<div dir="ltr">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!! <div><br></div><div><div><br></div><div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><table style="border-collapse:collapse;width:525px;border-spacing:0px;background-color:transparent;color:rgb(35,38,54);font-family:Poppins,sans-serif;font-size:16px"><tbody style="border:0px;padding:0px;font-size:0.9em"><tr><td style="padding:5px;font-size:0.9em;font-stretch:normal;line-height:1.5;color:rgb(255,0,0);border-width:0px 3px 0px 0px;border-bottom-style:initial;border-bottom-color:initial;border-top-style:initial;border-right-style:solid;border-left-style:initial;border-top-color:initial;border-right-color:rgb(204,0,0);border-left-color:initial;width:180px;vertical-align:middle"><a href="https://www.njit.edu/" style="background-color:transparent;color:rgb(51,122,183)" target="_blank"><img src="https://assets.njit.edu/uicomponents/NJIT-email-logo.png" alt="NJIT logo" style="border:0px;display:block;vertical-align:middle;width:150px;height:auto;max-width:150px"></a></td><td style="padding:5px 5px 5px 10px;font-size:12px;font-stretch:normal;line-height:16px;border:0px;font-family:Arial,Helvetica,sans-serif"><strong style="color:rgb(111,111,111);font-size:13px">Hyomin Kim</strong><br><font color="#6f6f6f">Assistant Professor</font><br><font color="#6f6f6f">Physics<br></font><font color="#666666">Center for Solar-Terrestrial Research<br>Institute for Space Weather Sciences</font><br><font color="#666666"><a href="mailto:hmkim@njit.edu" target="_blank">hmkim@njit.edu</a> • <span style="white-space:nowrap">(973) 596-5704</span><br><a href="https://web.njit.edu/~hmkim/" target="_blank">https://web.njit.edu/~hmkim/</a><br>104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102<br></font></td></tr></tbody></table></div></div></div></div></div></div></div></div></div><br></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 15, 2020 at 11:34 AM Phil Erickson <<a href="mailto:phil.erickson@gmail.com">phil.erickson@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Hyomin,<div><br></div><div> 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?</div><div><br></div><div>73</div><div>Phil</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 15, 2020 at 11:27 AM Kim, Hyomin <<a href="mailto:hmkim@njit.edu" target="_blank">hmkim@njit.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">Hi Phil,<div>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? </div><div><br></div><div>Hyomin</div><div><br clear="all"><div><div dir="ltr"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><table style="border-collapse:collapse;width:525px;border-spacing:0px;background-color:transparent;color:rgb(35,38,54);font-family:Poppins,sans-serif;font-size:16px"><tbody style="border:0px;padding:0px;font-size:0.9em"><tr><td style="padding:5px;font-size:0.9em;font-stretch:normal;line-height:1.5;color:rgb(255,0,0);border-width:0px 3px 0px 0px;border-right-style:solid;border-right-color:rgb(204,0,0);width:180px;vertical-align:middle"><a href="https://www.njit.edu/" style="background-color:transparent;color:rgb(51,122,183)" target="_blank"><img src="https://assets.njit.edu/uicomponents/NJIT-email-logo.png" alt="NJIT logo" style="border: 0px; display: block; vertical-align: middle; width: 150px; height: auto; max-width: 150px;"></a></td><td style="padding:5px 5px 5px 10px;font-size:12px;font-stretch:normal;line-height:16px;border:0px;font-family:Arial,Helvetica,sans-serif"><strong style="color:rgb(111,111,111);font-size:13px">Hyomin Kim</strong><br><font color="#6f6f6f">Assistant Professor</font><br><font color="#6f6f6f">Physics<br></font><font color="#666666">Center for Solar-Terrestrial Research<br>Institute for Space Weather Sciences</font><br><font color="#666666"><a href="mailto:hmkim@njit.edu" target="_blank">hmkim@njit.edu</a> • <span style="white-space:nowrap">(973) 596-5704</span><br><a href="https://web.njit.edu/~hmkim/" target="_blank">https://web.njit.edu/~hmkim/</a><br>104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102<br></font></td></tr></tbody></table></div></div></div></div></div></div></div></div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 15, 2020 at 10:39 AM Phil Erickson via TangerineSDR <<a href="mailto:tangerinesdr@lists.tapr.org" target="_blank">tangerinesdr@lists.tapr.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><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" target="_blank">wittend@wwrinc.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><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">phil.erickson@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><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">tangerinesdr@lists.tapr.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid 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">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">hmkim@njit.edu</a>>, David Witten <<a href="mailto:wittend@wwrinc.com" target="_blank">wittend@wwrinc.com</a>>, Dr. Nathaniel A. Frissell Ph.D. <<a href="mailto:nathaniel.frissell@scranton.edu" target="_blank">nathaniel.frissell@scranton.edu</a>>, Dave Larsen <<a href="mailto:kv0s.dave@gmail.com" target="_blank">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>
</div></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr">----<br>Phil Erickson<br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a><br></div>
</blockquote></div>
</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr">----<br>Phil Erickson<br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a><br></div>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr">----<br>Phil Erickson<br><a href="mailto:phil.erickson@gmail.com" target="_blank">phil.erickson@gmail.com</a><br></div>
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