Will autoscan and tune into the most powerful AM broadcast up in the skies for a large frequency range wherever you tune your RTL dongle or other SoapySDR compatible device.
Edit the Soapy RTLDSR Source block -> Device Arguments in gnuradio_companion as needed
e.g. for a local RTL SDR:
rtl=0
e.g. SoapyRemote device:
remote=192.168.1.50,driver=remote,remote:timeout=100000,remote:driver=rtlsdr,rtl=0
Audio can be heard either through the local default sound card or remotely by starting VLC player on the host corresponding with AudioStreamIP using AudioPort as defined in the gnuradio sketch.
e.g. as in the defaults, on 127.0.0.1 type:
vlc -I dummy --demux=rawaud --rawaud-channels=1 --rawaud-samplerate=48000 udp://@:7355
Edit the Soapy RTLDSR Source block to meet your needs as outlined above.
Then:
bash ./start.sh
2024-05-01 11:48:52,306 [INFO] Waiting to connect to gnuradio sketch ...
2024-05-01 11:48:52,349 [INFO] Connected gnuradio sketch
2024-05-01 11:48:55,720 [INFO] Tuned to am channel 134.90
2024-05-01 11:49:01,731 [INFO] Tuned to am channel 135.00
bash ./end.shTested on Ubuntu 22.04.4 (GnuRadio 3.10). Should also work on 3.9 but not below that.
sudo apt-get install gnuradio soapysdr-module-all rtl-sdrFor SoapyRemote
sudo apt-get install soapyremote-server soapysdr-module-allFor remote audio client
sudo apt-get install vlc
| Item | Description |
|---|---|
| tuning_freq | Coarse tuning into the frequencies of interest, in 1MHz jumps. For example selecting 135000000 (135MHz) will let you listen in on activity within 134 MHz and 136 MHz. |
| gain | Tune this using the Power/Frequency graph in the user interface so that you see decent audio signals (the large upward spikes) appear on the graph above the noise floor. |
| carrier_squelch | Set this to the lowest power level (as in the displayed graph) of signals you want to listen to, bigger values have a better signal to noise ratio and sound clearer. |
| hold_seconds | Do not tune into another concurrent (albeit higher signal to noise) audio channel for this interval (prevents rapid flipping between channels). |
| AudioStreamIP | IP to push raw remote audio |
| AudioStreamPort | Port to push raw remote audio |
| samp_rate | SDR sample rate |
| ppm | SDR frequency error value |
You can still run the flow graph airbandtuner.grc in gnuradio-companion without running airbandtunerclient.py as well, it just will not auto tune into the audio.
I decided to delegate processing of the FFT for channel selection over the network to a custom python program as unfortunately the built in GNURadio Max() block is no use as you need the index from the FFT for tuning as well as the power value.
There are upsides to this though ...
- CSV file of useful stats e.g. frequency, timestamp, power, talk-duration (for all concurrent channels).
- Radio frequency name identification based on your location and harvested frequency name guide databases.
- Speech to text, then hooks to flights on ADSB exchange!
Please do email JoeTester1965 at email dot com with any questions.