[TangerineSDR] TangerineSDR Digest, Vol 16, Issue 32_RM3100temperature effects

Julius Madey hillfox at fairpoint.net
Mon Aug 3 11:57:16 EDT 2020


Great !   Out of direct sunlight and close to ground level would be best.

On 8/3/2020 11:28 AM, Kim, Hyomin wrote:
> 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.
> Gil (the site manager) and I will not be available until next week but 
> will try to address this issue as soon as possible.
>
> Hyomin
>
> NJIT logo <https://www.njit.edu/> 	*Hyomin Kim*
> Assistant Professor
> Physics
> Center for Solar-Terrestrial Research
> Institute for Space Weather Sciences
> hmkim at njit.edu <mailto:hmkim at njit.edu> • (973) 596-5704
> https://web.njit.edu/~hmkim/
> 104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>
>
>
> On Sun, Aug 2, 2020 at 1:49 PM Julius Madey via TangerineSDR 
> <tangerinesdr at lists.tapr.org <mailto:tangerinesdr at lists.tapr.org>> wrote:
>
>     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.
>
>     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.
>
>     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.
>
>     Jules Madey-K2KGJ
>
>     On 7/31/2020 1:38 PM, tangerinesdr-request at lists.tapr.org
>     <mailto:tangerinesdr-request at lists.tapr.org> wrote:
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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"<david.g.mcgaw at dartmouth.edu>  <mailto:david.g.mcgaw at dartmouth.edu>
>>     To:tangerinesdr at lists.tapr.org  <mailto:tangerinesdr at lists.tapr.org>
>>     Subject: Re: [TangerineSDR] Mag update?
>>     Message-ID:<3718db2a-97b4-eba5-8f0a-e94ead711cd7 at dartmouth.edu>  <mailto:3718db2a-97b4-eba5-8f0a-e94ead711cd7 at dartmouth.edu>
>>     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:
>>>     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:
>>>>     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 <hmkim at njit.edu  <mailto:hmkim at njit.edu>  
>>>>     <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>> 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
>>>>          <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>  <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>
>>>>          	*Hyomin Kim*
>>>>          Assistant Professor
>>>>          Physics
>>>>          Center for Solar-Terrestrial Research
>>>>          Institute for Space Weather Sciences
>>>>          hmkim at njit.edu  <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>?? (973)?596-5704
>>>>          https://web.njit.edu/~hmkim/
>>>>          <https://nam12.safelinks.protection.outlook.com/?url=https:%2F%2Fweb.njit.edu%2F~hmkim%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C2e59f624469544810c1c08d8356521e1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318055785499423&sdata=Nz%2B0y9A0svN6RegTKpvfpWgJ%2FCb1N1vKkFr71fqtDFg%3D&reserved=0>  <https://nam12.safelinks.protection.outlook.com/?url=https:%2F%2Fweb.njit.edu%2F~hmkim%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C2e59f624469544810c1c08d8356521e1%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318055785499423&sdata=Nz%2B0y9A0svN6RegTKpvfpWgJ%2FCb1N1vKkFr71fqtDFg%3D&reserved=0>
>>>>          104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>>>
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>>     ------------------------------
>>
>>     Message: 2
>>     Date: Fri, 31 Jul 2020 13:37:51 -0400
>>     From: "David G. McGaw"<david.g.mcgaw at dartmouth.edu>  <mailto:david.g.mcgaw at dartmouth.edu>
>>     To:tangerinesdr at lists.tapr.org  <mailto:tangerinesdr at lists.tapr.org>
>>     Subject: Re: [TangerineSDR] Mag update?
>>     Message-ID:<f86f2596-ef2b-25c7-5b12-3f83c4429cb3 at dartmouth.edu>  <mailto:f86f2596-ef2b-25c7-5b12-3f83c4429cb3 at dartmouth.edu>
>>     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 11:44 AM, Julius Madey via TangerineSDR wrote:
>>>     One more thought.? I've asked PNI for information both on temperature
>>>     and supply voltage sensitivity, the only two variables I could think
>>>     of besides the need to minimize local B fields due to currents in
>>>     circuit board traces, nearby wiring, etc.
>>>
>>>     I did not find data on the temperature stability of the 3.3 volt
>>>     regulator Dave's JJ board? is using but the regulator I used with the
>>>     original adapter board Dave sent me has about 5 millivolts of change
>>>     out of 3.3 volts between 25 and 50 C and Dave's is probably similar.?
>>>     That doesn't seem like enough change to produce the observed
>>>     variations but that information was given to PNI as well.
>>>
>>>
>>>     On 7/31/2020 10:26 AM, David Witten wrote:
>>>>     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 <hmkim at njit.edu  <mailto:hmkim at njit.edu>  
>>>>     <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>> 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
>>>>          <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.njit.edu%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C4a7b93ba3ecd455d4e0f08d83568b144%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318071068004568&sdata=O09d%2FBt6N3Iq%2FUVQ5KdQz6V0Km3YIN%2BucnCkc1JQC8E%3D&reserved=0>  <https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.njit.edu%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C4a7b93ba3ecd455d4e0f08d83568b144%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318071068004568&sdata=O09d%2FBt6N3Iq%2FUVQ5KdQz6V0Km3YIN%2BucnCkc1JQC8E%3D&reserved=0>
>>>>          	*Hyomin Kim*
>>>>          Assistant Professor
>>>>          Physics
>>>>          Center for Solar-Terrestrial Research
>>>>          Institute for Space Weather Sciences
>>>>          hmkim at njit.edu  <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>  <mailto:hmkim at njit.edu>?? (973)?596-5704
>>>>          https://web.njit.edu/~hmkim/
>>>>          <https://nam12.safelinks.protection.outlook.com/?url=https:%2F%2Fweb.njit.edu%2F~hmkim%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C4a7b93ba3ecd455d4e0f08d83568b144%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318071068004568&sdata=W4LqWL2HfX4hkY0cMhqWDsY%2FlWS9nz1bpjcEZ9%2FbSNE%3D&reserved=0>  <https://nam12.safelinks.protection.outlook.com/?url=https:%2F%2Fweb.njit.edu%2F~hmkim%2F&data=02%7C01%7CDavid.G.McGaw%40dartmouth.edu%7C4a7b93ba3ecd455d4e0f08d83568b144%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637318071068004568&sdata=W4LqWL2HfX4hkY0cMhqWDsY%2FlWS9nz1bpjcEZ9%2FbSNE%3D&reserved=0>
>>>>          104 Tiernan Hall, 161 Warren Street, Newark, NJ 07102
>>>>
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>>     ------------------------------
>>
>>     End of TangerineSDR Digest, Vol 16, Issue 32
>>     ********************************************
>>
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