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    <font face="Arial">Great !   Out of direct sunlight and close to

      ground level would be best.</font><br>

    <br>

    <div class="moz-cite-prefix">On 8/3/2020 11:28 AM, Kim, Hyomin

      wrote:<br>

    </div>

    <blockquote type="cite"

cite="mid:CAFXoXAXgscUup7mE-sAUiuLnpi0oXOZCNWxXJppRScaPX6QDMw@mail.gmail.com">

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      <div dir="ltr">This time, I will try to place the sensor as close

        as possible to the science magnetometer at Jenny Jump and

        insulate it to minimize the temperature effect if any. 

        <div>Gil (the site manager) and I will not be available until

          next week but will try to address this issue as soon as

          possible. </div>

        <div><br>

        </div>

        <div>Hyomin</div>

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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/"

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                                      target="_blank"

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style="border:0px;display:block;vertical-align:middle;width:150px;height:auto;max-width:150px"

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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"

                                        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 Sun, Aug 2, 2020 at 1:49 PM

          Julius Madey via TangerineSDR <<a

            href="mailto:tangerinesdr@lists.tapr.org"

            moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>>

          wrote:<br>

        </div>

        <blockquote class="gmail_quote" style="margin:0px 0px 0px

          0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">

          <div> <font face="Arial">That is the claim.  So either that's

              not the case, or perhaps it holds for levels in excess of

              a few hundred nT or something else is causing the

              variations that were observed at Jenny Jump and in my

              various tests.  It is probably not B fields very local to

              the adapter board, which sees currents in the 10mA range. 

              Just did some tests with 100mA into a twisted pair of #31

              magnet wire held near different parts of the RM3100 board.<br>

              <br>

              If the twisted pair was 0.5cm or more away from anything

              on the board, no effect observed.  If it lay directly on

              one of the sensing inductors, effect was ~ 50nT.<br>

              <br>

              Another thought on temperature stability .... place the

              mag in an in-ground vault.  Back in the 60's when we

              needed xtal oscillator stability on the cheap and better

              than the usual xtal oven of the day, we put the oscillator

              assembly about 3 feet underground.  Very stable short term

              and excellent long term.  It would certainly work for 24

              hour observation periods.<br>

              <br>

              Jules Madey-K2KGJ<br>

            </font><br>

            <div>On 7/31/2020 1:38 PM, <a

                href="mailto:tangerinesdr-request@lists.tapr.org"

                target="_blank" moz-do-not-send="true">tangerinesdr-request@lists.tapr.org</a>

              wrote:<br>

            </div>

            <blockquote type="cite">

              <pre>Send TangerineSDR mailing list submissions to

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Today's Topics:

   1. Re: Mag update? (David G. McGaw)

   2. Re: Mag update? (David G. McGaw)

----------------------------------------------------------------------

Message: 1

Date: Fri, 31 Jul 2020 13:36:38 -0400

From: "David G. McGaw" <a href="mailto:david.g.mcgaw@dartmouth.edu" target="_blank" moz-do-not-send="true"><david.g.mcgaw@dartmouth.edu></a>

To: <a href="mailto:tangerinesdr@lists.tapr.org" target="_blank" moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>

Subject: Re: [TangerineSDR] Mag update?

Message-ID: <a href="mailto:3718db2a-97b4-eba5-8f0a-e94ead711cd7@dartmouth.edu" target="_blank" moz-do-not-send="true"><3718db2a-97b4-eba5-8f0a-e94ead711cd7@dartmouth.edu></a>

Content-Type: text/plain; charset="utf-8"; Format="flowed"

Interesting, this, as it says on the RM3100 webpage "Measurements are 

stable over temperature and inherently free of offset drift" and a 

temperature coefficient is not even mentioned in the specs.

David N1HAC

On 7/31/20 11:18 AM, Julius Madey via TangerineSDR wrote:

</pre>

              <blockquote type="cite">

                <pre>Good morning all.? Betty Zhang at PNI is responding to the request and 

has asked for more information which I have supplied, including some 

of the JJ test comparisons, how I ran the calibration runs I did, data 

reduction, etc.

I would suggest one further item for consideration in getting to a 

useable solution.? If RM3100 temperature turns out to be a concern, 

place the sensor in a small foam insulated box with a proportionally 

controlled heater which maintains the temperature at something just 

above what would be considered the highest environmental temperature 

around the sensor.? That should be relatively simple to do without 

introducing an interfering magnetic field local to the sensor.? Some 

power would be required but with careful design, I would think well 

within 1 watt.

Another possibility would be using peltier effect heat pumps to do the 

same thing, although the technology would probably result is stronger 

local B fields from the peltier device and require more power.? The 

insulated foam box and proportional heater is also probably the 

cheapest approach considering the need to keep overall costs for the 

expected users low.

Regards,

Jules

On 7/31/2020 10:26 AM, David Witten wrote:

</pre>

                <blockquote type="cite">

                  <pre>Hyomin,

I'm not certain what the next step should be.? Julius is hoping for 

further response from PNI on this subject.

If temperature compensation does account for the differences in 

observed response I would think that the important thing to? do may 

be to find a way to calibrate out the discrepancy.? Then we can look 

at insulation to further minimize the effect.

Calibration will hopefully give us more meaningful values to begin?with.

Insulation will dampen the effect of those behaviors over short 

timespans.

Fortunately, neither requires changes?in the basic circuit, just 

adjustments to the data collection and device packaging.

Dave

On Fri, Jul 31, 2020 at 9:10 AM Kim, Hyomin <<a href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true">hmkim@njit.edu</a> 

<a href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true"><mailto:hmkim@njit.edu></a>> wrote:

    Hi Dave

    Sorry that I've been out of the loop for a while as I was

    completely caught up with something else. May I ask you what the

    current status is?

    I can visit Jenny Jump if there is something that I can do. At

    this moment, I cannot think of anything that can be fixed from my

    end.

    If the temperature compensation is the issue, I could install

    insulations around the sensor.

    Hyomin

    NJIT logo

    <a href="https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.njit.edu%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C2e59f624469544810c1c08d8356521e1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318055785489421&sdata=TmqWJw6VYdRSrTgS2xSIifG4OTUj6z5lcBLqd2UedyY%3D&reserved=0" target="_blank" moz-do-not-send="true"><https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.njit.edu%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C2e59f624469544810c1c08d8356521e1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318055785489421&sdata=TmqWJw6VYdRSrTgS2xSIifG4OTUj6z5lcBLqd2UedyY%3D&reserved=0></a>

        *Hyomin Kim*

    Assistant Professor

    Physics

    Center for Solar-Terrestrial Research

    Institute for Space Weather Sciences

    <a href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true">hmkim@njit.edu</a> <a href="mailto:hmkim@njit.edu" target="_blank" moz-do-not-send="true"><mailto:hmkim@njit.edu></a>?? (973)?596-5704

    <a href="https://web.njit.edu/~hmkim/" target="_blank" moz-do-not-send="true">https://web.njit.edu/~hmkim/</a>

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    104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102

</pre>

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Message: 2

Date: Fri, 31 Jul 2020 13:37:51 -0400

From: "David G. McGaw" <a href="mailto:david.g.mcgaw@dartmouth.edu" target="_blank" moz-do-not-send="true"><david.g.mcgaw@dartmouth.edu></a>

To: <a href="mailto:tangerinesdr@lists.tapr.org" target="_blank" moz-do-not-send="true">tangerinesdr@lists.tapr.org</a>