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

[Phil Erickson]

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
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