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    <font face="Arial">Hyomin,<br>
      Since our last, I've had to devote time to several other matters
      and haven't progressed much toward your unit.  However, that
      appears to be a good thing since I was planning to send you the
      single mag unit I've been using here repackaged for burial up to
      30 inches and with cable connections that match your present
      setup. Along with that, I was building a two magnetometer unit to
      do comparisons in my location.<br>
      <br>
      So, I'll reverse course and finish the two mag unit for you.  The
      magnetometer adapter boards will be the same as you're using now
      the only change being the second magnetometer and the termperature
      sensor will have different addresses on the i2c bus .... you
      access both mags on the same cable.  Dave Witten will have to do
      some program changes to capture both units but the setup will
      provide the best arrangement for comparison of two magnetometers
      ...... both in the same local temperature and magnetic
      environment.<br>
      <br>
      Jules<br>
      <br>
    </font><br>
    <div class="moz-cite-prefix">On 10/29/2020 1:15 PM, Kim, Hyomin
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAFXoXAWaJ1_6nKgH4oF1=699RtcLaC2ZU_bEw44SZMb7Kq-oLQ@mail.gmail.com">
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      <div dir="ltr">Hi Jules,
        <div>Could you please briefly give us an update on how things
          go?</div>
        <div>I'd like to have at least two sensors so signals can be
          compared back to back. </div>
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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"
                                        moz-do-not-send="true">hmkim@njit.edu</a> • <span
                                        style="white-space:nowrap">(973) 596-5704</span><br>
                                      <a
                                        href="https://web.njit.edu/~hmkim/"
                                        target="_blank"
                                        moz-do-not-send="true">https://web.njit.edu/~hmkim/</a><br>
                                      104 Tiernan Hall, 161 Warren
                                      Street, Newark, NJ 07102<br>
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      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">On Tue, Oct 13, 2020 at 11:33
          PM Kim, Hyomin <<a href="mailto:hmkim@njit.edu"
            moz-do-not-send="true">hmkim@njit.edu</a>> wrote:<br>
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          <div dir="ltr">Sounds good. Looking forward to it!
            <div>We also have to coordinate with Gil or Chris (another
              NJIT engineer) who will escort us there. </div>
            <div><br>
            </div>
            <div>Hyomin</div>
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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"
                                            moz-do-not-send="true">hmkim@njit.edu</a> • <span
                                            style="white-space:nowrap">(973) 596-5704</span><br>
                                          <a
                                            href="https://web.njit.edu/~hmkim/"
                                            target="_blank"
                                            moz-do-not-send="true">https://web.njit.edu/~hmkim/</a><br>
                                          104 Tiernan Hall, 161 Warren
                                          Street, Newark, NJ 07102<br>
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          <div class="gmail_quote">
            <div dir="ltr" class="gmail_attr">On Tue, Oct 13, 2020 at
              8:40 PM Julius Madey <<a
                href="mailto:hillfox@fairpoint.net" target="_blank"
                moz-do-not-send="true">hillfox@fairpoint.net</a>>
              wrote:<br>
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              <div> <font face="Arial">I think that would work.   Have
                  to finish some assembly here and then come up with a
                  schedule.<br>
                  Jules<br>
                </font><br>
                <div>On 10/13/2020 5:13 PM, Dr. Nathaniel A. Frissell
                  Ph.D. wrote:<br>
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                    <p class="MsoNormal">Hi Hyomin and Jules,</p>
                    <p class="MsoNormal"> </p>
                    <p class="MsoNormal">If I’m available, I’d like to
                      join you as well. I’d really enjoy getting to meet
                      Jules in person.</p>
                    <p class="MsoNormal"> </p>
                    <p class="MsoNormal">73 de Nathaniel</p>
                    <p class="MsoNormal"> </p>
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                      <p class="MsoNormal"><b>From:</b> Kim, Hyomin <a
                          href="mailto:hmkim@njit.edu" target="_blank"
                          moz-do-not-send="true"><hmkim@njit.edu></a>
                        <br>
                        <b>Sent:</b> Tuesday, October 13, 2020 5:02 PM<br>
                        <b>To:</b> Julius Madey <a
                          href="mailto:hillfox@fairpoint.net"
                          target="_blank" moz-do-not-send="true"><hillfox@fairpoint.net></a><br>
                        <b>Cc:</b> TAPR TangerineSDR Modular Software
                        Defined Radio <a
                          href="mailto:tangerinesdr@lists.tapr.org"
                          target="_blank" moz-do-not-send="true"><tangerinesdr@lists.tapr.org></a>;
                        John Gibbons <a href="mailto:jcg66@case.edu"
                          target="_blank" moz-do-not-send="true"><jcg66@case.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><br>
                        <b>Subject:</b> Re: [TangerineSDR] Fwd: another
                        24hour RM3100 run and comparison with
                        Fredericksburg</p>
                    </div>
                    <p class="MsoNormal"> </p>
                    <div>
                      <p class="MsoNormal">Hi Jules - Thanks for your
                        tip. Would you be willing to come down here to
                        install it together? It would be fun!</p>
                      <div>
                        <p class="MsoNormal"> </p>
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                      <div>
                        <p class="MsoNormal">All - It appears that the
                          magnetometer I have is behaving well. However,
                          it would be better if I have about >2 sets
                          so I can check whether all the sensors are
                          consistently behaving (which is extremely
                          important for such a largely spaced network
                          configuration). Do we have a timeline for more
                          testing sets? If not, I will visit Jenny Jump
                          to install the sensor again with a better
                          temperature management scheme as Jules
                          suggested. </p>
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                      <div>
                        <p class="MsoNormal"> </p>
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                      <div>
                        <p class="MsoNormal">Sorry for my slow response.
                          I am quite swamped by my teaching workload
                          this semester (somewhat unexpected...). </p>
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                        <p class="MsoNormal">Cheers,</p>
                      </div>
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                        <p class="MsoNormal">Hyomin</p>
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                                                  <p class="MsoNormal"
                                                    style="line-height:12pt"><strong><span
style="font-size:10pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Hyomin
                                                        Kim</span></strong><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                    </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Assistant
                                                      Professor</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                    </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Physics<br>
                                                    </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(102,102,102)">Center
                                                      for
                                                      Solar-Terrestrial
                                                      Research<br>
                                                      Institute for
                                                      Space Weather
                                                      Sciences</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                    </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(102,102,102)"><a
href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true">hmkim@njit.edu</a> • (973) 596-5704<br>
                                                      <a
                                                        href="https://web.njit.edu/~hmkim/"
                                                        target="_blank"
moz-do-not-send="true">https://web.njit.edu/~hmkim/</a><br>
                                                      104 Tiernan Hall,
                                                      161 Warren Street,
                                                      Newark, NJ 07102</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"></span></p>
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                        <p class="MsoNormal">On Mon, Oct 5, 2020 at 6:07
                          PM Julius Madey <<a
                            href="mailto:hillfox@fairpoint.net"
                            target="_blank" moz-do-not-send="true">hillfox@fairpoint.net</a>>
                          wrote:</p>
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                          <p class="MsoNormal"
                            style="margin-bottom:12pt"><span
                              style="font-family:Arial,sans-serif">Hyomin,<br>
                              During your run, the temperature of the
                              3100 was probably reasonably constant so
                              your result is consistent with basic 3100
                              specs.  Keeping the temperature constant
                              over 24 hours should give you a close
                              alignment with future JJ station
                              measurements.   Good news.  <br>
                              I can house your rm3100 in the same way I
                              did mine or, I think I have enough extra
                              parts now from Dave to make one up and
                              send it down .... possibly drive it down
                              since you're about 150 road miles from
                              here, which I can do in three hours.<br>
                              Jules<br>
                              <br>
                            </span></p>
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                            <p class="MsoNormal">On 10/5/2020 5:31 PM,
                              Kim, Hyomin wrote:</p>
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                                <p class="MsoNormal">Hi Dave, Jules and
                                  Nathaniel,</p>
                              </div>
                              <div>
                                <p class="MsoNormal">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. </p>
                              </div>
                              <div>
                                <p class="MsoNormal"> </p>
                              </div>
                              <div>
                                <p class="MsoNormal">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...</p>
                              </div>
                              <div>
                                <p class="MsoNormal"> </p>
                              </div>
                              <div>
                                <p class="MsoNormal">Hyomin</p>
                              </div>
                              <div>
                                <p class="MsoNormal"> </p>
                              </div>
                              <div>
                                <p class="MsoNormal"> </p>
                              </div>
                              <p class="MsoNormal"><br clear="all">
                              </p>
                              <div>
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                                                  style="width:393.75pt;border-collapse:collapse;border-spacing:0px"
                                                  width="525"
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style="width:135pt;border-top:initial;border-bottom:initial;border-left:initial;border-right:2.25pt
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                                                        width="180">
                                                        <p
                                                          class="MsoNormal"><a
href="https://www.njit.edu/" target="_blank" moz-do-not-send="true"><span
style="font-size:10pt;font-family:Arial,sans-serif;color:rgb(51,122,183);text-decoration:none"><img
                                                          style="width:
                                                          1.5625in;
                                                          height:
                                                          0.625in;"
                                                          id="gmail-m_-1811418376678649281gmail-m_8997182635278090925_x0000_i1025"
src="https://assets.njit.edu/uicomponents/NJIT-email-logo.png" alt="NJIT
                                                          logo"
                                                          moz-do-not-send="true"
                                                          width="150"
                                                          height="60"
                                                          border="0"></span></a><span
style="font-size:10pt;font-family:Arial,sans-serif;color:red"></span></p>
                                                      </td>
                                                      <td
                                                        style="padding:3.75pt
                                                        3.75pt 3.75pt
                                                        7.5pt;font-stretch:normal">
                                                        <p
                                                          class="MsoNormal"
style="line-height:12pt"><strong><span
style="font-size:10pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Hyomin
                                                          Kim</span></strong><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                          </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Assistant
                                                          Professor</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                          </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(111,111,111)">Physics<br>
                                                          </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(102,102,102)">Center
                                                          for
                                                          Solar-Terrestrial
                                                          Research<br>
                                                          Institute for
                                                          Space Weather
                                                          Sciences</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"><br>
                                                          </span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(102,102,102)"><a
href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true">hmkim@njit.edu</a> • (973) 596-5704<br>
                                                          <a
                                                          href="https://web.njit.edu/~hmkim/"
target="_blank" moz-do-not-send="true">https://web.njit.edu/~hmkim/</a><br>
                                                          104 Tiernan
                                                          Hall, 161
                                                          Warren Street,
                                                          Newark, NJ
                                                          07102</span><span
style="font-size:9pt;font-family:Arial,sans-serif;color:rgb(35,38,54)"></span></p>
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                                              </div>
                                            </div>
                                          </div>
                                        </div>
                                      </div>
                                    </div>
                                  </div>
                                </div>
                              </div>
                              <p class="MsoNormal"> </p>
                            </div>
                            <p class="MsoNormal"> </p>
                            <div>
                              <div>
                                <p class="MsoNormal">On Tue, Sep 22,
                                  2020 at 9:45 PM Julius Madey via
                                  TangerineSDR <<a
                                    href="mailto:tangerinesdr@lists.tapr.org"
                                    target="_blank"
                                    moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>>
                                  wrote:</p>
                              </div>
                              <blockquote
style="border-top:none;border-right:none;border-bottom:none;border-left:1pt
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                                <div>
                                  <p class="MsoNormal"
                                    style="margin-bottom:12pt"><span
                                      style="font-family:Arial,sans-serif">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>
                                    </span></p>
                                  <div>
                                    <p class="MsoNormal">On 9/22/2020
                                      7:52 PM, John Gibbons wrote:</p>
                                  </div>
                                  <blockquote
                                    style="margin-top:5pt;margin-bottom:5pt">
                                    <div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black">All,</span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black"> </span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black">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).</span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black"> </span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black">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.</span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black"> </span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black">You've
                                            probably already done this
                                            (if so please point me to
                                            it) but has this been looked
                                            at / tested for /
                                            quantified?</span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black"> </span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black">John
                                            N8OBJ</span></p>
                                      </div>
                                      <div>
                                        <p class="MsoNormal"><span
                                            style="font-size:12pt;font-family:Arial,sans-serif;color:black"> </span></p>
                                      </div>
                                      <div>
                                        <div>
                                          <div>
                                            <div>
                                              <div>
                                                <div>
                                                  <div>
                                                    <div>
                                                      <div>
                                                        <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
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                                                          <div>
                                                          <div>
                                                          <div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal">John
                                                          C. Gibbons</p>
                                                          </div>
                                                          <p
                                                          class="MsoNormal">Director
                                                          - Sears
                                                          Undergraduate
                                                          Design
                                                          Laboratory</p>
                                                          </div>
                                                          <p
                                                          class="MsoNormal">Dept.
                                                          of Electrical
                                                          Engineering
                                                          and Computer
                                                          Science</p>
                                                          </div>
                                                          </div>
                                                          <p
                                                          class="MsoNormal">Case
                                                          Western
                                                          Reserve
                                                          University  </p>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal">10900
                                                          Euclid Ave, <span
style="font-size:9.5pt">Glennan 314</span></p>
                                                          </div>
                                                          </div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"
style="margin-bottom:12pt"><span
                                                          style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:black">Cleveland,
                                                          Ohio
                                                           44106-7071<br>
                                                          Phone </span><a
href="tel:216-368-2816" target="_blank" moz-do-not-send="true"><span
style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:rgb(17,85,204)">(216)
                                                          368-2816</span></a><span
style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:black"> FAX </span><a
href="tel:216-368-6888" target="_blank" moz-do-not-send="true"><span
style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:rgb(17,85,204)">(216)
                                                          368-6888</span></a><span
style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:black"><br>
                                                          E-mail: </span><a
href="mailto:jcg66@case.edu" target="_blank" moz-do-not-send="true"><span
style="font-size:9.5pt;font-family:Helvetica,sans-serif;color:rgb(17,85,204)">jcg66@case.edu</span></a></p>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                          </div>
                                                        </div>
                                                      </div>
                                                    </div>
                                                  </div>
                                                </div>
                                              </div>
                                            </div>
                                          </div>
                                        </div>
                                      </div>
                                      <p class="MsoNormal"> </p>
                                    </div>
                                    <p class="MsoNormal"> </p>
                                    <div>
                                      <div>
                                        <p class="MsoNormal">On Mon, Sep
                                          21, 2020 at 4:18 PM Julius
                                          Madey via TangerineSDR <<a
href="mailto:tangerinesdr@lists.tapr.org" target="_blank"
                                            moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>>
                                          wrote:</p>
                                      </div>
                                      <blockquote
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                                        <div>
                                          <p class="MsoNormal"
                                            style="margin-bottom:12pt"><span
style="font-family:Arial,sans-serif">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 ?????</span></p>
                                          <div>
                                            <p class="MsoNormal">On
                                              9/15/2020 10:38 AM, Phil
                                              Erickson wrote:</p>
                                          </div>
                                          <blockquote
                                            style="margin-top:5pt;margin-bottom:5pt">
                                            <div>
                                              <p class="MsoNormal">Hi
                                                Dave, </p>
                                              <div>
                                                <p class="MsoNormal"> </p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal"> 
                                                  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.</p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal"> </p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal">73</p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal">Phil
                                                  W1PJE</p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal"> </p>
                                              </div>
                                              <div>
                                                <p class="MsoNormal"> </p>
                                              </div>
                                            </div>
                                            <p class="MsoNormal"> </p>
                                            <div>
                                              <div>
                                                <p class="MsoNormal">On
                                                  Tue, Sep 15, 2020 at
                                                  10:34 AM David Witten
                                                  <<a
                                                    href="mailto:wittend@wwrinc.com"
                                                    target="_blank"
                                                    moz-do-not-send="true">wittend@wwrinc.com</a>>
                                                  wrote:</p>
                                              </div>
                                              <blockquote
style="border-top:none;border-right:none;border-bottom:none;border-left:1pt
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                                                <div>
                                                  <p class="MsoNormal">@Phil,
                                                  </p>
                                                  <div>
                                                    <p class="MsoNormal"> </p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">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)</p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal"> </p>
                                                  </div>
                                                  <div>
                                                    <p class="MsoNormal">Dave
                                                      Witten, KD0EAG</p>
                                                  </div>
                                                </div>
                                                <p class="MsoNormal"> </p>
                                                <div>
                                                  <div>
                                                    <p class="MsoNormal">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:</p>
                                                  </div>
                                                  <blockquote
style="border-top:none;border-right:none;border-bottom:none;border-left:1pt
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                                                      <p
                                                        class="MsoNormal">Hi
                                                        all,</p>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"> </p>
                                                      </div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"> 
                                                          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?</p>
                                                      </div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal"> </p>
                                                      </div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal">73</p>
                                                      </div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal">Phil
                                                          W1PJE</p>
                                                      </div>
                                                    </div>
                                                    <p class="MsoNormal"> </p>
                                                    <div>
                                                      <div>
                                                        <p
                                                          class="MsoNormal">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:</p>
                                                      </div>
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                                                          <p
                                                          class="MsoNormal"
style="margin-bottom:12pt">I don't believe that my previous post carried
                                                          the file K2KGJ
                                                          provided.</p>
                                                          <div>
                                                          <div>
                                                          <p
                                                          class="MsoNormal">----------
                                                          Forwarded
                                                          message
                                                          ---------<br>
                                                          From: <strong><span
style="font-family:Calibri,sans-serif">Julius Madey</span></strong> <<a
href="mailto:hillfox@fairpoint.net" target="_blank"
                                                          moz-do-not-send="true">hillfox@fairpoint.net</a>><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>></p>
                                                          </div>
                                                          <p
                                                          class="MsoNormal"
style="margin-bottom:12pt"> </p>
                                                          <div>
                                                          <p
                                                          class="MsoNormal"><span
style="font-family:Arial,sans-serif">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</span></p>
                                                          </div>
                                                          </div>
                                                        </div>
                                                        <p
                                                          class="MsoNormal">--
                                                          <br>
                                                          TangerineSDR
                                                          mailing list<br>
                                                          <a
                                                          href="mailto:TangerineSDR@lists.tapr.org"
target="_blank" moz-do-not-send="true">TangerineSDR@lists.tapr.org</a><br>
                                                          <a
href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org"
target="_blank" moz-do-not-send="true">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a></p>
                                                      </blockquote>
                                                    </div>
                                                    <p class="MsoNormal"><br
                                                        clear="all">
                                                    </p>
                                                    <div>
                                                      <p
                                                        class="MsoNormal"> </p>
                                                    </div>
                                                    <p class="MsoNormal">--
                                                    </p>
                                                    <div>
                                                      <p
                                                        class="MsoNormal">----<br>
                                                        Phil Erickson<br>
                                                        <a
                                                          href="mailto:phil.erickson@gmail.com"
target="_blank" moz-do-not-send="true">phil.erickson@gmail.com</a></p>
                                                    </div>
                                                  </blockquote>
                                                </div>
                                              </blockquote>
                                            </div>
                                            <p class="MsoNormal"><br
                                                clear="all">
                                            </p>
                                            <div>
                                              <p class="MsoNormal"> </p>
                                            </div>
                                            <p class="MsoNormal">-- </p>
                                            <div>
                                              <p class="MsoNormal">----<br>
                                                Phil Erickson<br>
                                                <a
                                                  href="mailto:phil.erickson@gmail.com"
                                                  target="_blank"
                                                  moz-do-not-send="true">phil.erickson@gmail.com</a></p>
                                            </div>
                                          </blockquote>
                                          <p class="MsoNormal"> </p>
                                        </div>
                                        <p class="MsoNormal">-- <br>
                                          TangerineSDR mailing list<br>
                                          <a
                                            href="mailto:TangerineSDR@lists.tapr.org"
                                            target="_blank"
                                            moz-do-not-send="true">TangerineSDR@lists.tapr.org</a><br>
                                          <a
href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org"
                                            target="_blank"
                                            moz-do-not-send="true">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a></p>
                                      </blockquote>
                                    </div>
                                  </blockquote>
                                  <p class="MsoNormal"> </p>
                                </div>
                                <p class="MsoNormal">-- <br>
                                  TangerineSDR mailing list<br>
                                  <a
                                    href="mailto:TangerineSDR@lists.tapr.org"
                                    target="_blank"
                                    moz-do-not-send="true">TangerineSDR@lists.tapr.org</a><br>
                                  <a
href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org"
                                    target="_blank"
                                    moz-do-not-send="true">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a></p>
                              </blockquote>
                            </div>
                          </blockquote>
                          <p class="MsoNormal"> </p>
                        </div>
                      </blockquote>
                    </div>
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                <br>
              </div>
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