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Re: [TowerTalk] Fwd: Fwd: Near Field Lightning Damage

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Fwd: Fwd: Near Field Lightning Damage
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Wed, 22 Apr 2015 05:06:31 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
An EMP, is a magnetic pulse of high intensity, but of little duration. With semiconductors, it's the voltage generated by the magnetic pulse tat causes the semiconductors to fail. Semiconductor junctions are frail, or fragile if you will. Just handling them can cause elaborate junctions to fail without the user feeling a thing.

I worked in the Semiconductor industry for over 26 years, then earned a Bachelors degree in CS, started on my masters, when a good job put me back to earning a decent wage although as a GA in CS I had a higher pay than many out in the work force. Then worked with computers for another 7 years and retired as a Computer Systems project manager.

We often had computers near ultra strong magnetic fields which did not bother the computers although I can't say the same for the Hard Drives.

I wasn't there, but based on my background, I can see an EMP causing the failure of circuits without the user even being aware. OTOH in the cases sited, it was most likely induced voltage causing sensitive devices to fail. EMPs are a very complex phenomena

Lightening EMP: https://en.wikipedia.org/wiki/Electromagnetic_pulse

The initial pulse would cause relatively high voltages with each successive cycle causing less. https://en.wikipedia.org/wiki/Electromagnetic_pulseAgain the pulse can generate extremely high voltages that can reach 50,000 volts per meter, but over a short range unlike the nuclear generated EMP.

I believe lightening can generate a more localized EMP in the E2 class more powerful than a nuclear device...discounting the possibility of devices that can produce super EMTs.

73

Roger (K8RI)


On 4/21/2015 11:11 PM, Hans Hammarquist via TowerTalk wrote:
Patrick,


You must be a lucky guy or be living in a no or low lightning zone. I can't 
count the number of CB radios my friends (I never owned a CB radio for some 
reason) had to repair/replace due to indirect lightning strikes and in a few 
cases direct hit on the CB antennas. I also have a few SWR bridges where the 
reflect diode burnt out from lightning induced power.


Hans - N2JFS


-----Original Message-----
From: Patrick Greenlee <patrick_g@windstream.net>
To: towertalk <towertalk@contesting.com>
Sent: Sun, Apr 19, 2015 10:15 pm
Subject: Re: [TowerTalk] Fwd:  Near Field Lightning Damage


Bill, in so doing you would be just as wrong as Hans.  Re the CB
comment.  To
my knowledge we never replaced a CB for lighting causes.

Patrick   NJ5G

On
4/19/2015 7:33 PM, Bill Aycock wrote:
Hans is right, if a little too gentle.
I would have called the tale
"manufactured" on "Invented" rather than
"Anecdotal".
Bill--W4BSG


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73

Roger (K8RI)


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