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Re: Not so stupid question



There is a very simple experiment to confirm Bob's comments:
Obtain a large nail such as a ten or 12 penny spike and tie
a thin thread near the center such that the nail balances
horizontally.  Then stroke the nail with a magnet to magnetize
the nail.  Suspend the nail in a draft free area.  With time,
the nail will point North and "dip" downwards to the North
magnetic pole.  If you happen to have a bar magnet, this
experiment becomes even simpler!  73  Cliff K7RR


On Sun, 26 Dec 1999, Robert McGwier wrote:

> 
> Ever dropped iron filings around a bar magnet in water?
> Notice that if you lay a disc on top of the magnet that
> some of the iron filings are <<NOT>> parallel to the
> surface and near the magnetic poles that are almost
> PERPENDICULAR to the surface.  The earth's magnetic
> field while not a perfect bar magnet inside a sphere is
> close enough that this mind picture should help
> establish that there is indeed an up,down, north,
> south at the surface and gets more different from
> north, south near the magnetic poles.
> 
> Bob
> 
> 
> 
> At 09:44 AM 12/26/1999 -0500, you wrote:
> > 
> >> > Is there any offset for elevation?
> >> 
> >> No. I heard of magnetic north; never heard of magnetic "up" though.
> >> 
> >
> >I realize there was some humor involved here, but actually, the programs that 
> >will give you your magnetic deviation (I have one I got from NOAA on my home 
> >page...   http://www.megalink.net/~wejones/pgeomag3.exe )
> >ask you for an altitude, which affects the results, so maybe there IS a 
> >"magnetic UP"  :-) .  I at first thought that this meant elevation above sea 
> >level, but I think it means above ground level, because it seems to work 
> >properly only if I enter zero.
> >   Anyway, it may make a difference if you are in an airplane, but not for an 
> >antenna, unless you take your compass reading at the top of a REALLY tall 
> >antenna.   :-)
> >
> >  I like the moon idea, but I prefer the sun. There are tables at 
> >http://riemann.usno.navy.mil/AA/data/docs/AltAz.html
> > (and many computer programs will give this too) 
> >that give you the azimuth of the sun for any time of day.  I usually just
> find 
> >what time the azim is 180 and go look at the direction that the shadows are 
> >falling, and that is north.
> >
> >
> >
> >
> >
> >**************************************
> >*Bill Jones  N3JLQ  Sweden Maine     *
> >* wejones@megalink.net               *
> >* http://www.megalink.net/~wejones   *
> >**************************************
> >----
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