[TangerineSDR] TangerineSDR Digest, Vol 27, Issue 3 - Magnetometer
David G. McGaw
david.g.mcgaw at dartmouth.edu
Wed Jun 2 10:49:31 EDT 2021
The magnetometer boards use linear regulators. The magnetometer itself
has a switching component. I have been meaning to test it for radiation
and develop appropriate shielding if necessary.
David N1HAC
On 6/2/21 10:40 AM, Jonathan via TangerineSDR wrote:
> I’ll have to double check the schematic, but I don’t think there are
> any switching regulators on the magnetometer board. The noise could be
> coming from the i2c clock or possibly the internal clock of the
> magnetometer IC.
>
> Jonathan
> KC3EEY
>
> On Jun 2, 2021, at 9:50 AM, Ward Silver via TangerineSDR
> <tangerinesdr at lists.tapr.org <mailto:tangerinesdr at lists.tapr.org>> wrote:
>
>> Was the test unit powered by a switching power supply module? If so,
>> replacing it with a linear supply might help.
>>
>> In a "production configuration" we should recommend shielded CAT5 or
>> CAT6 cable with type 31 ferrite beads or cores on each end of the
>> Ethernet cable. If practical, a linear power supply should be used
>> for both the magnetometer module and the host SDR. There are clean
>> switchmode supplies, as well, but they would have to be tested.
>>
>> If the noise is being radiated directly from the electronics, we'll
>> have to tackle that separately.
>>
>> 73, Ward N0AX
>>
>> On Wed, Jun 2, 2021 at 8:39 AM Dr. Nathaniel A. Frissell Ph.D.
>> <nathaniel.frissell at scranton.edu
>> <mailto:nathaniel.frissell at scranton.edu>> wrote:
>>
>> Hi Bill,
>>
>> Thank you for that evaluation, and like Ward, I am glad to hear
>> the magnetometer does not appear to be sensitive to RF. I’m
>> sorry to hear about its effects on 80 and 160 m, and I guess that
>> will need to be discussed some more.
>>
>> 73 Nathaniel W2NAF
>>
>> —
>> Dr. Nathaniel A. Frissell, Ph.D., W2NAF
>> HamSCI Lead
>> Assistant Professor
>> Department of Physics and Electrical Engineering
>> University of Scranton
>> (973) 787-4506
>>
>>> On Jun 1, 2021, at 10:09 PM, Ward Silver via TangerineSDR
>>> <tangerinesdr at lists.tapr.org
>>> <mailto:tangerinesdr at lists.tapr.org>> wrote:
>>>
>>> Glad to hear of the insensitivity to ambient RF at a variety of
>>> frequencies, Bill!
>>>
>>> This brings up the system-level issue of RFI created by the PSWS
>>> as conducted emissions, most likely. It would be a problem if
>>> the PSWS interferes with its own local receiver! So we (meaning
>>> the design team) will need to carefully evaluate the I/O and
>>> power lines to be sure they are RF-quiet. I can probably help
>>> with that as I am winding down a series of back-to-back-to-back
>>> book projects and have some time coming up.
>>>
>>> 73, Ward N0AX
>>>
>>> On Tue, Jun 1, 2021 at 9:00 PM
>>> <tangerinesdr-request at lists.tapr.org
>>> <mailto:tangerinesdr-request at lists.tapr.org>> wrote:
>>>
>>> Send TangerineSDR mailing list submissions to
>>> tangerinesdr at lists.tapr.org <mailto:tangerinesdr at lists.tapr.org>
>>>
>>> To subscribe or unsubscribe via the World Wide Web, visit
>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fmailman%2Flistinfo%2Ftangerinesdr_lists.tapr.org&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738745769%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=xHyz0ugL4zWvIVn1nSdOY29U3hXdvw7Pn1lx9rNrSS4%3D&reserved=0>
>>> or, via email, send a message with subject or body 'help' to
>>> tangerinesdr-request at lists.tapr.org
>>> <mailto:tangerinesdr-request at lists.tapr.org>
>>>
>>> You can reach the person managing the list at
>>> tangerinesdr-owner at lists.tapr.org
>>> <mailto:tangerinesdr-owner at lists.tapr.org>
>>>
>>> When replying, please edit your Subject line so it is more
>>> specific
>>> than "Re: Contents of TangerineSDR digest..."
>>>
>>>
>>> Today's Topics:
>>>
>>> 1. Magnetometer RF testing, additional results (Bill Engelke)
>>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Tue, 1 Jun 2021 16:15:00 +0000
>>> From: Bill Engelke <bill.engelke at ua.edu
>>> <mailto:bill.engelke at ua.edu>>
>>> To: TAPR TangerineSDR Modular Software Defined Radio
>>> <tangerinesdr at lists.tapr.org
>>> <mailto:tangerinesdr at lists.tapr.org>>
>>> Subject: [TangerineSDR] Magnetometer RF testing, additional
>>> results
>>> Message-ID:
>>>
>>> <BN8PR15MB31855B741907BD4C37902902FA3E9 at BN8PR15MB3185.namprd15.prod.outlook.com
>>> <mailto:BN8PR15MB31855B741907BD4C37902902FA3E9 at BN8PR15MB3185.namprd15.prod.outlook.com>>
>>>
>>> Content-Type: text/plain; charset="us-ascii"
>>>
>>> Here is a follow-up to my last email regarding possible RF
>>> interactions with the magnetometer. A couple of suggestions
>>> came in from the community:
>>>
>>>
>>> 1. Ward Silver, N0AX, recommended to test by transmitting
>>> with a dipole near the magnetometer in several
>>> configurations, on 2 meters with 50 w.
>>> 2. Tom McDermott, N5EG, recommended to look for RF noise
>>> being generated by the magnetometer that might get into your
>>> station receiver.
>>>
>>> Here are results of doing such tests:
>>>
>>>
>>> 1. I built a 2-m dipole specifically for this so that I
>>> could test with the antenna (a)broadside to the
>>> magnetometer, (b)vertical to it, and (c) pointed towards it.
>>> (photos) The antenna was located about 10 feet from the
>>> magnetometer, which is buried at 2 feet in the soil (its
>>> standard installation as tested by Jules and others), and
>>> connected to the station with shielded CAT-6.
>>>
>>> Broadside configuration
>>>
>>> [cid:image004.png at 01D756D6.2EB4CD30]
>>>
>>> Vertical configuration:
>>>
>>> [cid:image005.png at 01D756D7.049AA500]
>>>
>>> Straight-on configuration
>>>
>>> [cid:image006.png at 01D756D7.049AA500]
>>>
>>> The antenna was connected via a new 50 foot RG-8 cable to an
>>> Icom IC-706MKIIG, set to high output (50 watts), 145 MHz. I
>>> did my best to do what Ward suggested.
>>>
>>> Results: I never saw the magnetometer readings change when I
>>> keyed the rig; this was the same for the 3 different antenna
>>> angles. I have to conclude that the magnetometer is not
>>> sensitive to 2 meters.
>>>
>>>
>>> 1. Using the FlexRadio 6600, I looked for noise being
>>> generated by the magnetometer on all ham bands from 160 m to
>>> 10 meters. I looked for wide band noise by watching the
>>> waterfall and turning the magnetometer on and off. If I saw
>>> noise appear, I tried turning the magnetometer off and on to
>>> see if the noise would come and go with being connected to
>>> the magnetometer base card on the Raspberry Pi. I used the
>>> appropriate antenna for each band (i.e., the one I use for
>>> my station), as follows: (160 M) - multiband vertical,
>>> (80M) halfwave dipole at 15 ' (20 feet away) and also
>>> multiband vertical about 50' away, (60M) multiband vertical,
>>> (40 M) double bazooka inverted vee, (20M through 10 M) DX
>>> Engineering Hexbeam on 50' tower.
>>>
>>> Results: First the good news: I never saw wideband noise
>>> attributable to the magnetometer on the bands 60 meters and
>>> higher in frequency. I did see noise on 80M and on 160M.
>>> The magnetometer does generate noise of about 0.4 db as
>>> shown on the FlexRadio s-meter on 80M. (Note that this is a
>>> severe case, as the 80 M dipole is only up 15' and about 20'
>>> away from the magnetometer - but this is probably a typical
>>> situation). On 160 M, the magnetometer generated 1 db of noise.
>>>
>>> Screenshot of 80 M result using dipole
>>>
>>> [cid:image001.png at 01D756D4.9FD34E80]
>>>
>>> Screenshot of 80 M on multiband vertical
>>>
>>> [cid:image002.png at 01D756D5.12202BC0]
>>>
>>> Screenshot of 160 M, multiband vertical
>>>
>>> [cid:image003.png at 01D756D5.6F866360]
>>>
>>> I suppose that we would recommend turning off the
>>> magnetometer if you are working DX on 80 Meters; possibly
>>> separating the magnetometer from the antenna might also
>>> help, but I was not able to test that.
>>>
>>> -73- Bill, AB4EJ
>>> -------------- next part --------------
>>> An HTML attachment was scrubbed...
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment.html
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment.html&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738755729%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=weuuFI7BJudb%2F2X83Up36t3fw5s4PACX5zhY7AICogE%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image001.png
>>> Type: image/png
>>> Size: 704614 bytes
>>> Desc: image001.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738755729%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=QbS%2Bc%2B7tdBJEJSuu58m6F9oWF%2FAUI5B6b7t3r7izaUI%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image002.png
>>> Type: image/png
>>> Size: 570271 bytes
>>> Desc: image002.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment-0001.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment-0001.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738765683%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=jOCKumdPs6JK%2B0qjduAM8O48abrBn7Vs9FURoEHezJs%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image003.png
>>> Type: image/png
>>> Size: 567390 bytes
>>> Desc: image003.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment-0002.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment-0002.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738775638%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=rikLwsYyRWsdBCDZ1g9%2F8qYoEdELyjFix6%2FT5YsHG%2BE%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image004.png
>>> Type: image/png
>>> Size: 881003 bytes
>>> Desc: image004.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment-0003.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment-0003.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738775638%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wQbAgCqlbu87cjGGcOVjDk5e%2BVhvviv7jv4w%2B8NRmq4%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image005.png
>>> Type: image/png
>>> Size: 1110976 bytes
>>> Desc: image005.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment-0004.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment-0004.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738785594%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=5rTH9YKwv1Vl8yU2SFu%2BVK7XXA4495EO7utUhrgtEkg%3D&reserved=0>>
>>> -------------- next part --------------
>>> A non-text attachment was scrubbed...
>>> Name: image006.png
>>> Type: image/png
>>> Size: 985870 bytes
>>> Desc: image006.png
>>> URL:
>>> <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210601/1d5000a4/attachment-0005.png
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fpipermail%2Ftangerinesdr_lists.tapr.org%2Fattachments%2F20210601%2F1d5000a4%2Fattachment-0005.png&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738785594%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=NqCcvaqPmZ5fFOotnI5E73oUDUD5%2BaCV8cEhwfJfRb0%3D&reserved=0>>
>>>
>>> ------------------------------
>>>
>>> Subject: Digest Footer
>>>
>>> TangerineSDR mailing list
>>> TangerineSDR at lists.tapr.org <mailto:TangerineSDR at lists.tapr.org>
>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fmailman%2Flistinfo%2Ftangerinesdr_lists.tapr.org&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738795555%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=rXkGqJCFJGMvG8FpkHT1fkKqby88AuCrH%2Fk1p%2FCsUe4%3D&reserved=0>
>>>
>>>
>>> ------------------------------
>>>
>>> End of TangerineSDR Digest, Vol 27, Issue 3
>>> *******************************************
>>>
>>> --
>>> TangerineSDR mailing list
>>> TangerineSDR at lists.tapr.org <mailto:TangerineSDR at lists.tapr.org>
>>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fmailman%2Flistinfo%2Ftangerinesdr_lists.tapr.org&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738795555%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=rXkGqJCFJGMvG8FpkHT1fkKqby88AuCrH%2Fk1p%2FCsUe4%3D&reserved=0>
>>
>> --
>> TangerineSDR mailing list
>> TangerineSDR at lists.tapr.org <mailto:TangerineSDR at lists.tapr.org>
>> http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org
>> <https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.tapr.org%2Fmailman%2Flistinfo%2Ftangerinesdr_lists.tapr.org&data=04%7C01%7CDavid.G.McGaw%40dartmouth.edu%7Ce1a97fb22d0c4503fd4108d925d47762%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637582416738805503%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=rjmXJVxEqOihImvoPQTe%2BjzJMmilwniwy1ZPzT992HY%3D&reserved=0>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.tapr.org/pipermail/tangerinesdr_lists.tapr.org/attachments/20210602/507c66fd/attachment-0001.html>
More information about the TangerineSDR
mailing list