Remote recording of FM radio

Discussion in 'Coding, Scripting & Programming' started by MartinD, Apr 18, 2016.

  1. MartinD

    MartinD Retired Staff Retired Staff Verified Provider

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    Working on a solution where I have a RasPi in a remote location to record FM radio (certain times, certain length of time) using an rtl2832u stick. This would then be sent (or fetched) via a network connection to a central location.


    Anyone have any suggestions and/or ideas on what software they'd use in a similar situation?


    I'm eyeing up the ftl_fm stuff and perhaps VLC too.. but open to suggestions :)
     
  2. drmike

    drmike 100% Tier-1 Gogent

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    arecord probably with a cronjob that files, runs for duration then dies where another one then fires off with a new time + data stamped file...


    ffmpeg is capable also.



    Old and moldy, but still valid:
    http://mocha.freeshell.org/audio.html
     
  3. MartinD

    MartinD Retired Staff Retired Staff Verified Provider

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    Using rtl_fm and aplay :)


    Testing on rpi model a at the no and my pi 3 should arrive tomorrow! 
     
  4. drmike

    drmike 100% Tier-1 Gogent

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    You could do the whole Shoutcast or similar Icecast on the Pi and on your remote end have an audio catcher like streamripper running and cutting the audio down to files for archiving.   Depends on your intended use though.


    Have used everything except rtl_fm in the past to hack things together.


    Interested in hearing what you cobble and what makes run when done.  Interesting project :)
     
  5. MartinD

    MartinD Retired Staff Retired Staff Verified Provider

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    Shoutcast wouldn't work really. 


    I've gone for rtl_fm, Sox and avconv to record radio at a specific time, for a specific length, convert and send 'home'. Wrote a handful of scripts to control it all and its working well. 


    Just to note, when I said remote location, I didn't just mean 'not here, not local' I meant in the middle of nowhere :) 


    Now experimenting with a pvr solution for the same though I think my cli version is better. 


    Will have to go and install these too eventually in to the wilderness! 
     
  6. MartinD

    MartinD Retired Staff Retired Staff Verified Provider

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    Also, the raspi 3 is a brilliant piece of kit! 
     
  7. markhascole

    markhascole New Member

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    hahaha FM radio once upon a time
     
  8. wlanboy

    wlanboy Content Contributer

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    I am working on a remote videocam based on a Raspberry Pi. There is a Raspberry Pi Cam version without IR filter.
     
  9. coreyman

    coreyman Active Member Verified Provider

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    Why do you only need to record for a specific time for a specific length of time instead of all the time? Seems odd.
     
  10. MannDude

    MannDude Just a dude vpsBoard Founder Moderator

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    MannDude
    Couldn't you use a RTL-SDR usb dongle to achieve this?

    I use one to monitor the 2M/70cm amateur radio bands around me but I can also tune it to FM stations and record them to file if I wish.

    I use Gqrx on Linux to achieve this.

    NaPC8Z5.png

    That's me monitoring a local station that I can actually receive down here in the valley. Like I said above, I typically use this to monitor 144.000 MHz to 146.000 MHz and 430.000 MHz to 440.000 MHz frequencies but it'll work for what you intend to do with it.
     
    Last edited: May 5, 2017
  11. scv

    scv Massive Nerd Verified Provider

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    scv
    I'm surprised how clear that signal looks despite you having the hardware AGC enabled. Those spurs are present since the AGC is overdriving the crap out of the poor thing. Best luck I've had is between 9-17dB gain manually configured. Even then my non-TXCO sticks still show tons of spurious garbage like this:

    49c35368c82ca7169d553c2ca99fdb78.png

    Pretty sure it's a harmonic of the stick's internal clock, considering it's still fairly visible without anything in the MCX connector and I don't see anything on a nicer dongle with better shielding. But hey, they're cheap, who cares? ¯\_(ツ)_/¯
     
  12. WasNotWSS

    WasNotWSS Member

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    WalkTheDinosaur
    Tracking the Russian Woodpecker mk2?

    Wait, no.. FM, FM..
     
  13. MannDude

    MannDude Just a dude vpsBoard Founder Moderator

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    Unrelated, but sort of related: It'd be neat to find a transmitter using only some SDR receiver in a sort of fox-hunt, geocaching, scavenger hunt type thing.

    No audio, just roam around with some sort of yagi antenna until you start to receive the faintest glimpse at what appears to be a signal on your waterfall. Then follow.
     
    WasNotWSS likes this.