Yeah, nice, a full animal corpse, from a environment and price where u can taste that antibiotics, who would not wana bite right into that...
einfach_orangensaft
joined 1 year ago
12
Using SDRangel and multimon-ng to decode multiple parallel POCSAG signals with only one RTL SDR stick
(lemmynsfw.com)
If you are not familiar with POCSAG or its usage check out [https://en.wikipedia.org/wiki/DAPNET](Decentralised Amateur Paging Network) .
This is a little write up on how to use SDRangel and multimon-ng to decode multiple parallel POCSAG signals with only one RTL SDR stick.
This happens in a Linux environment, not sure if this will work on windows.
- Install SDRangle, multimon-gn and sox
- Open SDRangle and select your SDR as source.
- Select your desired Frequency and find your POCSAG signals using the waterfall display
- Activate AGC
If you want to listen to the signal only without decoding:
- Press the add channel button and Select "NFM Demodulator"
If you want to decode the POCSAG using SDRangel's internal Demodulator:
- Press the add channel button and Select "Pager Demodulator"
SDRangel's internal Demodulator works, but it only decodes 512 or 1200 or 2400 baud POCSAG. Meaning if you have 3 frequency's, each carrying 521 and 1200 baud signals, you would need 6 decoding windows in your SDRangel's work environment.
But there is a more easy way to do this, multimon-ng.
How to use SDRangel with multimon-ng:
- Press the add channel button and Select "UDP sample sink"
- In the UDP window, center the desired frequency
- Set the settings:
This will generate a UDP stream on port 7355 for multimon-ng to decode.
To decode open a terminal and use this chain of commands:
nc -l -u -p 7355 | sox -t raw -esigned-integer -b 16 -r 48000 - -esigned-integer -b 16 -r 22050 -t raw - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 - | tee freqlog_1.txt
This is what it does: "nc -l -u -p 7355" pipes in the UDP sound frames, "sox" converts the input to something usable for multimon-ng, "multimon-ng" attempts decoding and puts out text "tee" display the outputs in the terminal while also logging to a text file
To decode multiple signals in parallel, open another UDP Sample sink window with the same settings but change the port to 7356, then again center your desired frequency.
Open another terminal and repeat the command chain, but replace 7355 with 7356 and increase the number in the log file name by one.
You can do this with as many signals as you want, as long as they are in the same Bandwidth your SDR is set, for a cheap SDR stick you may watch everthing that happents in a 2Mhz window, with a better one you can do 20Mhz or more.
Now you should have open multiple terminals, each logging its own frequency, but how to pipe that into one terminal so you dont have to switch?
tail -f freqlog_1.txt freqlog_2.txt freqlog_3.txt
This watches for changes in the end of the log files and pipes it all in one terminal.
Thats it for my write up, now have fun decoding.
Ima try to analyze this piece of art:
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First impression upper middle: The Rafale is looking cute and sleek, the side perspective sets emphasis on the form that was build to go fast.
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Middle right: Here we see the Rafale snoozing in the grass wich implies it is very comfy with operating from make shift airfields and dosent mind sleeping outside over night.
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Middle left: Using the hypothetical tongue of the airplane, the artist tryes to convey the warm and embracing feeling the plane give to the pilot when the flight suit gets pressurized with by the jets air compressor.
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Lower Left: Here can we see the Rafale playing with a Tree, probably a reference to the plane loving to fly ground hugging and nicking a treetop here and there.
I love that guys channel, genuine good soul person
I think it could be done, just a matter of time and tools.
I have tryed this tool here https://nsspot.herokuapp.com/imagetoaudio/ when take a picture of the waterfall display, then invert it with krita and send it thru the converter a second time. Problem is that is rather crude, it makes the pixels in wich i can take the screenshot the bottle neck and the results are not fine enough for musik.
Have fun with reaper, i am a total audio noob so i have been playing with it for a few days but still discover new stuff constantly :D
The project is to invert the MFSK-64 protocol, its used to send text over Ham radio (in this case i generate the tones with Fldigi). I want to make a fusion between data and music. But the tones itself would be rather annoying to listen to, so my idea was to send "sound holes" where the tones would be, and then to decode holes instead of tones. This would allow me to use any music i want, and just encode the data into the holes, a song missing a few frequency's here and there is still listnable.
i feel maybe i should just try to convert the audio into some fft file and then see if i can somehow invert the values in that file with a script
guess it cant be done
I am also trying with Reaper right now, sadly i didnt have much luck with phase inversion.
Maybe i can track the tones somehow and then shift a notch compressor or something like that over the noise. So if for example there is a 300hz tone in track B, it will move the notch compressor to 300hz in track A. No idea how to track individual tones sady
i tryed as you said but the result was just silence, what am i doing wrong?
what will he be farmin
Thank you for that info it helped me a lot, i use Reaper and the side chain method worked :D
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may i ask what this is?