From: "Jack Painter"
Organization: Cox Communications
Newsgroups: rec.radio.shortwave
Date: Sat, 23 Apr 2005 13:13:33 -0400
Subject: Antenna Suggestions and Lightning Protection


"Greg" wrote
Jack the Painter wrote:

Greg, before you entertain such suicidal thoughts again, please browse
my
website explanation of why your home's electrical wiring and ground
system
are not meant to handle lightning surges.

(Snip)

Well, by "entertaining such ...thoughts" I guess you are referring to my
questioning whether it was safe to ground the antenna to electrical ground
when not in use. As you, and RHF pointed out, it isn't.

Drilling the patio won't help, as I still would have to run the ground
wore
across the room. Drilling through the floor? Nope.

So here's the deal - I can put up the antenna, ground the coax (shield) &
"balun" at the far end, run the coax to the AC service ground (& ground
shield to it there), install lightning arrestor, then run the coax through
the attic, down the wall, and out to my NRD-525. so far, piece of cake.
Now, when when thunder storms come, I disconnect the coax from the xcvr
and
do what with it? Prob. just let it hang, since the coax pretty well
grounded already?

Thanks Jack, I will check your web site.

Greg
W. Central Fla.
Lightning Capital of the U.S.

Greg, you've got it. And yet you still have that dilemma that faces
thousands of hobbyists; what to do with that disconnected coax? Good news!
Since yours will now be shield grounded at the antenna base and the AC
service entrance ground rod, and a lightning arrestor providing center
conductor protection at the AC service ground rod, very little potential
exists at the end of that coax, and it should be left connected to your
radio at all times. Congratulations.

HOWEVER - you should disconnect the radio's AC power supply (from the back
of the radio) before a thunderstorm. This is because there is still a high
probability that damage from a nearby strike would be imposed on your
electrical system. Only installing fairly expensive AC surge protection
equipment can protect against this danger, and they are not available at
WalMart or Circuit City, etc. I'm not saying you can't use cheap
line-protector power strips to power your radios. But do not rely on them to
do anything except cause damage if your powerlines take a hit, or a strike
comes very close to your home, and imposes major energy on your house wiring
itself. My cost to protect from AC surge damage was over $2,000 in labor
and materials, and it cannot be done by the homeowner. So unplugging all AC
power to sensitive equipment remains an important part of lightning
protection, EVEN if you do the very sensible and safe things regarding
antenna grounding, shield grounding, lightning arrestors, etc. That part is
not very expensive at all, and provides a LOT better sleep when you don't
have worry about those feedlines entering your home.

About bonding. You are "bonded" to your home's AC power ground system when
your radio's three-prong power cord is connected. As long as your radios
have no other ground connection, that's fine. But when people bring coax
feedlines into their station, there exists the possibility that a nearby
strike (to a tree next door for instance) will cause massive ground
potential rise around your antenna and radio grounding systems. This can be
drawn up into your shack, and exit out the radios through the AC power line
(including it's third-prong ground connection). That is serious, and can be
avoided only by disconnecting the power cords before a storm. But it can
also be mitigated by running good bonding connectors from the OUTSIDE
shack-ground rod, around the house to the AC service entrance ground. Then,
ground potential rise from a nearby or direct strike will MOSTLY go the low
impedance path to your AC ground rod, and the system remains "balanced" with
no terrible potential existing between any two points. As long as there is
no exit path out the back of the radios (the AC power cord), and your coax
shield grounding is done, and arrestors guard the center-conductors of the
coax, you will be fine.

Best regards,

Jack Painter
Virginia Beach, Virginia

Okay, good information Jack. I do have surge protectors on all the
electronics, but I know that's not the best protection. Our electric
utility will install whole-house surge protection at a nominal charge per
month. I'd better get that done ASAP.

For now I'm using an active antenna in the attic. When I build one outside
I will follow your guidelines for sure.

Thanks,

Greg