[TangerineSDR] Fwd: another 24hour RM3100 run and comparison with Fredericksburg

Julius Madey hillfox at fairpoint.net
Tue Sep 15 15:20:36 EDT 2020


Hyomin, that's good news.  I know you've been busy.   I also have to 
check alignment of the in ground RM3100; the PVC pipe may have shifted 
slightly as the soil around it settles.  When first installed, the Yaxis 
was almost zero but is now a bit off; the Z axis may be slightly off as 
well ... alignment was using a spirit level on a machinist's square.


On 9/15/2020 1:24 PM, Kim, Hyomin wrote:
> Jules - the mag is under test at this moment. Hopefully, I can give 
> some updates soon.
>
>
>
> NJIT logo <https://www.njit.edu/> 	*Hyomin Kim*
> Assistant Professor
> Physics
> Center for Solar-Terrestrial Research
> Institute for Space Weather Sciences
> hmkim at njit.edu <mailto:hmkim at njit.edu> • (973) 596-5704
> https://web.njit.edu/~hmkim/
> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>
>
>
> On Tue, Sep 15, 2020 at 12:43 PM Julius Madey <hillfox at fairpoint.net 
> <mailto:hillfox at fairpoint.net>> wrote:
>
>     The Z axis reading is high relative to the Z axis value of
>     48,032.0nT from the World Magnetic Model for that day for my
>     specific location of 42deg 15min 41.24sec North, 73deg 32min
>     32.43sec West, 1220 ft elevation.
>
>     Hyomin, have you had time to complete the solenoid coil
>     measurement of the RM3100?
>
>     Jules - K2KGJ
>
>
>     On 9/15/2020 11:58 AM, Kim, Hyomin wrote:
>>     Just to add to Phil's comments, what I see from the Z axis (if I
>>     am not wrong), is that there is a drift (whether real or not) in
>>     our Z axis data: for example, Bz in the USGS mag began at ~0 nT
>>     and ended at ~0 nT whereas ours began at ~49980 nT and ended at
>>     50000 nT, which is a 20 nT increase.
>>
>>
>>
>>     NJIT logo <https://www.njit.edu/> 	*Hyomin Kim*
>>     Assistant Professor
>>     Physics
>>     Center for Solar-Terrestrial Research
>>     Institute for Space Weather Sciences
>>     hmkim at njit.edu <mailto:hmkim at njit.edu> • (973) 596-5704
>>     https://web.njit.edu/~hmkim/
>>     104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>
>>
>>
>>     On Tue, Sep 15, 2020 at 11:53 AM Phil Erickson
>>     <phil.erickson at gmail.com <mailto:phil.erickson at gmail.com>> wrote:
>>
>>         Hi David,
>>
>>           When I say "secular change", I meant the time scale of the
>>         change.  Secular = long term, in this case relative to the
>>         time scales of a magnetic disturbance.  For example, storm
>>         time current variations might occur on a few minute to hour
>>         or two scale, but would not last for 24 hours.  The latter is
>>         what I was referring to and indicates a more long term
>>         drift.  If you saw that drift for example from day to day,
>>         that is now climatology (not weather) and you would have to
>>         see whether that is reasonable geophysically.
>>
>>         73
>>         Phil
>>
>>         On Tue, Sep 15, 2020 at 11:50 AM David Witten
>>         <wittend at wwrinc.com <mailto:wittend at wwrinc.com>> wrote:
>>
>>             Phil, Hyomin,
>>
>>             I believe that I understand your comments, but to be
>>             sure, may I ask exactly what is meant by 'secular
>>             change'.  I do not want to make incorrect assumptions
>>             about a term of art.
>>
>>             Dave
>>
>>             On Tue, Sep 15, 2020 at 10:45 AM Phil Erickson
>>             <phil.erickson at gmail.com
>>             <mailto:phil.erickson at gmail.com>> wrote:
>>
>>                 If it is picking up a 10 nT level secular change,
>>                 that is fabulous for a reasonable cost sensor!  Maybe
>>                 Jules has a ground induced current nearby?  Anyhow,
>>                 temperature sensitivity at a more precise level is
>>                 I'm sure all part of the calibration needs, so we'll
>>                 find out later...
>>
>>                 Phil
>>
>>                 On Tue, Sep 15, 2020 at 11:40 AM Kim, Hyomin
>>                 <hmkim at njit.edu <mailto:hmkim at njit.edu>> wrote:
>>
>>                     Ah, yes I agree - the secular change seems to be
>>                     a little off. I paid more attention to the small
>>                     scale variations which look to be similar. This
>>                     is a mystery to me. Maybe our sensor is not so
>>                     precisely calibrated, say, to ambient temperature
>>                     or something? Or we found another magnetic
>>                     anomaly near where Jules lives!!
>>
>>
>>                     NJIT logo <https://www.njit.edu/> 	*Hyomin Kim*
>>                     Assistant Professor
>>                     Physics
>>                     Center for Solar-Terrestrial Research
>>                     Institute for Space Weather Sciences
>>                     hmkim at njit.edu <mailto:hmkim at njit.edu> •
>>                     (973) 596-5704
>>                     https://web.njit.edu/~hmkim/
>>                     104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>
>>
>>
>>                     On Tue, Sep 15, 2020 at 11:34 AM Phil Erickson
>>                     <phil.erickson at gmail.com
>>                     <mailto:phil.erickson at gmail.com>> wrote:
>>
>>                         Hi Hyomin,
>>
>>                          You have a more expert eye than I do, so I
>>                         read your statements as "uncalibrated axes",
>>                         which of course is entirely correct for this
>>                         RM3100 data.  I just don't know how to
>>                         separate the geophysical (latitudinal
>>                         difference) from the instrumental (positional
>>                         axes are not exactly the same).  I was
>>                         reacting mostly to the 24 hour secular change
>>                         in each component.  Is it reasonable to
>>                         assume that is much less sensitive for
>>                         horizontal vs vertical components?
>>
>>                         73
>>                         Phil
>>
>>                         On Tue, Sep 15, 2020 at 11:27 AM Kim, Hyomin
>>                         <hmkim at njit.edu <mailto:hmkim at njit.edu>> wrote:
>>
>>                             Hi Phil,
>>                             At a first glance I thought the Z traces
>>                             matched well as the relative values
>>                             appear to be similar in that axis. If I
>>                             am not wrong, Bz is oriented toward the
>>                             center of the earth for the USGS mags. I
>>                             believe the USGS mag is quite precisely
>>                             oriented whereas our mag is not. Thus any
>>                             slight offset in orientation can be seen
>>                             noticeably as Bz has the biggest values?
>>                             Also, the latitudinal difference between
>>                             his place and Fredericksburg could be
>>                             another factor?
>>
>>                             Hyomin
>>
>>                             NJIT logo <https://www.njit.edu/>
>>                             *Hyomin Kim*
>>                             Assistant Professor
>>                             Physics
>>                             Center for Solar-Terrestrial Research
>>                             Institute for Space Weather Sciences
>>                             hmkim at njit.edu <mailto:hmkim at njit.edu> •
>>                             (973) 596-5704
>>                             https://web.njit.edu/~hmkim/
>>                             104 Tiernan Hall, 161 Warren Street,
>>                             Newark, NJ 07102
>>
>>
>>
>>                             On Tue, Sep 15, 2020 at 10:39 AM Phil
>>                             Erickson via TangerineSDR
>>                             <tangerinesdr at lists.tapr.org
>>                             <mailto:tangerinesdr at lists.tapr.org>> wrote:
>>
>>                                 Hi Dave,
>>
>>                                   The X and Y traces return after 24
>>                                 hours to nearly the same relative
>>                                 value in both the reference and
>>                                 RM3100 traces.  The Z trace does
>>                                 not.  Ionospheric currents flowing in
>>                                 the E region should not affect Z
>>                                 exclusive of X and Y under most any
>>                                 geometry I can think of, so I
>>                                 wondered whether the uncalibrated
>>                                 RM3100 was likely causing this.  (I
>>                                 have never professionally calibrated
>>                                 a magnetometer, so Hyomin might need
>>                                 to comment here.). In other words, I
>>                                 always assume there is some
>>                                 measurement systematic until it has
>>                                 been completely ruled out before
>>                                 assigning it to geophysical variation.
>>
>>                                 73
>>                                 Phil W1PJE
>>
>>
>>
>>                                 On Tue, Sep 15, 2020 at 10:34 AM
>>                                 David Witten <wittend at wwrinc.com
>>                                 <mailto:wittend at wwrinc.com>> wrote:
>>
>>                                     @Phil,
>>
>>                                     Correlation is great, and surely
>>                                     some further calibration issues
>>                                     may remain. But these sensors are
>>                                     NOT colocated - (200-300+ mi
>>                                     apart?) .  Wouldn't it be
>>                                     suspicious if they did correlate
>>                                     perfectly? If they did,
>>                                     shouldn't  we ask if we do really
>>                                     need an extensive array of these
>>                                     sensors? Presumably there will
>>                                     always be some local variation at
>>                                     this scale?  (don't know, just
>>                                     asking)
>>
>>                                     Dave Witten, KD0EAG
>>
>>                                     On Tue, Sep 15, 2020 at 7:21 AM
>>                                     Phil Erickson
>>                                     <phil.erickson at gmail.com
>>                                     <mailto:phil.erickson at gmail.com>>
>>                                     wrote:
>>
>>                                         Hi all,
>>
>>                                           There appears to be a 10 nT
>>                                         drift in the Z component for
>>                                         the RM3100 that is not in the
>>                                         Fredericksburg traces.  Is
>>                                         that slow systematic bias
>>                                         expected? Maybe things are
>>                                         not calbrated over that time
>>                                         frame quite yet?
>>
>>                                         73
>>                                         Phil W1PJE
>>
>>                                         On Mon, Sep 14, 2020 at 10:49
>>                                         PM David Witten via
>>                                         TangerineSDR
>>                                         <tangerinesdr at lists.tapr.org
>>                                         <mailto:tangerinesdr at lists.tapr.org>>
>>                                         wrote:
>>
>>                                             I don't believe that my
>>                                             previous post carried the
>>                                             file K2KGJ provided.
>>
>>                                             ---------- Forwarded
>>                                             message ---------
>>                                             From: *Julius Madey*
>>                                             <hillfox at fairpoint.net
>>                                             <mailto:hillfox at fairpoint.net>>
>>                                             Date: Mon, Sep 14, 2020
>>                                             at 4:26 PM
>>                                             Subject: another 24hour
>>                                             RM3100 run and comparison
>>                                             with Fredericksburg
>>                                             To: Kim, Hyomin
>>                                             <hmkim at njit.edu
>>                                             <mailto:hmkim at njit.edu>>,
>>                                             David Witten
>>                                             <wittend at wwrinc.com
>>                                             <mailto:wittend at wwrinc.com>>,
>>                                             Dr. Nathaniel A. Frissell
>>                                             Ph.D.
>>                                             <nathaniel.frissell at scranton.edu
>>                                             <mailto:nathaniel.frissell at scranton.edu>>,
>>                                             Dave Larsen
>>                                             <kv0s.dave at gmail.com
>>                                             <mailto:kv0s.dave at gmail.com>>
>>
>>
>>                                             All,
>>                                             I was hoping to record a
>>                                             relatively short term
>>                                             event but missed one
>>                                             about 10 days ago. 
>>                                             However, there was a good
>>                                             run on the 12th with an
>>                                             ~30nT excursion on the Y
>>                                             axis lasting about an
>>                                             hour.  In the attached
>>                                             pdf, the three axes of
>>                                             the RM3100 again track
>>                                             the Fredericksburg
>>                                             magnetometer station data
>>                                             quite closely.  The
>>                                             RM3100 plotted data
>>                                             points are simple running
>>                                             60second averages and not
>>                                             the more complex
>>                                             filtering algorithm used
>>                                             by Intermagnet stations
>>                                             for their 1 minute data
>>                                             points.
>>
>>                                             The vertical axes scales
>>                                             on all plots are as close
>>                                             as I could match them by
>>                                             eye in cutting and pasting.
>>
>>                                             I believe the value to
>>                                             the right on the
>>                                             Intermagnet plot is the
>>                                             mean for the 24 hour
>>                                             period.  I did not try to
>>                                             compute a 24 hour mean.
>>
>>                                             One of the products for
>>                                             the future for general
>>                                             interest would be a
>>                                             running plot like those
>>                                             available on
>>                                             Intermagnet.org. I guess
>>                                             we can dream a bit.
>>
>>                                             Jules - K2KGJ
>>                                             -- 
>>                                             TangerineSDR mailing list
>>                                             TangerineSDR at lists.tapr.org
>>                                             <mailto:TangerineSDR at lists.tapr.org>
>>                                             http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>
>>
>>
>>                                         -- 
>>                                         ----
>>                                         Phil Erickson
>>                                         phil.erickson at gmail.com
>>                                         <mailto:phil.erickson at gmail.com>
>>
>>
>>
>>                                 -- 
>>                                 ----
>>                                 Phil Erickson
>>                                 phil.erickson at gmail.com
>>                                 <mailto:phil.erickson at gmail.com>
>>                                 -- 
>>                                 TangerineSDR mailing list
>>                                 TangerineSDR at lists.tapr.org
>>                                 <mailto:TangerineSDR at lists.tapr.org>
>>                                 http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>
>>
>>
>>                         -- 
>>                         ----
>>                         Phil Erickson
>>                         phil.erickson at gmail.com
>>                         <mailto:phil.erickson at gmail.com>
>>
>>
>>
>>                 -- 
>>                 ----
>>                 Phil Erickson
>>                 phil.erickson at gmail.com <mailto:phil.erickson at gmail.com>
>>
>>
>>
>>         -- 
>>         ----
>>         Phil Erickson
>>         phil.erickson at gmail.com <mailto:phil.erickson at gmail.com>
>>
>

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