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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Duane Calvin, AC5AA
Austin, Texas
http://home.austin.rr.com/ac5aa
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