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
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