[TangerineSDR] Raspberry Pi connectors produce magnetic interference

[Phil Erickson]

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
phil.erickson at gmail.com
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