[arm-allstar] Solved! RF getting into Node Processor

[John Baxter]

Hello,

Today I learned a number of highly valuable lessons that center on keeping RF out of your Node Processor (Raspberry Pi and peripheral wiring).

John WA3EZT was kindly helping me to test the audio on my newly-reconfigured AllStar node (using a Yaesu FT-7900 transceiver).   WA3EZT was guiding me through audio setup, since I could just never get it to sound good.  We were doing everything correctly in simpleusb but the Receive audio (from the Node receiver to the Internet) was muffled and terrible.

I was sure it was something wrong with my Yaesu FT-60 HT.  It has hundreds of menus with roughly the complexity of the SpaceX Starship, so I was sure something, somewhere was misconfigured or maybe even some hardware had failed.  I tried three different speaker-mikes.  No Joy!!! Lousy Audio!!!

Went out to the Car and Audio was good!!  Even stranger, out in the car we did an A/B test between the HT and the Car, and BOTH sounded good (???!!!)  It was then that WA3EZT wisely suggested that RF from my HT was getting into the Pi when I transmitted near it!!!  Suddenly it was clear - I had to avoid that kind of trouble by transmitting from a bit more distance from the Pi.

Have temporarily simply moved my operating position upstairs away from the Pi.  It was suggested that I put the Pi in a Faraday Cage to shield it from RF, but this could result in overheating.  Best to simply keep it away from strong RF fields as much as possible.  (Similarly, do NOT use a Rubber Ducky on a Baofeng for a portable node.  Use an External Antenna, and follow smart RF layout, shielding and grounding practices - play by the Rules of Physics!!!)

This was a really excellent learning experience…

Sincere thanks to John WA3EZT for his patience and guidance…

73,
-john N3FPZ

John William Baxter	jwilliambaxter at me.com <mailto:jwilliambaxter at me.com>
BAXTERTECH creating ways to connect
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N3FPZ				amateur radio / Allstar node: 45506


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