[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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