I used my own magnetometer hooked up to a laptop and got actual magnetic 
field numbers as they occurred.  You can make one for about $100.  I do not 
have it running now, but plan to re install it in the Spring as soon as the 
ground thaws out. I buried mine in the garden to keep the temperature more 
or less constant. It also was away from any moving metal (like cars and 
lawnmowers)  I wrote it up here: 
http://www.directivesystems.com/PDF/MAGTALK.PDF
   A company in Britain makes the sensors and supplies some ASICs and PC 
boards. It makes for a fun project. It sure is obvious when a magnetic storm 
commences. I used it for predicting auroras and chasing DX on 144 MHz.
73
Dave K1WHS
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Topband Reflector
 
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