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

Tue Sep 15 13:24:25 EDT 2020

Jules - the mag is under test at this moment. Hopefully, I can give some
updates soon.

[image: 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 • (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> 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.
>
>
>
> [image: 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 • (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>
> 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> 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>
>>> 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> 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!!
>>>>>
>>>>>
>>>>> [image: 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 • (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> 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> 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
>>>>>>>
>>>>>>> [image: 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 • (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> 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>
>>>>>>>> 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> 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> wrote:
>>>>>>>>>>
>>>>>>>>>>> I don't believe that my previous post carried the file K2KGJ
>>>>>>>>>>> provided.
>>>>>>>>>>>
>>>>>>>>>>> ---------- Forwarded message ---------
>>>>>>>>>>> From: Julius Madey <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>, David Witten <
>>>>>>>>>>> wittend at wwrinc.com>, Dr. Nathaniel A. Frissell Ph.D. <
>>>>>>>>>>> nathaniel.frissell at scranton.edu>, Dave Larsen <
>>>>>>>>>>> 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
>>>>>>>>>>>
>>>>>>>>>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> --
>>>>>>>>>> ----
>>>>>>>>>> Phil Erickson
>>>>>>>>>> phil.erickson at gmail.com
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> ----
>>>>>>>> Phil Erickson
>>>>>>>> phil.erickson at gmail.com
>>>>>>>> --
>>>>>>>> TangerineSDR mailing list
>>>>>>>> TangerineSDR at lists.tapr.org
>>>>>>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> --
>>>>>> ----
>>>>>> Phil Erickson
>>>>>> phil.erickson at gmail.com
>>>>>>
>>>>>
>>>>
>>>> --
>>>> ----
>>>> Phil Erickson
>>>> phil.erickson at gmail.com
>>>>
>>>
>>
>> --
>> ----
>> Phil Erickson
>> phil.erickson at gmail.com
>>
>
>
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