After suffering seven lightning strikes in the last two years, I'm starting
to think the "ole ground rod per tower leg" just isn't cutting it anymore.
I remembered a QSO with an American Ham, stationed in Indonesia, about
lightning strikes. He told me that Indonesia had the highest incident of
strikes of any country in the world. For that reason, he said they had to
come up with some way to protect their installations. He told me a large
percentage of the YB guys use mast's that are made up of solid stock milled
down on the top end to a needle sharp point. The mast has an attatched
heavy solid copper wire which is dropped down the tower, and connected to
the ground screen. The theory is to bleed down the charge before it can
build to a lethal value. Apparently this workes well for them.
I've been following the Tower Talk discussion about lightning protection
with great interest. Some of the things I plan to do at my station is:
attatch a milled needle point 3/4" brass or bronze rod to my mast. The
sharp point will be the highest metalic object for miles on both towers. I
know they are going to take hits, but the tower's take hits anyway. I'm
going to get a grounding company to install a ground ring around my towers
and house. The rings will have a diameter of about 1/3 the tower height,
and will be cad welded to 8' ground rods driven each 16' and tied back to
each tower with 2/0 copper. They will have several 50' long radials in a
spoke pattern with an 8' rod cad welded each 16'. I'm also going to use
several porpuine spikes at various heights on each tower.
The feed lines and control cables are all grounded to the same heavy plate,
and connected to the ground screen. There are no physical connection's to
the rigs during down time. I physically open each cable and reconnect it to
the ground plate 5' away. The AC power is physically opened to my shack by
a breaker box. Also I physically unplug each AC cord.
I'm going to put a porpuine discharge spike on top of my 10' TV satellite
dish, and each clothes line pole. Also I'm driving an 8' ground rod near my
propane tank, and placing a needle sharp lightning rod 10' above it.
Of course I'm protecting my TV installation in much the same way.
With all this wild "el nino" weather one has to use the "here I am, come
and hit me" approach. It's gonna hit anyway, might as well give it an easy
path..
Did I miss anything?
73, Mick W4YV
ps/ As reported on WDBJ ch 7 TV in Roanoke, VA. ;A water tower in Lee
County, VA had a direct lightning strike last Friday night. The Tank
exploded and dumped 400,000 gallons of water on houses below, then
collapsed in a twisted pile of metal. Lightning is serious stuff! Don't
take it lightly!
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