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From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
References: <4E292DA4.3090507@telus.net> <4E294BFF.4030700@iup.uni-heidelberg.de> <E1Qm7qT-0003Xw-7x@post.thorcom.com>
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Date: Thu, 28 Jul 2011 00:29:53 +0100
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Subject: LF: Re: Lightning Story
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Dear Bill, LF Group,

It seems that a lightning strike has a current of 10s to 100s of 
kiloamperes, with a rise time measuresd in kiloamps per microsecond, so the 
transient E and H fields must be intense. I guess anything with a 
substantial length of cable attached is going to be subjected to large 
induced voltages and current, even without any connections, metallic or via 
an arc of some sort. From your description, the loop antenna has a 
relatively long feeder compared to the mini-whip, and this feeder would have 
acted as the larger side of an asymmetrical dipole "transient antenna", the 
loop itself being the other side. So perhaps the poor old TL084 had to 
endure a big transient induced between its input and output, while the 
protection diodes only had to suffer the transient induced in the loop 
itself.

On the bright side, TL084s are quite reasonably priced fuses, so perhaps an 
IC socket would be the best investment ;-)

Cheers, Jim Moritz
73 de M0BMU