Audio output receivable with handheld radio

uConsole
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I have neither the equipment nor the know how to tell if this is an issue or just normal levels of interference but I have noticed that I can pick up the audio output of my uConsole as an FM signal at about 437.750 MHz. When audio is muted there is just one spike. Increasing volume results in a wider signal.

I have tested this with headphones plugged in and not plugged in. There is some difference but not a lot. I first noticed this when playing around with SDR++ (shout out to Rex for including it in the Bookworm build) but I have confirmed that I can also receive the audio of a Youtube video playing on the device without my SDR plugged in two rooms away.

I am using a CM5 and the only modifications I have made is a different WiFi antenna.

Could this be a result of the way audio was implemented for the CM5? Is this an issue or acceptable?

uconsole-screenshot
uconsole-screenshot981×682 204 KB

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It’s the PWM audio from the GPIO, it’s a side effect of the way we get audio. I guess the long traces going to the speakers act as a antenna.
You can even take a pi and make a little hacker radio station with it.

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That is kind of what I was expecting. Still amazing to me that I can actually pick it up and the audio is very intelligible. Just out of curiosity: why 438 MHz?

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:man_shrugging:
Not sure, antenna length probably. Just don’t text to speech your bank info! :rofl:

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I will start using bluetooth headphones when I listen to my social security number on repeat :wink:
I will also try doing a range test just for fun.

btw: thanks for all your amazing work!

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Thanks I appreciate it!
It had some surprising range on it when I tried with the Pi1 could go all around my acre property I had at the time.

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I saw the same thing. I took the Uconsole camping. I had my baofeng radio tuned to a NOAA channel. As soon as I powered on the Uconsole. NOAA became static.

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Radio amateur here, owner of a uConsole. I will use my ham radio test equip0ment and SDRs and scanners, but it probably won’t have enough range to cause problems. Off the top of my head, I think that is in the amateur 70cm band. I have a transceiver (receiver/transmitter) handheld, so can actually test this. Chances are, unless there is another radio amateur using 70cm very close to you, it won’t be picked up. Your house may well act as a Faraday cage, if there is metal inside the walls, but the power involved means you may find some rooms away from the uConsole you won;'t hear it inside your home. Look at it this way - if it doesn’t bother others, and you can set the uConsole to play music you can receive on a radio where you are, you have a wireless audio system!