On Fri, 12 Aug 2011 02:23:13 -0700 (PDT), DrYattz
wrote:

Having but recently returned to the world of shortwave radio, I'm
trying to be better informed about technical and safety issues than I
was as a kid. Now a homeowner with a mortgage and a homeowner's
insurance policy, I'm worried about lightning protection. I'm
receiving only, not transmitting. I have a ground rod just outside the
window where the antenna wire enters, and I intend to disconnect the
antenna outside the house when I'm not using the shortwave. But I
want to be extra careful!

So I'm considering some options. Which make sense to you seasoned
hams? Do any of these leave me open to my homeowner's insurance being
voided if I get a direct hit by lightning?

Hi Rees,

For the Home:

If you implement an intention to control lightning hazard, I would
suspect a jury would see it your way if you sued the insurance company
for failing to uphold their policy with you. However, they might
grieve at yielding to the insurance's arguments against you.

It wouldn't get to trial if you could demonstrate that you met the
electrical code.

The elephant in the room is: have you properly installed that ground
rod? Driving a long one deep into the ground does not qualify for a
"yes" to that question.

Ground is a very complex and mysterious thing for many, many people.
The electrical code doesn't go any great distance to inform you of its
mysteries, but it does give you solutions that work.

For the Receiver:

As for protecting your receiver from the lightning risk presented by
putting wire up into the air. All of the lighting protectors you have
links to guarantee you will see a couple of hundred volts across the
terminals. The receiver is not going to survive. The distinction
between near strike and direct strike are not really material to the
problem of frying the receiver. The difference is merely one of
personal drama.

You may encounter this potential even on a seemingly cloudless day.

Receiver solutions:

Short the potential. This may be accomplish by using the "Folded
Dipole" design of horizontal antenna. A "Folded Monopole" design for
a vertical antenna. Other designs that employ loop coupling would
also reduce the risk. All such options offer a DC short, but with an
RF impedance. This insures static electricity drain, but allows an RF
voltage (the short wave signal) to develop. A large inductor across
the feedline or conventional dipole feed point provides the same
protection. The coil acts as a DC short, but as an RF open.

Some SWL lightning protectors employ paired diodes to reduce the
voltage risk to less than 10V - trivial indeed. Unfortunately, these
same diodes will conduct in the presence of large RF fields (recall my
discussion about nearby AM transmitters, and "nearby" is relatively
near for RF but seemingly distant if you had to walk or even drive to
it). This conduction will ruin listening opportunities with a jungle
of mysterious signals "that shouldn't be there." Example, hearing an
FM rock station feed on the 60M band.

Having a Tuner between your radio and antenna shifts the dynamics such
that the gap arrestors are useful - until you throw the bypass switch.

73's
Richard Clark, KB7QHC