Hi, I got interested on FM/DAB to renovate my previous built device, I have bought the V4 before and try to use in the raspberry pi 4, and find that most of them are background noise (with a very weak person speaking on channel), just like the channel not tuned in.
I have tried the following method,
Plug into a windows device, work like charm with airspy
Tried to use rtl_tcp in pi and read from windows airspy, strong signal as well
Asking AI, and just give me the advise of the pi power problem and the distance interference etc, following the advise and does not work. Even creating a cable to separate the power and data.
After playing around for a long time, and find that the DAC causing problem, as long as using analog to output, it just work fine, but using DAC hat (mine is hifiberry DAC), it will be noise everywhere, even using different sampling options,
Have anyone got DAC setup and it works fine? Thanks
As others have said, please be very wary of AI. When it doesn’t know something for certain, it can sometimes “hallucinate” and generate information that sounds convincing but is actually incorrect or entirely fictitious. The problem is that it often presents these answers with confidence, making it difficult to distinguish fact from fiction.
Your own tests already answered the AI for you. rtl_tcp from the Pi to Windows gave you a strong signal - that rules out Pi power, USB cable and antenna distance in one go. The AI advice was generic because it had nothing to work from. @Steve1 is spot on on the authoritative sounding nonsense. Same rule applies here: generic information gets a generic answer.
What your tests do show: the only thing that changes the result is the output device. Headphone jack good, HiFiBerry noise. That is worth chasing, but I will not guess at it. This thread has a reporting requirement (see previous posts) and it is not optional:
Plugin version (Settings > Plugins > Installed Plugins)
FM gain value you have set. The V4 wants around 70-80. At 20 it is deaf.
Is it FM only, DAB only, or both that are noisy on the HiFiBerry?
One comparison test. Play the same station on the headphone jack, then on the HiFiBerry. Tell me what the signal indicator in the Volumio playback screen shows in each case (colour or level). If it drops when the DAC is playing, the HAT is degrading reception. If it stays the same and only the audio is bad, the problem is on the audio side. Two different causes, two different fixes.
Independent of the above: move the dongle away from the Pi on a short USB extension and put a loop of the cable through a ferrite choke. A DAC HAT sitting a few centimetres from an SDR front end is a noise source by design, and this removes one variable for very little money.
With those five answers I can give you something specific. Without them I cannot.
