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<font face="Arial">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.<br>
Hyomin ?????<br>
</font><br>
<div class="moz-cite-prefix">On 9/15/2020 10:38 AM, Phil Erickson
wrote:<br>
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<blockquote type="cite"
cite="mid:CAAZaqEucQABc3SZys+6gootY3YLJiNQqnURHYHoUU+Yk7WbMyg@mail.gmail.com">
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<div dir="ltr">Hi Dave,
<div><br>
</div>
<div> 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.</div>
<div><br>
</div>
<div>73<br>
</div>
<div>Phil W1PJE</div>
<div><br>
</div>
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Tue, Sep 15, 2020 at 10:34
AM David Witten <<a href="mailto:wittend@wwrinc.com"
moz-do-not-send="true">wittend@wwrinc.com</a>> wrote:<br>
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<div dir="ltr">@Phil,
<div><br>
</div>
<div>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)<br>
</div>
<div><br>
</div>
<div>Dave Witten, KD0EAG</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Tue, Sep 15, 2020 at
7:21 AM Phil Erickson <<a
href="mailto:phil.erickson@gmail.com" target="_blank"
moz-do-not-send="true">phil.erickson@gmail.com</a>>
wrote:<br>
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<div dir="ltr">Hi all,<br>
<div><br>
</div>
<div> 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?</div>
<div><br>
</div>
<div>73</div>
<div>Phil W1PJE</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Sep 14, 2020
at 10:49 PM David Witten via TangerineSDR <<a
href="mailto:tangerinesdr@lists.tapr.org"
target="_blank" moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px
0px
0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">
<div dir="ltr">I don't believe that my previous post
carried the file K2KGJ provided.<br>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">----------
Forwarded message ---------<br>
From: <strong class="gmail_sendername"
dir="auto">Julius Madey</strong> <span
dir="auto"><<a
href="mailto:hillfox@fairpoint.net"
target="_blank" moz-do-not-send="true">hillfox@fairpoint.net</a>></span><br>
Date: Mon, Sep 14, 2020 at 4:26 PM<br>
Subject: another 24hour RM3100 run and
comparison with Fredericksburg<br>
To: Kim, Hyomin <<a
href="mailto:hmkim@njit.edu" target="_blank"
moz-do-not-send="true">hmkim@njit.edu</a>>,
David Witten <<a
href="mailto:wittend@wwrinc.com"
target="_blank" moz-do-not-send="true">wittend@wwrinc.com</a>>,
Dr. Nathaniel A. Frissell Ph.D. <<a
href="mailto:nathaniel.frissell@scranton.edu"
target="_blank" moz-do-not-send="true">nathaniel.frissell@scranton.edu</a>>,
Dave Larsen <<a
href="mailto:kv0s.dave@gmail.com"
target="_blank" moz-do-not-send="true">kv0s.dave@gmail.com</a>><br>
</div>
<br>
<br>
<div> <font face="Arial">All, <br>
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. <br>
<br>
The vertical axes scales on all plots are as
close as I could match them by eye in cutting
and pasting.<br>
<br>
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.<br>
<br>
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. <br>
<br>
Jules - K2KGJ<br>
</font> </div>
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</blockquote>
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<div><br>
</div>
-- <br>
<div dir="ltr">----<br>
Phil Erickson<br>
<a href="mailto:phil.erickson@gmail.com" target="_blank"
moz-do-not-send="true">phil.erickson@gmail.com</a><br>
</div>
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</blockquote>
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<br clear="all">
<div><br>
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-- <br>
<div dir="ltr" class="gmail_signature">----<br>
Phil Erickson<br>
<a href="mailto:phil.erickson@gmail.com" target="_blank"
moz-do-not-send="true">phil.erickson@gmail.com</a><br>
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