is going to set-up some hefty surge currents
> in it.  Any recommendations of how best to protect the amp from these?

The only completely reliable way, particularly with a solid-state amp, is
going to be to disconnect the cable entirely every single time a
convective cell moves in or begins to form within 20 miles of you.

Having done similar experiments 35 or so years ago with a significantly
shorter cable run, I predict you'll find your setup to exhibit between
several tens of ohms to a few hundred ohms resistance (maybe more,
depending on the cable and ground systems) in series with a more inductive
reactance than you'd suspect.  You'll probably use transformer matching
for the resistance, in series with a bank of capacitors to resonate the
system, and those reactances will further compound the difficulty of
finding lightning protection components capable of adequate protection.

In my setup with a tube type amplifier running under 100 watts, I was
seemingly able to avoid damage with a few heavy duty industrial MOVs.
(That was for backup more than primary protection, though. I still
disconnected when I knew a storm was approaching, because I once had the
experience of vaporizing a fuse rated for 100,000 A interrupt that I'd
left connected between two similar grounds during a lightning storm.)  A
solid state amplifier is going to be far less tolerant of transients, and
the more power you run, the harder it'll be to find a suitable protector
that can guarantee removing those transients while not clipping your audio
RF.

John