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

[John Gibbons]

All,

I have not kept up on this thread due to other commitments, but I don't see
any mention of the temperature data and plotting correlated to the data
acquisition of the 3 axis magnetometer (or more likely I missed it).

I believe that the RM3100 uses ferrite core inductors for the 3 axis
magnetic pickups and ferrites definitely have a tempco (voice of
experience...). Even a 1 Deg C may have an impact on the mu of the ferrite
at the 1nT measurement levels.

You've probably already done this (if so please point me to it) but has
this been looked at / tested for / quantified?

John N8OBJ

John C. Gibbons
Director - Sears Undergraduate Design Laboratory
Dept. of Electrical Engineering and Computer Science
Case Western Reserve University
10900 Euclid Ave, Glennan 314
Cleveland, Ohio  44106-7071
Phone (216) 368-2816 <216-368-2816> FAX (216) 368-6888 <216-368-6888>
E-mail: jcg66 at case.edu



On Mon, Sep 21, 2020 at 4:18 PM Julius Madey via TangerineSDR <
tangerinesdr at lists.tapr.org> wrote:

> Forgot to mention that one thing to keep in mind is the difference in raw
> data processing between the absolute value sliding 1minute average plots I
> do with a spreadsheet with the more complex algorithm delta B plots from
> Intermagnet.  I'm not sure how the 10nT anomaly would appear if the same
> Intermagnet processing algorithm was used.
> Hyomin ?????
>
> On 9/15/2020 10:38 AM, Phil Erickson 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
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> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>
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