Build a Geomagnetic Observatory ! GELLER Labs "Backyard Science"
Thoughts on a proton precession magnetometer design - a Proton Magnetometer Project. Build an Earth's field magnetometer.
The FDM MAGNETOMETER1 project is a low cost high performance proton magnetometer (a digital magnetometer) kit under development for universities and amateur scientists to be able to accurately measure and monitor changes in the Earth's total magnetic F field and to observe geomagnetic storms. Magnetic storms can cause large excursions in the field and are of concern to interests ranging from electrical power grids, radio communications, and satellite operations, to aurora watchers and amateur radio operators.
1 Filter Diagonalization Method "FDM" (harmonic inversion), see Jan 21 and Jan 23 entries, based on: Vladimir A. Mandelshtam, Howard S. Taylor, Harmonic inversion of time signals and its applications, Journal of Chemical Physics (1997), Volume 107, Issue 17, 1997, Pages 6756-6769
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Project Documentation, Links and References (very early stages)
Journal Notes:
Monday, May 23, 2011
Tuesday, May 24, 2011
Wednesday, May 25, 2011
In the peak envelope voltage (PEV) servo polarization controller mode, the polarization pulse width (polarization time) is varied automatically to maintain a relatively constant NMR free induction decay (FID) signal amplitude (as measured by PEV). This graph shows the depression of the FID signal amplitude (the FID peak envelope voltage) with the increasing ambient temperature of a warm sunny afternoon. Some of the dips in the temperature curves were caused by shading by nearby trees. The peak envelope voltage servo was turned off (about point 3900) and the polarization time was set to a fixed 0.9 second polarization time PDF. Thereafter, the PEV fell from the regulated 0.85 V value to below 0.7 V with a fluid temperature change of about 20 F. Fluid temperature was calculated from measured NMR Tau 2 values. The amplitude change for the delta 20 F temperature range is specific to the operating range on the exponential polarization curve (the population or percentage of spin alignment achieved, related to Tau 1) and its sensitivity to temperature (Tau 1 as a function of temperature) for a given type of NMR fluid.
Thursday, May 26, 2011
Overnight: PDF, TXT. The polarization curves from overnight show how the PEV (closed loop) servo held a desired 0.85 V FID amplitude overnight after being switched from a period of fixed polarization time (0.9 seconds) operation (between about points 3900 and just after 4200) back to the PEV servo mode PDF.
Friday, May 27, 2011 - Active Geomagnetic Field
Overnight: PDF, TXT. The geomagnetic field has been unsettled at times. Afternoon: The field is unsettled, possibly headed for active (sub-storm levels of activity) PDF, NOAA Wing Kp model (~4:30 pm local, UTC -4) PDF. 5:14 pm magnetogram PDF. 10 pm (unfortunately there were a number of vehicle offsets, however they are easy to see) PDF NOAA SWN PDF, the aurora oval appears to be extending well into North American this evening, including the northern US PDF. 11:30 pm PDF.
Saturday, May 28, 2011 - G2 Geomagnetic Storm! Summary View PDF
Overnight: PDF, TXT, NOAA SWN PDF, NOAA Wing Kp PDF , USGS US Observatory magnetograms PDF, NRCan Status PDF, NRCan Canadian observatory magnetograms Ottowa (OTT) PDF. Late morning PDF. Early afternoon PDF, NOAA K index PDF. 1:13 pm local (1713 UTC), this event seems to be winding down PDF. Another almost sinewave like pulse about 6 pm local PDF. NOAA magnetic (geomagnetic) storm "G" scale (G1 to G5) definitions. Note that we changed vertical scales on Saturday from our normal 100 nT range to a 200 nT range.
Sunday, May 29, 2011 - G1 Geomagnetic Storm!
Overnight: PDF, TXT Another storm (minor G1) after midnight local this morning (after 0400 UTC). In this two day magnetogram, compare yesterday's G2 magnetic storm to the G1 minor storm this morning. While half the amplitude, the similarity of shape is interesting PDF. NOAA K PDF, Wing Kp PDF, NOAA Space Weather Alerts PDF. Early afternoon: The geomagnetic field remains quite active (albeit, for now, at sub-storm levels) PDF, Wing Kp PDF. There is a new warning NOAA Alert PDF. Early afternoon (~1800 UTC) back to a minor G1 magnetic storm PDF. 1845 UTC PDF. 0240 UTC quiet returns PDF. Looking back: NOAA K PDF, Wing Kp PDF.
Want to build your own FDM Proton Precession Magnetometer? - Just a reminder, if someone would like to build a FDM magnetometer as a geomagnetic observatory before kits come out, possibly next year some time, we can put together a kit of all parts for the NBLNA and SWCTRL modules. The kit includes the aluminum boxes (not drilled), all electronic parts, and the PCBs for the two modules. The price is $300 each kit (which includes both the NBLNA and SWCTRL parts), plus shipping. (International shipping declares $300 on the customs forms, no "gifts"). There would be a two to four week delay to order more of the latest version of both PCBs (which is where we left off when project parts buying funds went critically low). The kits include only all parts to build the two modules, everything else is supplied by the experimenter as home brew (e.g. power supplies) or as surplus or new commercial buys. Coils, wire, cable, computer, power supplies, PVC parts, wood stand parts, are not included. The present version of our Windows 7 software is included (only with a kit purchase). All docs are here on the website. Reasonable tech support by email is included. We do not at this time sell assembled units or portable versions. The computer does not need to be dedicated to the project and can run other programs while running your FDM PPM observatory (as it is running on this machine as I make this entry). Buyers during this pre-production period will receive free software updates as they become available. (Note, this is an advanced project, less suitable for first time kit builders or those without experience in electronics. An inexperienced kit builder might team up with an experienced local engineer, EE professor, electronics technician, or ham radio operator with construction experience.)
Project Documentation, Links and References (very early stages)
QUESTIONS/COMMENTS/notice of typos, etc. send email to joegeller @ gellerlabs dot com
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