[TangerineSDR] Fwd: another 24hour RM3100 run and comparison with Fredericksburg

Julius Madey hillfox at fairpoint.net
Tue Oct 13 20:39:48 EDT 2020


I think that would work.   Have to finish some assembly here and then 
come up with a schedule.
Jules

On 10/13/2020 5:13 PM, Dr. Nathaniel A. Frissell Ph.D. wrote:
>
> Hi Hyomin and Jules,
>
> If I’m available, I’d like to join you as well. I’d really enjoy 
> getting to meet Jules in person.
>
> 73 de Nathaniel
>
> *From:* Kim, Hyomin <hmkim at njit.edu>
> *Sent:* Tuesday, October 13, 2020 5:02 PM
> *To:* Julius Madey <hillfox at fairpoint.net>
> *Cc:* TAPR TangerineSDR Modular Software Defined Radio 
> <tangerinesdr at lists.tapr.org>; John Gibbons <jcg66 at case.edu>; David 
> Witten <wittend at wwrinc.com>; Dr. Nathaniel A. Frissell Ph.D. 
> <nathaniel.frissell at scranton.edu>
> *Subject:* Re: [TangerineSDR] Fwd: another 24hour RM3100 run and 
> comparison with Fredericksburg
>
> Hi Jules - Thanks for your tip. Would you be willing to come down here 
> to install it together? It would be fun!
>
> 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.
>
> Sorry for my slow response. I am quite swamped by my teaching workload 
> this semester (somewhat unexpected...).
>
> Cheers,
>
> 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 Mon, Oct 5, 2020 at 6:07 PM Julius Madey <hillfox at fairpoint.net 
> <mailto:hillfox at fairpoint.net>> wrote:
>
>     Hyomin,
>     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.
>     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.
>     Jules
>
>     On 10/5/2020 5:31 PM, Kim, Hyomin wrote:
>
>         Hi Dave, Jules and Nathaniel,
>
>         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.
>
>         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...
>
>         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 Tue, Sep 22, 2020 at 9:45 PM Julius Madey via TangerineSDR
>         <tangerinesdr at lists.tapr.org
>         <mailto:tangerinesdr at lists.tapr.org>> wrote:
>
>             Dear John,
>             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.
>
>             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.
>
>             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).
>
>             Have also done some experiments with an insulated chamber
>             containing a thermal mass, equivalent to a low pass
>             filter, to achieve stabilization.
>
>             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.
>
>             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.
>
>             Jules K2KGJ
>
>
>             On 9/22/2020 7:52 PM, John Gibbons wrote:
>
>                 All,
>
>                 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).
>
>                 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.
>
>                 You've probably already done this (if so please point
>                 me to it) but has this been looked at / tested for /
>                 quantified?
>
>                 John N8OBJ
>
>                 John C. Gibbons
>
>                 Director - Sears Undergraduate Design Laboratory
>
>                 Dept. of Electrical Engineering and Computer Science
>
>                 Case Western Reserve University
>
>                 10900 Euclid Ave, Glennan 314
>
>                 Cleveland, Ohio  44106-7071
>                 Phone (216) 368-2816 <tel:216-368-2816> FAX (216)
>                 368-6888 <tel:216-368-6888>
>                 E-mail: jcg66 at case.edu <mailto:jcg66 at case.edu>
>
>                 On Mon, Sep 21, 2020 at 4:18 PM Julius Madey via
>                 TangerineSDR <tangerinesdr at lists.tapr.org
>                 <mailto:tangerinesdr at lists.tapr.org>> wrote:
>
>                     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.
>                     Hyomin ?????
>
>                     On 9/15/2020 10:38 AM, Phil Erickson wrote:
>
>                         Hi Dave,
>
>                           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.
>
>                         73
>
>                         Phil W1PJE
>
>                         On Tue, Sep 15, 2020 at 10:34 AM David Witten
>                         <wittend at wwrinc.com
>                         <mailto:wittend at wwrinc.com>> wrote:
>
>                             @Phil,
>
>                             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)
>
>                             Dave Witten, KD0EAG
>
>                             On Tue, Sep 15, 2020 at 7:21 AM Phil
>                             Erickson <phil.erickson at gmail.com
>                             <mailto:phil.erickson at gmail.com>> wrote:
>
>                                 Hi all,
>
>                                   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?
>
>                                 73
>
>                                 Phil W1PJE
>
>                                 On Mon, Sep 14, 2020 at 10:49 PM David
>                                 Witten via TangerineSDR
>                                 <tangerinesdr at lists.tapr.org
>                                 <mailto:tangerinesdr at lists.tapr.org>>
>                                 wrote:
>
>                                     I don't believe that my previous
>                                     post carried the file K2KGJ provided.
>
>                                     ---------- Forwarded message ---------
>                                     From: *Julius Madey*
>                                     <hillfox at fairpoint.net
>                                     <mailto:hillfox at fairpoint.net>>
>                                     Date: Mon, Sep 14, 2020 at 4:26 PM
>                                     Subject: another 24hour RM3100 run
>                                     and comparison with Fredericksburg
>                                     To: Kim, Hyomin <hmkim at njit.edu
>                                     <mailto:hmkim at njit.edu>>, David
>                                     Witten <wittend at wwrinc.com
>                                     <mailto:wittend at wwrinc.com>>, Dr.
>                                     Nathaniel A. Frissell Ph.D.
>                                     <nathaniel.frissell at scranton.edu
>                                     <mailto:nathaniel.frissell at scranton.edu>>,
>                                     Dave Larsen <kv0s.dave at gmail.com
>                                     <mailto:kv0s.dave at gmail.com>>
>
>                                     All,
>                                     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.
>
>                                     The vertical axes scales on all
>                                     plots are as close as I could
>                                     match them by eye in cutting and
>                                     pasting.
>
>                                     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.
>
>                                     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.
>
>                                     Jules - K2KGJ
>
>                                     -- 
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>
>
>                                 -- 
>
>                                 ----
>                                 Phil Erickson
>                                 phil.erickson at gmail.com
>                                 <mailto:phil.erickson at gmail.com>
>
>
>                         -- 
>
>                         ----
>                         Phil Erickson
>                         phil.erickson at gmail.com
>                         <mailto:phil.erickson at gmail.com>
>
>                     -- 
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