Some missing features

[vaisala]

#After a few days of using the RTLSDR-Airband seems a great project but I find that I need some functions not available, mainly related to the recording or scanning.

A small list functions that are missing:

• Possibility of referring to the dongles by their serial number
• Squelch delay selectable in seconds for scan mode.
• Selectable file recording rotation (on every transmission, every hour, every day, every week, and one single file)
• File recording in scan mode to separate files by channel/freq
• FM bandwidth configurable for better reception of narrowbanded pmr, commercial radio, etc. ( This maybe can helps with the problem i have in NFM bleeding audio/noise even after setting low gain values)
• Support for other SDRs HW with higher bandwidth, eg Airspy
• Realtime raw output ¿ALSA loopback devide? to stream with external software (mumble) or pipe to software decoders (for acars, pocsag, etc) and/or Raw file output (wav) that allows the offline data decoding.

I am aware that some functions are more complicated to implement than others. I'm sorry cant collaborate directly but C++ is not a familiar language for me, however I am willing to provide testing for the functions that come to be implemented.

[szpajder]

• referring to the dongles by their serial number - will do, it's already on my TODO list
• selectable squelch delay, separate files by channel/freq in scan mode - rather impossible with current implementation of scan mode, needs a rework first
• selectable file rotation interval - looks feasible
• configurable FM bandwidth - not possible, with FFT channelizer the channel bandwidth is fixed. There is no filtering at all.
• Airspy - hm, maybe. I don't have this hardware at hand.
• output to ALSA - will do, it's already on TODO.
• pipe to software decoders - not worth the effort. RTL dongles are so cheap, that you could just buy another one and do ACARS on it.

[tnadolecki]

"pipe to software decoders - not worth the effort. RTL dongles are so cheap, that you could just buy another one and do ACARS on it." -- this could be achieved by outputing audio to a virtual audio device, then make acars decoder read that virtual device - in the future of course - when audio output is ready.

[dranch]

If I connected an Airspy to an externally available SSH host, would that be enough for you to make progress? If not, maybe we could work with the Airspy folks to get you a loaner or old prototype that would function well enough for your coding needs.

[szpajder]

Right now it's not necessary. I'd rather go for a SoapySDR interface (see also #60), which would make the code hardware agnostic.

[tnadolecki]

Possibility of referring to the dongles by their serial number

Please....

[szpajder]

Serial numbers are now supported in unstable branch. Apologies for delay.

Quick HOWTO - instead of:

index = 0;

specify:

serial = "0123456";

[tnadolecki]

Working flawlessly, thank you !!!

Jun 13 10:47:13 raspberrypi rtl_airband[24718]: Device #2: gain set to 25.40 dB
Jun 13 10:47:13 raspberrypi rtl_airband[24718]: Device 2 started.
Jun 13 10:47:13 raspberrypi rtl_airband[24718]: Device #0: gain set to 25.40 dB
Jun 13 10:47:13 raspberrypi rtl_airband[24718]: Device 0 started.

[vaisala]

Thank you very much.

[USAFPride]

Serial working for me. serial = "liveatc"

[Adraenyse]

Selectable file recording rotation (on every transmission, every hour, every day, every week, and one single file)

I don't see anything about this in the documentation yet - do you have a recommendation on how to forcibly rotate the files in the meantime? I tried to steal the recording manually to see if it would recreate it but it doesn't appear to.

[szpajder]

Nope, currently there are no other rotation triggers, except of time. Right now I'm working on variable source rates and FFT sizes, so that support for radios other than RTL could be added. Recording improvements will come after that.

[szpajder]

• Support for other SDRs HW with higher bandwidth, eg Airspy - available in 3.0.0, via SoapySDR library.
• FM bandwidth configurable for better reception of narrowbanded pmr, commercial radio, etc. ( This maybe can helps with the problem i have in NFM bleeding audio/noise even after setting low gain values) - 3.0.0 supports configurable sampling rate and FFT size, which may help in such cases; see also the Troubleshooting section in the wiki.
• Realtime raw output "ALSA loopback device" to stream with external software (mumble) or pipe to software decoders (for acars, pocsag, etc) and/or Raw file output (wav) that allows the offline data decoding - piping audio to other apps may be accomplished with Pulseaudio and module-pipe-sink (available since 2.4.0, see also [Feature Request / Suggestion] Output to loopback #43 (comment)); rawfile output is available in 3.0.0 (refer to the docs for details)).