Frank Gilliland wrote:
First, sink a ground rod at the point where the coax will enter the
house. If you have a basement next to the ground rod, sink a couple more
rods so they are separated by ten feet or more and in the path of the
coax. Some people like to prep the ground by soaking with sal****er, but
in my experience that makes the rod corrode before its time, then the
salt leeches away into the ground water, leaving a very poor ground in a
very short time. I use galvanized pipe as opposed to copper rods because
they have a larger diameter (more rod-to-ground contact = lower
resistance), and they last longer. You can also thread the pipe for a
super-neat installation of a waterproof box......

Next is the coax installation. Run the coax down the mast or side of the
house to the ground rod. Don't run the coax near any wiring inside the
house. You can detect house wiring with a cheap metal detector. Avoid
sharp turns as much as possible. At the ground rod it helps to have a
waterproof box because you need to cut the coax, ground the shield, and
shunt the center conductor to ground with a choke (as per the diagram I
made yesterday).

About the choke: This serves two purposes. First, it shunts static
electricity from the antenna to ground. Second, it provides a path for
lightning if it should strike. Since the lightning will arc across every
loop in the choke, the inductance value isn't critical just as long as it
is high enough to block your RF (about 1 mH or larger for HF and above),
and the wire size is large enough to handle some current (#14 or larger
should be fine). One of those heavy-duty hash chokes for ignition noise
is ok, or you can wind your own -- use a large iron bolt for a core and
wind about 50 turns of #10 or #12 house wire. If you aren't running much
power, you can slit the insulation along the length of the coil so it
will arc at a lower voltage.

Then run the coax up into the house along side the grounding strap. Tie
them together with cable-ties if you want. Again, it's important that you
run these so they don't come close to any house wiring, and they should
enter at a location that is clear of easily combustible stuff. Terminate
the ground strap with a really big alligator clip, jumper cable clamp, or
whatever you have that makes a really good connection and can be easily
disconnected. The ground clamp from an arc welder is almost ideal.

Above the point where the coax and grounding strap enter the house, make
a hook or post where you can hang both when not being used. Remember that
if lightning hits, it's very possible that these will jump straight out
from the wall and dance around like a water hose, so make sure they are
held securely in place.

Inside the house, make yourself a grounding bus bar of copper or
aluminum. Put this on the back of your bench and use it to ground all
your equipment. To this you clamp on your grounding strap. When not using
your bench, unhook the grounding strap along with the coax and stow it
away. Also, to protect the coax, use an appropriate socket and short it
out before you stow it.

When should you unhook your antenna? There is a thing called the 30-30
rule: If you hear thunder less than 30 seconds after you see the
lightning, unplug. Don't plug in again until 30 minutes after the last
thunder. That's pretty safe. You can even improve on that by building a
lightning detector, many of which will indicate lightning even before you
can hear the thunder.

How's that?

Oh, I almost forgot..... coax length!!!!! The low impedance of the ground
will be reflected at the radio when the length of the coax & ground
strap, from the ground rod to the radio, are 1/2 wavelength. This means
1/2 wavelength -without- consideration of velocity factor because we want
a low impedance -ground-. And this means -- you guessed it -- 18 feet of
coax!

Very informative Frank, make sure we can reference that.

Dunno if average joe will completely comply, but he can't say you
didn't worn him! We pushed poles in the ground with the bobcat and
post hole digger, mostly for lightning. Out here where I live, by
the time the fire dept gets here with the tanker (no hydrants)you're
toast.

Ground is good. (like you said)

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