Radio reception interference with wireless Raspberry Pi

Hello,


In my patio I have a car CD receiver hooked up to a car electric antenna, both sharing the same power supply (12V 4A, connected to mains).


A Raspberry Pi running Volumio is connected to the Aux input, via an external DAC, so I can listen to Spotify, local network MP3 files, etc., it uses its own 5V power supply, also connected to mains.



All installed inside a wood enclosure I built, will be able to attach pics if needed.


The problem is with radio reception interference, only when the Rpi is on.
I believe that what's causing the interference is the Rpi's Wifi / Bluetooth interfaces.


When I turn the RPi off, reception is clean, no interference at all.
I tried grounding the receiver's enclosure to the mains ground, tried using a ground loop isolator, and also tried with and without the external DAC.



Any help will be much appreciated.


Best,


Shahar
 
If the pi is using a 5v supply, can you get that from the USB/aux of the HU? If not, try tying the ground/shield of the pi signal to the outside case of the radio. Cross fingers. 12v audio stuff doesn't play well with multiple power sources esp main through different transformers. It would be better to power up the pi from the same source, or from the HU I would think. OR, make the pi run audio over bluetooth in isolation.
 
Do you still have the interference when the Raspberry Pi is on, but not connected to the radio? If not, some clip-on ferrite beads on the cable between them might help, as well as grounding the cable to the case of the radio like Dr Zeus wrote. If you still have the interference with a disconnected Raspberry Pi, it may get difficult as you can't easily shield the Wifi, Bluetooth or radio antennas.
 
Do you still have the interference when the Raspberry Pi is on, but not connected to the radio? If not, some clip-on ferrite beads on the cable between them might help, as well as grounding the cable to the case of the radio like Dr Zeus wrote. If you still have the interference with a disconnected Raspberry Pi, it may get difficult as you can't easily shield the Wifi, Bluetooth or radio antennas.


Yes I have the interference when it's not connected. Tried grounding the cable to the radio, put ferrite beads on the wires but it didn't work unfortunately.
 
If the pi is using a 5v supply, can you get that from the USB/aux of the HU? If not, try tying the ground/shield of the pi signal to the outside case of the radio. Cross fingers. 12v audio stuff doesn't play well with multiple power sources esp main through different transformers. It would be better to power up the pi from the same source, or from the HU I would think. OR, make the pi run audio over bluetooth in isolation.


I cannot get 5V from the HU, but will try using the HU power supply to provide the pi 5V using a regulator circut. Will keep you posted.
 
As was suggested, separating the RPi from the head unit may help. If distance does make a difference, is it the distance from the RPi to the case of the head unit or the distance from the RPi to the antenna?

Are you using a standard antenna with a shielded cable?


In order to determine whether it is the distance from the head unit or from the antenna I have to remove the antenna from the enclosure, will try it later on today and report back.
 
Unlikely coming from the wifi or bluetooth, probably from either the switching power supplies or noise from the high speed data buses. Using a faraday cage won't prevent the noise getting into the head unit because its going via the antenna input.
If anything you'll need to put the Rpi into a separate aluminium enclosure.
 
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Hello Everyone

Came across this posting whilst doing a bit of research for the same issue.

I have a VHF radio hooked up to a raspberry pi via a line in so I can listen in on a zello channel and no matter what I do, the radio goes mad with interference. I know its coming from the Pi because the moment I shut the pi down, its like throwing a switch - The interference stops. If I start the Pi up, interference starts

Des anyone know if putting the pi into a separate aluminium enclosure has done the trick?