Journal notes, Some Run Time with the New prototype
GELLER Labs "Backyard Science"
Thoughts on a proton precession magnetometer design - a Proton Magnetometer Project
The goal of this project is a low cost high performance proton magnetometer (a digital magnetometer) kit for amateur scientists to be able to accurately measure and monitor changes in the Earth's total magnetic F field and to observe geomagnetic storms. There is a regular daily (diurnal) variation in the Earth's magnetic field. During events related to solar activity, there can be sudden changes in the field (such as a sudden impulse) as well as large excursions in the field which can be more than ten times the regular diurnal variation caused by magnetic storms.
(be sure to hit refresh to pick up our latest changes and entries)
Sunday, May 2, 2010:
Overnight run: PDF, TXT, USGS PDF. There was a minor event this morning, probably a minor G1 storm. There is an alert. Here is a review of the magnetic storm G and geomagnetic K indices. Seems it's a G2 moderate geomagnetic storm: PDF, TXT, USGS PDF, Space Weather Now PDF.
A lot of the recent noise issues were caused by an old failing WinXP machine, pretty ironic. Still running on the Win7 desktop. Eventually will switch operations over to to a Win7 laptop near the magnetometer electronics.
evening: It continues to be a relatively active geomagnetic day: PDF, TXT, USGS PDF. Winding down now: 9:51 pm PDF.
Monday, May 3, 2010:
Overnight run: PDF, TXT, USGS PDF. good view of yesterday's moderate G2 geomagentic storm. Note how relatively small the normal Monday morning disturbances from garbage trucks are compared with the magnitude of the magnetic storm.
Tuesday, May 4, 2010:
Last few days: PDF, TXT, USGS 24 hours PDF.
Thursday, May 6, 2010:
The new "old" hp 6237B power supply arrived very DOA (loose parts inside), however after studying the manual and a several hour repair effort and a cannibalized hp AC voltmeter (for a needed transistor) it is up and running. The change over from batteries was much easier than expected. Both the analog +/- 6V supplies as well as the 1.2 Amp polarizing supply (15V in current mode) are now supplied by the triple output hp 6237B. After all the efforts related to grounding, the system is running fine with the 6237B grounded to house ground and the analog common connected to the 6237B ground. Also, changed over from the Windows 7 desktop to a Vostro laptop. All seems fine, even without using the dedicated #12 earth ground wire run last week. It continues to look like all of the noise problems were from the failing WinXp desktop machine (which has since been recycled into piles of aluminum and steel and returned to circulation via our local Empire recycling company).
The +/- 6V (can be just about anything from 6V to 15V, possibly 18V) current draw barely registers on the 6237B meter (on the order of 15 mA or less). However, I do notice a small increase to about 40 mils when the circuit is opened to the amplifier during the polarization cycle. I doubt it is damaging, but something is going on there, perhaps some of the input stages are saturating when the input is left open? This needs some more investigation later.
Afternote: May 12 picture showing repaired and operating hp 6237B power supply JPG.
Saturday, May 8, 2010:
Overnight run: PDF, TXT, USGS PDF. possibly returning to a quiet day to two. It looks like the beginning of a "normal" diurnal cycle this am. Seems like there are more auto-retries than before, possibly the laptop is injecting some more noise than the relatively distant desktop. Otherwise, the system appears to be running fine.
Sunday, May 9, 2010:
Overnight run: PDF, TXT, USGS PDF. The diurnal cycle has returned following last weeks moderate geomagnetic storm. The plots (pdfs) are not quite as nice for some reason from laptop. Later, funds allowing, I probably need to buy an inexpensive dedicated desktop for the magnetometer. Working on a proof of principle interlock for the situation where the program stops during the couple of seconds that the polarization coil is powered. I am using an ancient meter relay so I can watch it in operation, but a production circuit would just be a handful of parts.
Monday, May 10, 2010:
Last few days: PDF, TXT, 24 hour USGS PDF. The 5/9/10 offset about noon was from a group of cars parked nearby.
Project Documentation (very early stages)
QUESTIONS/COMMENTS/notice of typos, etc. send email to joegeller @ gellerlabs dot com
COPYRIGHT © 2009, 2010 JOSEPH M. GELLER, All rights reserved.