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<font face="Arial">Additional note on ferrous metal components; all
of my USB cables appear to have ferrous metal shells.<br>
Jules - K2KGJ<br>
</font><br>
<div class="moz-cite-prefix">On 5/29/2020 12:00 PM,
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr-request@lists.tapr.org">tangerinesdr-request@lists.tapr.org</a> wrote:<br>
</div>
<blockquote type="cite"
cite="mid:mailman.69.1590768003.10659.tangerinesdr_lists.tapr.org@lists.tapr.org">
<pre class="moz-quote-pre" wrap="">Send TangerineSDR mailing list submissions to
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To subscribe or unsubscribe via the World Wide Web, visit
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or, via email, send a message with subject or body 'help' to
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr-request@lists.tapr.org">tangerinesdr-request@lists.tapr.org</a>
You can reach the person managing the list at
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When replying, please edit your Subject line so it is more specific
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Today's Topics:
1. Re: TangerineSDR Digest, Vol 14, Issue 35 (David Witten)
----------------------------------------------------------------------
Message: 1
Date: Thu, 28 May 2020 11:28:56 -0500
From: David Witten <a class="moz-txt-link-rfc2396E" href="mailto:wittend@wwrinc.com"><wittend@wwrinc.com></a>
To: <a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr@lists.tapr.org">tangerinesdr@lists.tapr.org</a>
Subject: Re: [TangerineSDR] TangerineSDR Digest, Vol 14, Issue 35
Message-ID:
<a class="moz-txt-link-rfc2396E" href="mailto:CABJ3BVPHeA8XGa9RwvLEhotfDXSf4aDX4mh1g30vDihRoPLO1A@mail.gmail.com"><CABJ3BVPHeA8XGa9RwvLEhotfDXSf4aDX4mh1g30vDihRoPLO1A@mail.gmail.com></a>
Content-Type: text/plain; charset="utf-8"
NB:
Even the Simple Magnetometer Magnetometer Support Boards (SMSBs) should be
able to avoid this problem if attached using the Qwiic Cable - 500mm
<a class="moz-txt-link-rfc2396E" href="https://www.sparkfun.com/products/14429"><https://www.sparkfun.com/products/14429></a>, the Qwiic Cable - 200mm
<a class="moz-txt-link-rfc2396E" href="https://www.sparkfun.com/products/14428"><https://www.sparkfun.com/products/14428></a>, or their equivalents from
AdaFruit. I believe that I provided one or the other of these with any of
the boards I sent out for testing. Care in positioning is left up to the
user.
The problem probably only applies to upcoming raspberry-pi hats in local
mode (with the magnetometer sitting on top of the pi). But in some
non-professional cases, convenience may outweigh the loss of sensitivity,
esp functional testing.
People in the Drone community claim to have used uMetal for shielding to
good effect (from PM motors, etc) but this does not sound like good
practice for sensitive instruments.
And anyone using these boards in the remote extender configuration will
find it difficult to place the far end board that close with any amount of
shielded Cat-6 in between.
Dave
On Thu, May 28, 2020 at 11:00 AM <a class="moz-txt-link-rfc2396E" href="mailto:tangerinesdr-request@lists.tapr.org"><tangerinesdr-request@lists.tapr.org></a>
wrote:
</pre>
<blockquote type="cite">
<pre class="moz-quote-pre" wrap="">Send TangerineSDR mailing list submissions to
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr@lists.tapr.org">tangerinesdr@lists.tapr.org</a>
To subscribe or unsubscribe via the World Wide Web, visit
<a class="moz-txt-link-freetext" href="http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org">http://lists.tapr.org/mailman/listinfo/tangerinesdr_lists.tapr.org</a>
or, via email, send a message with subject or body 'help' to
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr-request@lists.tapr.org">tangerinesdr-request@lists.tapr.org</a>
You can reach the person managing the list at
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr-owner@lists.tapr.org">tangerinesdr-owner@lists.tapr.org</a>
When replying, please edit your Subject line so it is more specific
than "Re: Contents of TangerineSDR digest..."
Today's Topics:
1. Raspberry Pi connectors produce magnetic interference
(Phil Erickson)
---------- Forwarded message ----------
From: Phil Erickson <a class="moz-txt-link-rfc2396E" href="mailto:phil.erickson@gmail.com"><phil.erickson@gmail.com></a>
To: TAPR TangerineSDR Modular Software Defined Radio <
<a class="moz-txt-link-abbreviated" href="mailto:tangerinesdr@lists.tapr.org">tangerinesdr@lists.tapr.org</a>>
Cc:
Bcc:
Date: Thu, 28 May 2020 08:45:18 -0400
Subject: [TangerineSDR] Raspberry Pi connectors produce magnetic
interference
Hi all,
For those working on the PSWS magnetometer project, I'd like to pass
along some findings made by Nick Belsten (MIT student) on our AERO/VISTA
cube satellite team. As background, AERO/VISTA is a twin cubesat mission
with the goal of investigating the radio aurora at 400 kHz to 5 MHz in low
Earth orbit, and will fly in 2022 through the NASA Heliophysics small
satellite explorer program. MIT Haystack is the lead with MIT Lincoln
Laboratory providing the advanced electromagnetic vector sensor package.
Other participants include Dartmouth, Merrimack College, Morehead State
University, and MIT AeroAstro.
Each of the two cubesats will have an Auxiliary Sensor Package for
coincidence detection of the aurora (other than radio) that includes a
magnetometer. Nick has been in charge of some of the magnetometer
package development, and reports that stock Raspberry Pi connectors contain
steel that is magnetized and that causes deflections on the order of 2 uT
at 3 cm distance. Given scaling laws, it is therefore recommended to keep
the magnetometer at least 8-10 cm away from Raspberry Pi hardware to avoid
systematic bias or possible degradation in uncertainty if you are targeting
50 nT type measurement capabilities.
Nick is writing a memo on his findings and procedure so please contact
me off-list if you would like to hear from him directly.
Just an caveat / advisory note (perhaps not relevant) if anyone is
running a test configuration with magnetometers next to a R-Pi, rather than
at the end of a long cable. Perhaps it's also prudent to examine the
magnetic characteristics of connectors on the TangerineSDR?
73
Phil W1PJE
--
----
Phil Erickson
<a class="moz-txt-link-abbreviated" href="mailto:phil.erickson@gmail.com">phil.erickson@gmail.com</a>
TangerineSDR mailing list
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</pre>
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