[PVRCNC] Re: [PVRC] Lightning protection

[Jim K4QPL]

I agree with Guy. We can do all the logical things, but whether we get 
burned or dodge a bullet seems somewhat random. We had one heck of a storm 
here last night with strikes every 4 or 5 seconds. I had left all the 
antenna coax feedlines plugged into a grounding strip at the tower but 
nothing disconnected inside. One strike was an incredibly bright and loud 
snap right outside the house with ZERO time delay. As there was no power 
line, phone or TV cable blink so I assumed my tower got it. Was almost 
afraid to go out to the shack which is in a detached garage after the storm 
passed. But either it missed or the grounding systems did what they're 
supposed to. No apparent damage and the rotor turns. Guess it just wasn't my 
time!  A couple years ago my W1GEE interfaces and the Kenwood interface 
board got fried in a winter storm that wasn't much of anything. Go figure!

73,

Jim, K4QPL
----- Original Message ----- 
From: "Bill Tippett" <btippett at alum.mit.edu>
To: "Jack Colson" <jackcolson at netsignia.net>; <pvrcnc at mailman.qth.net>
Sent: Friday, July 29, 2005 11:17 AM
Subject: [PVRCNC] Re: [PVRC] Lightning protection


> At 10:30 AM 7/29/05, you wrote:
>
>>Hi Bill,
>>The equipment was not connected to the AC line, antennas or telephone 
>>lines.  The 110VAC to the input to Isobars was removed from the wall 
>>outlet.  The output coax from the Ten-Tec amp was just laying on the 
>>floor, about a 6' RG-8 cable.  I left all of the intra  cabling between 
>>the equipment connected.
>>
>>We had a discussion in the FL area concerning huge surge currents coming 
>>in via ground connections thus I had removed all equipment connections to 
>>my local 10' copper ground rod.
>>
>>The Ten-Tec 425 amp input PC board had a big burn mark on the PC board. 
>>This input was connected to the FT-990 output via a 4' lenght of RG-58. 
>>The FT-990 seems to be OK.
>>
>>Now in all of this equipment which was just sitting on the desk together 
>>the following was damaged.  The W1GEE serial I/F between the radio PC and 
>>FT-990, the Astron 35 amp power supply appears to have had a small 
>>regulator IC blown, in my HB Idiom press keyer, a 78L05 regulator was 
>>blown.  Moreover, all memories in the FT-990 were at their default state.
>>
>>On the other side of the room my Dell PC was totally disconnected and the 
>>modem was blown.  Interesting enough, I had left a telephone and answering 
>>machinc connected to the tel. line and they were blown.  I forgot to 
>>removed my xyl's PC connection to the tel. line and that modem survived. 
>>The PC was not connected to the AC line.
>>
>>I am glad that you have been so fortunate !!!!!  This is the second time 
>>for this to have happened in a five year period.
>>
>>My question is now would I really be better off keeping the ground wires 
>>on the gear?  All coax cables shields entering the shack are grounded at 
>>the point of entry.
>>
>>Any suggestions or comments are welcome.
>>
>>73
>>Jack, W3TMZ/4 near the Gulf in Central FL.
>
>
> Hi Jack,
>
>         Wow!...but a couple more questions:
>
> 1.  I assume the phone line was not connected to
> your radio equipment in any way.  I think that's
> correct but just wanted to confirm.
>
> 2.  How far away is your tower from your shack?
>
>         If the problem was induction from a
> very close strike, the prudent thing would be
> to disconnect all potential "antennas" that could
> pick up any induction.  I would also disconnect
> the equipment from any ground...i.e. no connections
> AT ALL.  Apparently even your 6' of RG-8 was enough
> of an antenna to pick up what apparently was an
> extremely close strike.  I may not be having problems
> because my most likely tower to be hit (180' with
> nothing on top) is about 300' away.  I have another
> ~100' high about 150' away but the Yagi's on it
> seem to dissipate charge build-up (although
> it has been hit at least once to my knowledge).
>
>         If, as I am assuming, your tower is quite
> close to your shack, the only solution may be
> to completely disconnect all interconnections
> that can serve as pickup antennas.  I have often
> heard our house wiring "click" with nearby strikes
> which I assumed was internal house wiring induction
> (since the service entrance has a surge suppressor
> at the meter).  We have never had any damage
> other than losing an unprotected DirecTV phone
> modem (I forgot about that one when installing phone
> line surge suppressors!)
>
>         I thought I was being very prudent, but
> now you make me wonder about even removing
> interconnections!
>
>                         73,  Bill  W4ZV
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