<div dir="ltr"><div>Hi Dave, Jules and Nathaniel,</div><div>Sorry that it took me so long to work on the data that was retrieved from Jenny Jump. The two sensors (Bartington and our mag) were placed inside a solenoid which was then placed inside a mu-metal case. Long story short, there is NO reason to believe that our magnetometer behaves in a different way compared to the other. They trace the artificially generated fields well. The only thing that needs to be addressed later is that the given field was so big that the output signals were saturated - the fields inside the solenoids should have been decreased to avoid saturation. My oversight that I had to leave the site in a rush. However, both sensors traced the fields in the same way. I hope I will have more time to stay at Jenny Jump next time to monitor the signals more carefully as the NJIT system has now been fixed. </div><div><br></div><div>Please share this during the Tangerine meeting tonight as I will not be able to attend it this time due to the conflict with my lecture which is expected to be longer than last week...</div><div><br></div><div>Hyomin</div><div><br></div><div><br></div><br clear="all"><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><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Sep 22, 2020 at 9:45 PM Julius Madey via TangerineSDR <<a href="mailto:tangerinesdr@lists.tapr.org">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>
<font face="Arial">Dear John,<br>
Yes, temperature information was posted a while back. PNI
initially claimed that there was no temperature effect due to the
essentially self compensating scheme used for field measurement.
After I measured as much as a 7-10nT per degree C tempco in some
controlled oven experiments and sharing that data with PNI, PNI
eventually replied that engineering had measured a maximum of +/-
2nT per degree C for the inductors alone but had not characterized
the complete sensor.<br>
<br>
The data I have taken so far is not complete but indicates that
the tempco (1) may not be equal on all axes, including differences
in sign and (2) may not be assumed to be equal for any two units
and (3) may not be linear with temperature, making algorithmic
correction of the recorded data difficult.<br>
<br>
Hence, my attempts to achieve temperature stabilization to better
than 1 degree C over 24 hours for the recordings I've been doing
(sensor in a housing that can be easily buried sub surface).<br>
<br>
Have also done some experiments with an insulated chamber
containing a thermal mass, equivalent to a low pass filter, to
achieve stabilization. <br>
<br>
Another approach is a temperature controlled oven set to a few
degrees above expected maximum local ambient temp but that
requires power, which complicates long cable runs.<br>
<br>
At just 19-20 inches below grade in my shaded woodlot, 24 hour
temperature stability has been within 0.7C. Another 12-16 inches
for the next install should bring that to a diurnal variation of
perhaps 0.1C in this location.<br>
<br>
Jules K2KGJ<br>
<br>
<br>
</font><br>
<div>On 9/22/2020 7:52 PM, John Gibbons
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">All,</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">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).</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">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.</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">You've
probably already done this (if so please point me to it) but
has this been looked at / tested for / quantified?</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><br>
</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)">John
N8OBJ</div>
<div class="gmail_default" style="font-family:arial,helvetica,sans-serif;font-size:small;color:rgb(0,0,0)"><br>
</div>
<div>
<div dir="ltr">
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div>
<div dir="ltr">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>
<div>John C.
Gibbons<br>
</div>
Director -
Sears
Undergraduate
Design
Laboratory<br>
</div>
Dept. of
Electrical
Engineering and
Computer Science</div>
</div>
Case Western Reserve
University <br>
</div>
<div>10900 Euclid Ave,
<span style="font-size:12.8px">Glennan
314</span><span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px"><br>
</span></div>
</div>
<div><span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">Cleveland,
Ohio 44106-7071</span><br style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">
<span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">Phone </span><a href="tel:216-368-2816" value="+12163684572" style="color:rgb(17,85,204);font-family:Helvetica;font-size:12.8px" target="_blank">(216)
368-2816</a><span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px"> FAX </span><a href="tel:216-368-6888" value="+12163686888" style="color:rgb(17,85,204);font-family:Helvetica;font-size:12.8px" target="_blank">(216)
368-6888</a><br style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">
<span style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">E-mail:
</span><a href="mailto:jcg66@case.edu" style="color:rgb(17,85,204);font-family:Helvetica;font-size:12.8px" target="_blank">jcg66@case.edu</a><br style="color:rgb(0,0,0);font-family:Helvetica;font-size:12.8px">
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Sep 21, 2020 at 4:18
PM Julius Madey 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> <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>On 9/15/2020 10:38 AM, Phil Erickson wrote:<br>
</div>
<blockquote type="cite">
<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>
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