Xref: utzoo comp.dcom.modems:3931 sci.physics:8356
Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!gatech!galbp!wittsend.LBP.HARRIS.COM!mhw
From: mhw@wittsend.LBP.HARRIS.COM (Michael H. Warfield (Mike))
Newsgroups: comp.dcom.modems,sci.physics
Subject: Re: TrailBlazer Plus vs. lightning
Message-ID: <7994@galbp.LBP.HARRIS.COM>
Date: 31 May 89 16:28:58 GMT
References: <3784@phri.UUCP>
Sender: news@galbp.LBP.HARRIS.COM
Reply-To: mhw@wittsend.UUCP (Michael H. Warfield (Mike))
Organization: Harris/Lanier Network Knitting Circle
Lines: 33

In article <3784@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:

>	My physics question about all this is, what was the click I heard?
>I thought it was just the phone line relay, but my wife, in the next room,
>claims to have heard it too (the relay is *far* too soft for that).  Does
>up-close lightning make a >click< just before the *BA-ROOOM*?

	Just as a fast guess it was probably inductive pick-up directly into
the Trailblazer speaker (if that's where you heard it from) or possibly from
d*mn near anything capable of picking up a magnetic field and generating
mechanical motion.  Several years ago I was a broadcast supervisor at a
Mid-West NBC-TV affiliate.  One evening we where having a "dry-lightening"
storm in the area.  Lightening strikes were occuring in the 5 to 10 mile
range by timing the thunder (you know count the seconds and divide by 6).
I was outside the transmitter building during a short power outage.  Every
time a lightening flashed inside a 10 mile radius, the guy wires on our 1,000
foot tower would "hiss" and "click".  Since the tower was VERY well grounded
and the lightening was a fair distance away (none less than five miles or I
wouldn't have been OUTSIDE!), I discounted the possiblity of local static
discharge and figured it to be some sort of inductive or electromagnetic
effect.

	If the lightening was as close as you say, you're probably lucky the
click wasn't from thermal expansion as your modem melted its case :-).  I
have seen lightening and its effects, up close, TOO OFTEN, and I know one
thing for sure.  You cannot predict just what it is going to do or what
peripheral effects it can have!  The magnetic fields around that tremendous
current pulse alone are staggering!

Michael H. Warfield  (The Mad Wizard)	| gatech.edu!galbp!wittsend!mhw
  (404)  270-2123 / 270-2098		| mhw@wittsend.LBP.HARRIS.COM
An optimist believes we live in the best of all possible worlds.
A pessimist is sure of it!