While researching and preparing for my insurance filing for my
lightning strike, I remembered that I had a good friend from the 60's
who used to be a local ham and he had worked for Ga Power...he ended
up being their lightning guru for 35 plus years...further research
with closed loops of of storm tracking radar narrowed the search for a
day and time of the event.
My friend then plugged into a national data base of lightning strikes
and determined the exact location (within 280 meters which is
exceptional accuracy) the intensity of the strike.
It ended up being three strikes in 37 milliseconds totalling 87,000
amperes...a really significant strike...it hit my 15m tower...that
tower is 155 ft tall and has a ground field of 15 ground rods
extending away in a field with one ground rod in the nearby lake...the
damage to the station would have probably been much worse had I not
had so many ground rods, they helped dissipate some of the strike. The
intensity of the strike induced huge voltages on my CAT5 cabling in
the shack that was used to network 19 computers in my multi-multi
station...each computer was attacked thru the USB devices and thru the
NIC inputs...radios were damaged even though they were disconnected
rom AC and antennas. A total of 7 MicroHam USB Microkeyers were
destroyed...2 radios were totally destroyed, Astron power supplies
were toasted...9 computers were destroyed...numerous rotor control
boxes and the list keeps going on and on...
Lessons learned:
1. you can't have too many ground rods
2. disconnecting AC power and antennas is great but not sufficient
3. CAT5 cabling needs to be protected or disconnected
4. A bulkhead metal grounded entry for ALL antennas, rotor control
lines, and switching must b implemented
5. Towers need to be grounded together and to the house grounding
system to be effective
6. and in the event of a "finger of God" strike be prepared for damage
no matter how prepared you think you might be.
73 de Rick NQ4I
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