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Cool! I last played with it a couple of years ago. Will have to mess with it again. Great work! Do you know if the newer versions of RPi or other small boar
by madengr 10y ago
Cool! I last played with it a couple of years ago. Will have to mess with it again. Great work!
Do you know if the newer versions of RPi or other small boards have enough power to run this (i.e. dedicated RX feed nodes sort of like the ADSB RX nodes)? I know DSD is pretty processor intensive.
- robotastic 10y agoThanks! So I have been playing with it on a RPi3. There are instructions here on how to build for the RPi: https://blog.hypriot.com/post/building-a-64bit-docker-os-for-rpi3/ https://blog.hypriot.com/post/building-a-64bit-docker-os-for... It has about enough CPU to handle recording about 2 streams at the same time. I think part of the problem is that Raspbian does not have the GCC flags optimized for the processor in the RPi3 and doesn't have 64bit enabled. I played a little with this image: https://blog.hypriot.com/post/building-a-64bit-docker-os-for-rpi3/ https://blog.hypriot.com/post/building-a-64bit-docker-os-for... and it seemed to help a bit, but I didn't see huge gains. People are using it with the ODroid, and I think they are able to do about 4 simultaneous recordings at the same time.
- madengr 10y agoAre you using polyphase channelizer now, as opposed to individual XFIR tuners? If so, does that still provide better performance given sparsely occupied channels?
- robotastic 10y agoUnfortunately, I wasn't able to find a nice generic way to make it easy to configure the PFBs. There is a good thread on it here, with some sample code: https://github.com/robotastic/trunk-recorder/issues/76 https://github.com/robotastic/trunk-recorder/issues/76 If I can get a block of free time I am going to try and take another tilt at it. I did switch to FFT based filters and that helped a lot. CPU requirements are a lot less. Using RTLs with 2M sample size, instead of SDR more bandwidth also helps. It is a poor mans version of HW-based channelization.
- robotastic 10y agoThere is also this Rust based P25 decoder that I have been wanting to give a try: https://github.com/kchmck/p25rx https://github.com/kchmck/p25rx It is a ground up re-write that doesn't need Gnuradio, so it could be pretty efficient.
- SpikedCola 10y agoI've used Raspberry Pis for this, but they tended to be bulky and overkill - the "Banana Pi Zero" is what I've been using lately. Combined with a PoE splitter (some have micro-usb, you can plug directly into the board), this works great - no more coax losses! I use one for SDR playing, and one for receiving OTA ATSC and streaming to Kodi. I suppose I could have also installed a USB hub and run them both (or more) from one board.
- matheweis 10y agoBanana Pi Zero? What board is that? (I've been experimenting with various board for a project, so genuinely interested if this isn't a typo)
- enzanki_ars 10y agohttp://www.banana-pi.org/product.html http://www.banana-pi.org/product.html
- matheweis 10y agoThanks - but which one is the zero?
- SpikedCola 10y agoI'm sorry, it's an "Orange Pi Zero"[1] that I'm using, not a "Banana Pi Zero". I've gone through so many of these dev boards that it's hard to keep them all straight! [1] http://www.orangepi.org/orangepizero/ http://www.orangepi.org/orangepizero/
- matheweis 10y agoAh ha, thanks - I actually own two of those! They are awesome little boards, except for the wifi which is borderline unusable.
- jeffdubin 10y agoWould love to know more about OTA ATSC on Raspberry/Banana Pi -- everything I read tends to say that these ARM-based boards are good for playback only.