Towertalk
[Top] [All Lists]

[TowerTalk] Fwd: Fwd: Near Field Lightning Damage

To: towertalk@contesting.com
Subject: [TowerTalk] Fwd: Fwd: Near Field Lightning Damage
From: Hans Hammarquist via TowerTalk <towertalk@contesting.com>
Reply-to: Hans Hammarquist <hanslg@aol.com>
Date: Tue, 21 Apr 2015 22:58:38 -0400
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Patrick,


1980 I had just finished installing shielding and rewiring a 66,000 square feet 
research building in order to minimize the EMI/RFI problems that existed in the 
building when it was just finished. Not that is has much to do with EMP effects 
on digital watches.


I do know that the radio spectrum from the EMP is much wider (contains higher 
frequencies) than the spectrum from a lightning strike. It is hard for me to 
understand that a digital watch can be destroyed without the wearer being 
severely medically affected such as external and/or internal burn damages.


Well, I wasn't there to see it myself so ...


Hans - N2JFS 



-----Original Message-----
From: Patrick Greenlee <patrick_g@windstream.net>
To: towertalk <towertalk@contesting.com>
Sent: Sun, Apr 19, 2015 10:11 pm
Subject: Re: [TowerTalk] Fwd:  Near Field Lightning Damage


Well Hans, I was there when the vessel made port (about 1980.) Where 
were you?
I took a sabbatical from my usual employ and worked for a 
short while in field
service engineering for two San Diego based firms, 
Marine Electric and Honor
Marine.  I held a commercial radiotelephone 
lisc with ship's RADAR
endorsement.

Being suspicious and skeptical of an anecdotal retelling of a
once upon 
a time tale is a trait we share but I personally would avoid calling
a 
witness to the fried equipment a liar by any means, however indirect.

Oh,
and these digital watches were  not metal encapsulated on the side 
where the
wearer was intended to view the readout.

Admittedly this was a one off
occurrence in the collective experience of 
the waterfront electronics types I
talked with about the event.  Much 
more common was to lose goniometers in RDF
equipment due to antenna 
position (highest point aboard but usually not much
else.

Patrick   NJ5G

On 4/19/2015 2:44 PM, Hans Hammarquist via TowerTalk
wrote:
> This sounds very anecdotal. Yes, a near strike lightning may take out
CB radios etc but that it took out digital watches make me suspicious. The are
usually metal encapsulated and very immune to external field. I believe a EMP
strong enough to take out a watch also will take out the person carrying that
watch.
>
>
> Depending on the grid size, a Faraday cage is useful for the EM
from a lightning as the "M" will introduce back EMF in the cage which will
neutralize the "M".
>
>
> I hope the "falme" will not be too long,
>
>
>
Hans - N2JFS
>
>
>
> -----Original Message-----
> From: Patrick Greenlee
<patrick_g@windstream.net>
> To: towertalk <towertalk@contesting.com>
> Sent:
Sat, Apr 18, 2015 10:18 pm
> Subject: Re: [TowerTalk] Near Field Lightning
Damage
>
>
> Back in the 80's a tuna boat pulled into San Diego with every
device on
> board
> containing a semi-conductor inoperative.  CB radio, Marine
VHF,
> SSB, SONAR,
> RADAR, VHS tape player, SatNav LORAN, and on and on... 
All
> the crew members
> wore digital watches which were all totally
dead.
>
> One near miss by a large
> lightning stroke took out everything
with solid
> state semiconductor junctions.
> The good news was they didn't
have a
> spotter chopper aloft at the time
> dependent on the aircraft beacon
band
> transmitter on board to find the boat
> (helipad is the roof of the
pilot
> house.)  We theorized it was the EMP that
> ate everything as there
was no
> evidence that the bolt hit the boat.
>
> Later
> when asked what
could be done to provide an immune backup comm
> radio we told
> them a mu
metal box.  A Faraday cage wouldn't stop the
> magnetic pulse.
>
> Just
> a
thought in case there are any serious preppers in our midst.
>
> Patrick
>
NJ5G
> _______________________________________________
>
>
>
>
_______________________________________________
> TowerTalk
> mailing
>
list
> TowerTalk@contesting.com
>
http://lists.contesting.com/mailman/listinfo/towertalk
>
>   
>
_______________________________________________
>
>
>
>
_______________________________________________
> TowerTalk mailing list
>
TowerTalk@contesting.com
>
http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________



_______________________________________________
TowerTalk
mailing
list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

 
_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk

<Prev in Thread] Current Thread [Next in Thread>