mahaun@sactoh0.UUCP (Mark A. Haun) (10/02/89)
I am trying to build a fluxgate magnetometer sensitive enough to monitor variations in the Earth's magnetic field, mostly to observe magnetic storms caused by big flares on the sun (March 13, 1989 stuff especially :-) !). I have seen an article about one of these designed to serve as a solid state compass in Radio Electronics magazine's "Hardware Hacker" column, and Radio Shack has also recently come out with a fluxgate compass. Would such a circuit be readily adaptable for my purposes? My main concern is whether it would have enough sensitivity; I would like to measure changes at least as small as 10 gammas (.001 Gauss), and if possible, even smaller. I envision having a setup with the magnetometer hooked up to a chart recorder and running 24 hours a day. It would alert me to the start of any magnetic storms and would show me the best times to try and observe the northern lights from my location here in California, if there are more *big* flares like this past March (they were actually seen here then, but I wasn't aware of it until a few days later). I would appreciate hearing from anyone who has built any sort of fluxgate magnetometer, anyone who has seen a construction article for one, or anybody with suggestions/ideas/etc. on the feasibility of this project. Please email to any of the addresses below. Thanks! -- ( Mark A. Haun KJ6PC )( UUCP: ...ames!pacbell!sactoh0!mahaun ) ( Sac-Unix, Sacramento CA )( AMPRNET: kj6pc@kj6pc.ampr.org ) ( IP: [44.2.0.56] 144.93 Mhz )( PACKET: kj6pc@wa6nwe.#nocal.ca.usa.na ) ( INTERNET: mmsac!sactoh0!mahaun@sacto.West.Sun.COM )
vaso@mips.COM (Vaso Bovan) (10/02/89)
In article <1914@sactoh0.UUCP> mahaun@sactoh0.UUCP (Mark A. Haun) writes: > >I am trying to build a fluxgate magnetometer sensitive enough to >monitor variations in the Earth's magnetic field, mostly to observe >magnetic storms caused by big flares on the sun (March 13, 1989 >stuff especially :-) !). > >I would like to measure changes at least as small as >10 gammas (.001 Gauss), and if possible, even smaller. > ? You mean of course, nanotesla (nT), since 1954. :-)
johns@calvin.EE.CORNELL.EDU (John Sahr) (10/02/89)
In article <28601@buckaroo.mips.COM> vaso@mips.COM (Vaso Bovan) writes: >In article <1914@sactoh0.UUCP> mahaun@sactoh0.UUCP (Mark A. Haun) writes: >> >>I would like to measure changes at least as small as >>10 gammas (.001 Gauss), and if possible, even smaller. >> > >? You mean of course, nanotesla (nT), since 1954. :-) Well, I don't know about the "official" state of "gamma" vs "nT", but both are in common usage in "the business." For earth-based mags, the _only_ unit I have heard used is "gamma". How many of you circuit dweebs use the "right" term for inverse ohms? I thought so. (yearning for the days of furlongs per fortnight :*) -- John Sahr, Dept. of Electrical Eng., Cornell University, Ithaca, NY 14853 johns@{alfven,calvin}.ee.cornell.edu, {rochester,cmcl2}!cornell!calvin!johns --When the dust settles, each B2 bomber will fund NSF for more than a year--
billk@hpsad.HP.COM (Bill Katz) (10/03/89)
There is an excellent "Technical Support Package" available from NASA on
flux-gate magnetometers. It is the Technical Support Package for Tech
Brief LAR-13560, "Improved Flux-Gate Magnetometer, and includes a 23 item
bibliography. The package is about 35 pages long, and can be obtained
from NASA Langley Research Center, Hampton, VA 23665-5225. I got it from
a bingo card in _NASA Tech Briefs_ a couple years ago. I would assume it's
still available.
______________________________________________________________________________
_ /| -ACK! Bill (the) Katz Internet: billk@hpsad.hp.com
\'o.O' -PFHHHT! Hewlett-Packard UUCP: hplabs!hpsad!billk
=(___)= -COUGH! Signal Analysis Div. Phone: (707) 794-2300
U -ACK! 1212 Valley House Dr. Fax: (707) 794-4452
Rohnert Park, CA 95428
______________________________________________________________________________jmasters@pcocd2.intel.com (Justin Masters~ ) (10/03/89)
Take a look inside the November 1989 Radio Electronics. I just got mine last night and there is info for trying to build a fluxgate magnetometer. ----------------------------------------------------------------------------- Is my car the only one in America where | Justin "Ice Cream Monster" Masters someone breaks in and turns up my radio | every time I park? - Steven Wright | jmasters@pcocd2.intel.com
jgd@rsiatl.UUCP (John G. De Armond) (10/04/89)
In article <1363@calvin.EE.CORNELL.EDU> johns@calvin.spp.cornell.edu.UUCP (PUT YOUR NAME HERE) writes: > >How many of you circuit dweebs use the "right" term for inverse ohms? >I thought so. > You mean you don't sling your *ahem* Semen(s) around with wild abandon? :-) (I no, I no, it ain't spelled rite but whot the hek?) John -- John De Armond, WD4OQC | Manual? ... What manual ?!? Radiation Systems, Inc. Atlanta, GA | This is Unix, My son, You gatech!stiatl!rsiatl!jgd **I am the NRA** | just GOTTA Know!!!
rjk@sequent.UUCP (Robert Kelley) (10/07/89)
In _The_Amateur_Scientist_ section of Scientific American, Feb 1968, page 124, there's a description of a differential magnetometer capable of detecting a minimum difference in field strength of 3e-5 oersted. The magnetic field of the earth causes protons in water molecules to precess at a rate of about 2025 Hz. The article describes a device consisting of two bottles of water with coils wound around them, and a high-gain (2e6) tuned amplifier. A dc current is passed through both coils to align the magnetic dipoles, then the current is removed and the amplifier is connected to the coils. A beat frequency proportional to the difference in the magnetic fields at each bottle is heard at the output of the amplifier. It might be interesting to build a more modern version of the system described in the article. Another installation of _The_Amateur_Scientist_ describes another NMR setup and suggests adding ferric nitrate to the water. Why?
chardros@csli.Stanford.EDU (Doug Gibson) (10/08/89)
In article <22842@sequent.UUCP> rjk@sequent.UUCP (Robert Kelley) writes: >It might be interesting to build a more modern version of the system described >in the article. Another installation of _The_Amateur_Scientist_ describes another >NMR setup and suggests adding ferric nitrate to the water. Why? In the NMR lab given in undergrad p-chem here, we added a decent amount (millimolar, I think) of some ferric salt to water.... and all of a sudden, the water peak was about 1000 Hz wide. I suspect there's a connection. -Doug Gibson chardros@csli.stanford.edu "He's dead, Jim. You grab his tricorder, and I'll take his wallet."
pierson@cimnet.dec.com (10/09/89)
If the interest was in an "early warning" device for Auroral activity, a simpler option is WWV. WWV includes a solar activity report in, in voice, the 18th minute of every hour. thanks dave pierson |The facts as accurately as I can manage, Digital Equipment Corporation |The opinions, my own. 600 Nickerson Rd Marlboro, Mass 01752 pierson@cimnet.enet.dec.com
jkl141@tijc02.UUCP (John Leroy ) (10/10/89)
From article <1914@sactoh0.UUCP>, by mahaun@sactoh0.UUCP (Mark A. Haun): > > I would appreciate hearing from anyone who has built any sort of > fluxgate magnetometer, anyone who has seen a construction article > for one, or anybody with suggestions/ideas/etc. on the feasibility > of this project. > See "Absolute Measurements in Electricity and Magnetism" published by Dover Books for the theory and math behind the magnetometer described in Sky and Telescope this month. Anybody got a good reference for the fluxgate magnetometer? -- -John LeRoy Packet Radio: WA4VLV @ WX4S Compuserve: 74136,401 UUCP: rti!tijc02!jkl141 Phone: 615-461-2440
david@epicb.UUCP (David Cook) (10/13/89)
>From article <1914@sactoh0.UUCP>, by mahaun@sactoh0.UUCP (Mark A. Haun): >> >> I would appreciate hearing from anyone who has built any sort of >> fluxgate magnetometer, anyone who has seen a construction article >> for one, or anybody with suggestions/ideas/etc. on the feasibility >> of this project. >> > Mark... The very latest issue of Radio Electronics has an article on connecting the Radio Shack Electronic COmpass to a computer system. To make a long story short, they have an excellent discussion on fluxgate magnetometers as a part of the article, including a description as to how the windings are made (a control winding goes totally around the core [ring] and a sine and cosine winding exist at 90 degree angles to each other). Check out this article for at least a "feel" as to how these devices are constructed.
jkl141@tijc02.UUCP (John Leroy ) (10/14/89)
From article <1914@sactoh0.UUCP>, by mahaun@sactoh0.UUCP (Mark A. Haun): > > I am trying to build a fluxgate magnetometer sensitive enough to > monitor variations in the Earth's magnetic field, mostly to observe > magnetic storms caused by big flares on the sun (March 13, 1989 > stuff especially :-) !). > Some time back, I remember seeing an application note for Hall Effect devices used to build a simple compass. Anybody have any insight as to whether these devices might be available in a form suitable for building a magnetometer? -- -John LeRoy Packet Radio: WA4VLV @ WX4S Compuserve: 74136,401 UUCP: rti!tijc02!jkl141 Phone: 615-461-2440
jkl141@tijc02.UUCP (John Leroy ) (10/14/89)
From article <1914@sactoh0.UUCP>, by mahaun@sactoh0.UUCP (Mark A. Haun): > > I am trying to build a fluxgate magnetometer sensitive enough to > monitor variations in the Earth's magnetic field, mostly to observe > magnetic storms caused by big flares on the sun (March 13, 1989 > stuff especially :-) !). > > I would appreciate hearing from anyone who has built any sort of > fluxgate magnetometer, anyone who has seen a construction article > for one, or anybody with suggestions/ideas/etc. on the feasibility > of this project. Please email to any of the addresses below. My email to you bounces, so I'll post this. I just stumbled across "Simple Magnetometers or How to Measure Your Own K-Index" by Russell G. Wicker, W4WD in the Proceedings of the 22nd conference of the Central States VHF Society (1988). If you want a copy and can't find the proceedings let me know. -- -John LeRoy Packet Radio: WA4VLV @ WX4S Compuserve: 74136,401 UUCP: rti!tijc02!jkl141 Phone: 615-461-2440
mcdonald@aries.uiuc.edu (Doug McDonald) (10/30/89)
>> >>I would like to measure changes at least as small as >>10 gammas (.001 Gauss), and if possible, even smaller. >> > >? You mean of course, nanotesla (nT), since 1954. :-) I have been in the science business for over 20 years and have never heard anyone refer to magnetic fields in Tesla - everyone uses gauss. It is true that people know that someone somewhere created a unit of magnetic field called a Tesla, but no one remembers how many gauss are in one Tesla, and no one uses it. Sometimes it might appear in a textbook (usually directed at freshmen or sophmores - more advanced books use gauss). There are lots of names of units out there that are simply not used. (Also, I might add, a lot of people refer to actual physical magnets, though not the fields they create, in megahertz - as in "it's a 500 MHz magnet" meaning, of course, that the NMR resonance frequency of protons in it would be 500 MHz." Even the people who do this snicker a bit while doing it, however.) Doug McDonald
forbes@aries.uiuc.edu (Jeff Forbes) (10/30/89)
NMR spectroscopists refer to their magnets in proton resonance frequency as well as field in TESLA. A 500 MHz magnet is 11.7 T, a 60 MHz magnet is 1.6 T, etc. Jeff Forbes
wilkins@jarthur.Claremont.EDU (Mark Wilkins) (10/30/89)
In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu> mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes: >(Also, I might add, a lot of people refer to actual physical >magnets, though not the fields they create, in megahertz - as >in "it's a 500 MHz magnet" meaning, of course, that the NMR >resonance frequency of protons in it would be 500 MHz." Even the >people who do this snicker a bit while doing it, however.) > >Doug McDonald Ummm... In the world of analytical chemistry and in some other areas where large magnets are often in use the Tesla is used to measure large fields. For example, Nicolet Instruments, the company which currently holds the patent on Fourier transform mass spectrometers, advertises all of their magnets in Tesla values as do most other manufacturers in the analytical chemistry market. In general, when I was working in analytical chemistry at UC Riverside, the only place I heard the gauss values used was in the Bank of America's specification that credit cards were unsafe past the 50 gauss line. The magnets were always, to us, thirteen, seven, and three TESLA. Of course, everybody also used "torr" to refer to "mm Hg," which people in some fields would find odd. I suppose the point is that just because your area of work has different conventions than someone else's it isn't really yours to say that some unit or another is NEVER, EVER used. -- Mark Wilkins wilkins@jarthur.claremont.edu
irf@kuling.UUCP (Bo Thide') (10/30/89)
In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu> mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes: >>> >>>I would like to measure changes at least as small as >>>10 gammas (.001 Gauss), and if possible, even smaller. >>> >> >>? You mean of course, nanotesla (nT), since 1954. :-) > >I have been in the science business for over 20 years and have >never heard anyone refer to magnetic fields in Tesla - everyone >uses gauss. I use Tesla (or, rather, nanoTesla) all the time. But I have only been in the science business for 17 years so I had a chance to learn the SI system properly ... :-> Bo ^ Bo Thide'-------------------------------------------------------------- | | Swedish Institute of Space Physics, S-755 91 Uppsala, Sweden |I| [In Swedish: Institutet f|r RymdFysik, Uppsalaavdelningen (IRFU)] |R| Phone: (+46) 18-403000. Telex: 76036 (IRFUPP S). Fax: (+46) 18-403100 /|F|\ INTERNET: bt@irfu.se UUCP: ...!uunet!sunic!irfu!bt ~~U~~ -----------------------------------------------------------------sm5dfw
henry@utzoo.uucp (Henry Spencer) (10/30/89)
In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu> mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes: >I have been in the science business for over 20 years and have >never heard anyone refer to magnetic fields in Tesla - everyone >uses gauss... >Sometimes it might appear in a textbook (usually directed at >freshmen or sophmores - more advanced books use gauss). The gauss is the older unit, still used a lot, especially in older sources and by older writers. The Tesla is the correct modern unit; if you look around, you'll see increasing use of it in most fields. -- A bit of tolerance is worth a | Henry Spencer at U of Toronto Zoology megabyte of flaming. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu
larry@kitty.UUCP (Larry Lippman) (10/30/89)
In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu>, mcdonald@aries.uiuc.edu (Doug McDonald) writes: > >>I would like to measure changes at least as small as > >>10 gammas (.001 Gauss), and if possible, even smaller. > > > >? You mean of course, nanotesla (nT), since 1954. :-) > > I have been in the science business for over 20 years and have > never heard anyone refer to magnetic fields in Tesla - everyone > uses gauss. It is true that people know that someone somewhere > created a unit of magnetic field called a Tesla, but no one > remembers how many gauss are in one Tesla, and no one uses it. > Sometimes it might appear in a textbook (usually directed at > freshmen or sophmores - more advanced books use gauss). Speaking as a Gauss-person who would prefer to see otherwise :-), I regret to inform you that the Tesla is indeed being used in the real world to replace the Gauss as a unit of magnetic flux density measurement. Many magnetometer and magnetic instrument manufacturers, such as F. W. Bell, Humphrey Inc., FRL Industries and Walker Scientific now use the Tesla instead of the Gauss as their unit of specification. However, it is somewhat amusing to note that while these vendors still refer to certain products as "gaussmeters", they are now specified using the Tesla as a unit of measurement; sort of an oxymoron, huh? :-) Since I have already survived and coped with the Pascal, the change to Tesla was less traumatic than I had imagined. Incidently, the nanotesla (nT) seems to have replaced the gamma (.00001 Gauss) where finer magnetic flux measurements are concerned. <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {allegra|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> TEL 716/688-1231 | 716/773-1700 {hplabs|utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 | 716/773-2488 "Have you hugged your cat today?"
johns@calvin.EE.CORNELL.EDU (John Sahr) (10/30/89)
In article <1989Oct29.174631.12960@ux1.cso.uiuc.edu> mcdonald@aries.scs.uiuc.edu (Doug McDonald) writes: >>>I would like to measure changes at least as small as >>>10 gammas (.001 Gauss), and if possible, even smaller. >>? You mean of course, nanotesla (nT), since 1954. :-) >I have been in the science business for over 20 years and have >never heard anyone refer to magnetic fields in Tesla - everyone >uses gauss. It is true that people know that someone somewhere >created a unit of magnetic field called a Tesla, but no one >remembers how many gauss are in one Tesla, and no one uses it. >Sometimes it might appear in a textbook (usually directed at >freshmen or sophmores - more advanced books use gauss). [] >Doug McDonald Whoa, thea, padnuh. The "Tesla" is alive and well, thank you. If I walk over to the High Volt Lab, I find people quite comfortable with kilogauss or tesla (not the same, of course), as they torture innocent protons. Engineering textbooks through the graduate level tend to use MKS units, which include Tesla. Physics textbooks, on the other hand, tend to use cgs, which include gauss. I have several of each brand of text. For genuine pandemonium, look at plasma physics texts. In ionospheric physics, there is no standard at all, but a pretty free mix of cgs and MKS. Chen's plasma physics 1st ed was in cgs: the second is MKS. You be the judge. Actually, I prefer cgs all the way, myself, but I'm not dogmatic about it, even though it ought to be obvious that cgs units are The One True Units. On the other hand, E/B in MKS has units of velocity, which is convenient. But on the other hand, E/B in cgs has no units at all, which is also convenient. On the other hand, my Radio Shack voltmeter insists on giving me MKS units. On the other hand, Jackson is a nice reference, and uses cgs, so it must be good. So, as I said, I don't insist upon cgs, because this is a free planet. But, come the revolution, the MKSeoisie will be the first with their backs against the wall. -- John Sahr, | Electrical Engineering - Space Plasma Physics johns@alfven.spp.cornell.edu | Cornell University, Ithaca, NY 14853
firth@sei.cmu.edu (Robert Firth) (10/31/89)
In article <1425@calvin.EE.CORNELL.EDU> johns@calvin.spp.cornell.edu.UUCP (PUT YOUR NAME HERE) writes: >But, come the revolution, the MKSeoisie will be the first with >their backs against the wall. Hear hear! Not content with making us remember all kinds of silly historical names, they have now removed one of the best terms in the entire science of electromagnetism. Who ever heard of "de-Tesla-ing" ?
geller@bnlux0.bnl.gov (joseph geller) (11/14/89)
I would like to send some notes on magnetometers to mahaun@sactoh0
but, my email keeps bouncing; please send your full email address or regular
mail address to geller@bnlux0.bnl.gov or to bnl, bldg911A (ags), Upton,
NY, 11973.