>Lightening protection is pretty well standardized and there is plenty of
>information available. There is no 100% guaranteed, fail safe
>protection even for the 24 X 7 stations, but they are well protected
>from most strikes. It's just that there is no guaranteed protection
>from the so called, "super strikes" that can be many times more powerful
>than your run of the mill, every day strikes.
Roger,
I totally agree. All you can do with lightning is do your best to manage
it. Twenty some years ago, after just putting up the tower I took a strike
and toasted most everything in the shack as well as burning a hole in a
water pipe touching rebar in the slab. I read Polyphaser's ( Now
Transector) "Grounds" booklet and installed as good a ground system as I
could. I have a 120 ft Rohn 45 about 100 ft from the house with 27 stainless
steel ground rods under it. My entrance window (panel) has around 8 more
ground rods connected to it. I don't know how many strikes it has taken
since, but in one night, my neighbor saw the tower take two direct strikes.
I have a DX spotting cluster so I want to have it connected while I am not
here. I have never since disconnected anything - there is just too much to
manage without getting complacent. All the equipment is connected with 2"
copper ground straps connected to the entrance window. The complete shack is
powered through a Polyphaser AC line protector - also grounded to the
entrance window. The house entrance electrical box is a few feet from the
radio entrance window and is connected to the ground system. The HDR-300
rotor is at the 60 ft level and the control lines go through a box of MOV's
and is grounded at rotor level as well as at the ground window and
additional MOV's mounted inside the rotor control box. Believe me, you
don't want to buy repair parts for that controller - don't ask me how I know
that.
Since then, I have had damage only to the antennas. One of the loading
coils on the Cushcraft 40 was just missing after a strike
Through my occupation, I talk frequently to the Transector Rep. He tells
me that over time (< 5 years) MOV's lose their effectiveness. I've not
heard this before. If this is true, need to get on that.
Another note: KA9A, when he lived in town had his shack on the second floor
of his garage with the tower next to the garage. He took a strike on the
tower and everything was disconnected from the antennas and the AC power.
Yet almost everything was destroyed. I had loaned him a 24V power supply
which was sitting on the floor at least 2 ft from anything and nothing
connected to it. The fuses in the DC power line (again, not plugged into
anything) were blown and the supply trashed. I suspect that the EMF from
the proximity of the tower was the culprit as the strike found its path down
the tower to a single ground rod.
Jim, KR9U
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