One solution in the case of "induced currents" is to construct a Faraday
Cage around the shack. Now this isn't as difficult as one might imagine,
although my application isn't pretty and might not meet XYL approval.
I finally found a good use for some defective 1/2" Andrew hard-line. I
configured and installed a loop around the perimeter of the room at the
ceiling and again at the floor. Then I connected the 4 corners vertically
to the top and bottom loops. All connections were made with some copper
strap, a torch and solder along with a small hose clamp. A single ground
strap was then connected to the outside common ground point and it's done.
A nearby strike will induce lots of current into the combination of 6
electrical loops and not into the associated wiring of the station.
73
Bob, K4TAX
----- Original Message -----
From: "Duane A Calvin" <ac5aa@juno.com>
To: <tentec@contesting.com>
Sent: Sunday, November 20, 2005 11:17 PM
Subject: Re: [TenTec] Orion 2 lightning rule
> Along those same lines, a good friend here had his computer and Yaesu
> FT-1000MP connected together, but both were disconnected from both power
> and antennas. Still, a direct hit on his antennas absolutely fried the
> MP. Didn't bother the computer at all. He has Polyphaser incoming panel
> and antennas were disconnected there. Really weird. It's just
> impossible due to induced currents to know what is going to happen to
> gear!
>
> 73, Duane (and now he has an Orion II on order)
>
>
> On Sun, 20 Nov 2005 18:38:04 -0600 Robert & Linda McGraw K4TAX
> <RMcGraw@Blomand.Net> writes:
>> I think Steve's account of the lightning damage is clear, very
>> logical and
>> detailed. Case and point: disconnected antennas is not adequate.
>> One must
>> disconnect the ground and the AC line too. From his description it
>> reads as
>> though this was pretty much a direct strike. As I said before, to
>> handle
>> that much current it would take a conductor the size of a truck.
>>
>> In one project to which I was affiliated related to lightning damage
>>
>> control, we measured some 6000 volts between the bottom and top of a
>>
>> standard 7 ft Bud equipment cabinet during one strike. This equated
>> to some
>> 120,000 amps or roughly 720 megawatts of energy. There were several
>> new
>> holes in the cabinet after the strike. Thank goodness for remote
>> instrumentation. I don't think the engineer and his trusty Simpson
>> 260 VOM
>> would have survived.
>>
>> Just be sure that all grounds and ground sources on the property are
>>
>> connected together.
>>
>> 73
>> Bob, K4TAX
>>
>>
>> ----- Original Message -----
>> From: "Bill Rowlett" <kc4atu@hotmail.com>
>> To: <tentec@contesting.com>
>> Sent: Saturday, November 19, 2005 4:23 PM
>> Subject: Re: [TenTec] Orion 2 lightning rule
>>
>>
>> > Rule #3: UNPLUG the power supply/power strip when not in use
>> during the
>> > storm months.
>> >
>> >
>> > kc4atu
>> >
>> >
>> >>From: "Stephen M. Shearer" <wb3lgc@verizon.net>
>> >>Reply-To: Discussion of Ten-Tec Equipment <tentec@contesting.com>
>> >>To: "'Discussion of Ten-Tec Equipment'" <tentec@contesting.com>
>> >>Subject: Re: [TenTec] Orion 2 lightning rule
>> >>Date: Sat, 19 Nov 2005 12:33:04 -0500
>> >>
>> >>You asked: This is what I supplied to the insurance companies
>> (note ARRL
>> >>insurance was purchased 6 days before the strike). I was at the
>> BSA
>> >>Jamboree at the time. My wife and cat were at home at 5am when the
>> strike
>> >>hit. I had two (2) leaks in the gas stove. One was a 1/32" hole
>> in the
>> >>flex gas line.
>> >>
>> >>DETAIL of Lightning Strike:
>> >>
>> >>The lightning strike hit the center [actually one end] of the
>> WB3LGC/G5RV
>> >>antenna in the back yard and vaporized the ladder line feeding
>> both sides
>> >>of
>> >>the antenna [the steel copperweld wire was vaporized, but left the
>> plastic
>> >>jacket]. The lightning followed the coax cable to the free end of
>> the
>> >>cable
>> >>in the basement shop/radio shack. On the way to the basement,
>> the
>> >>lightning
>> >>took a side trip [blew a hole in the coax and house] to the
>> power/circuit
>> >>panel, via the house wiring. This same discharge path also found
>> the
>> >>underground cables feeding the detached garage. The circuit panel
>> had
>> >>breakers tripped for the kitchen and the bathroom. One likely
>> discharge
>> >>path, via the ground wire in the romex cable, is the kitchen
>> circuit
>> >>feeding
>> >>the stove and the path to ground via the black pipe gas line.
>> This could
>> >>[did] account for the small gas leak at the stove. In the
>> basement, the
>> >>lightning discharged through a metal workbench with a metal top
>> [the coax
>> >>was on the concrete floor]. A portable TV on top of the bench
>> became
>> >>fried
>> >>[a number of holes zapped in the bench] and the major source of
>> smoke that
>> >>set off the smoke detector in the shop and at the top of the
>> basement
>> >>stairs. The TV and everything that was plugged into the common
>> power
>> >>strip
>> >>also became "toast". The power strip fed both UPS's, a wireless
>> >>telephone,
>> >>a power supply for the Orion radio, a computer and monitor
>> [replaced with
>> >>a
>> >>nice laptop]. The final path was through the heavy ground strap
>> attached
>> >>to
>> >>the Orion radio to the 5/8" copper water line feed for the house.
>> The
>> >>phone
>> >>line in the basement is a direct feed to the office computer on
>> the second
>> >>floor.
>> >>
>> >>73, Steve WB3LGC
>> >>The Orion took its hit via the 12V power line and the case
>> (jumping from
>> >>the
>> >>workbench to the UPS to the Orion). New Lightning Rule #2;
>> Ground the
>> >>un-used coax in the shack or before it gets to the shack [it might
>> have
>> >>helped].
>> >>
>> >>-----Original Message-----
>> >>From: tentec-bounces@contesting.com
>> [mailto:tentec-bounces@contesting.com]
>> >>On Behalf Of Peter Burbank
>> >>Sent: Saturday, November 19, 2005 11:53 AM
>> >>To: Discussion of Ten-Tec Equipment; 'Discussion of Ten-Tec
>> Equipment'
>> >>Subject: Re: [TenTec] Orion 2 lightning rule
>> >>
>> >>
>> >> >
>> >> >Btw: New Lightning Rule #1; A well grounded rig will provide a
>> path for
>> >> >lightning even if the antenna coax is disconnected from (and
>> separated
>> >>from)
>> >> >the radio.
>> >> >
>> >> >73, Steve WB3LGC
>> >>
>> >>Steve, have you been able to trace the lightning path or any
>> particular
>> >>reason why
>> >>it hit your rig?
>> >>73 Pete NV4V
>> >>
>> >>
>> >>--
>> >>No virus found in this outgoing message.
>> >>Checked by AVG Anti-Virus.
>> >>Version: 7.1.362 / Virus Database: 267.13.4/175 - Release Date:
>> 11/18/2005
>> >>
>> >>
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>>
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>
>
> --------------------------------------
> Duane Calvin, AC5AA
> Austin, Texas
>
> http://home.austin.rr.com/ac5aa
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