PSN-L Email List Message

Subject: Re: ULF
From: "meredith lamb" mlamb1@..........
Date: Wed, 27 Dec 2000 13:26:05 -0800

Arie Verveer wrote:

> Hi, In Larry's event folder are two files 001225a.au2, 001225a.au4 that
> show the ULF magnetic background and a seismic trace of the Mb5.8 event
> 1231Km south of my location. The magnet trace for that day shows some
> solar interaction. Though the trace shown here is the only long wave
> magnetic variations for that day. Its interesting to ponder if this is
> associated in some way. Maybe a precursor or a trigger or just a
> coincidence.

Hi Arie,

I did check Guam and Boulder, Colorado....they did show a
beginning solar geomagnetic signal for the time of your
geomagnetic gram, but it was a long slow variation over a
much longer period of time....then it fluxed around abit for
hours thereafter.

I've little or no background experience with your magnetometer
coil seems to cough up some questions
for more simpler designs....whether its practical or not.  Perhaps
you or someone else can interject the fallacy of my thoughts:

Would it be worthwhile to use, say, a number of coils (relay
or what not), into a number of parallel hookups, with say a steel
rod through the center holes.  Presume a low overall
resistance would be better than a high overall resistance. 
One might wrap MU foil over or around the rod to enhance its
properties...or to close any coil/rod gap?

Would it make a difference to say use a separate overhead
or side shield/s separate from the instrument for some local
prevention of some electromagnetic noise sources?  Kind of
like a parbolic antenna pointing downward to pickup the
earths signal reaction and not primarily the solar activity

Presume the coil ROD is electrically insulated from earth, it?

Just musings,

Regards, Meredith Lamb


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Larry Cochrane <cochrane@..............>