Wiki/Replay observations from audio - Revision history

Nye.thompson: Removed broken link

2023-02-05T13:19:44Z

Removed broken link

Nye.thompson at 13:11, 5 February 2023

2023-02-05T13:11:50Z

Knegge at 18:25, 26 October 2022

2022-10-26T18:25:47Z

Kerel+satnogs: Create page

2022-10-26T11:04:05Z

Create page

New page

{{Message|This page is under construction.}}

using the ogg audio from bpsk obs to replay and tune around the recorded band

@@ Line 10: / Line 10: @@
 ==Converting back audio to IQ==
-'''[[Automated back audio to IQ conversion|<big>An .exe file is available to automate this process >></big>]]'''
+'''<big>An .exe file is now available to automate this process. See 'Automated back audio to IQ conversion' below</big>'''
 Using our favorite SDR tools like [https://gqrx.dk/ gqrx], [https://www.sdrpp.org/ SDR++] etc will make it very easy to tune around and choose different modes, width etc, but they usually don't support this plain audio format.
@@ Line 40: / Line 40: @@
 [[File:Gqrx funcube bpsk.png]]
-== Automated back audio to IQ conversion ==
+==Automated back audio to IQ conversion==
 You can automate the process described above using this package: [https://drive.google.com/file/d/1lnl4AnKG-jt8-0e2C1I39b-Mf4OtqpyK/view?usp=share_link wav2iq_wav.7z]
-=== Installation ===
+===Installation===
-* Download the 7zip package to your Downloads directory.
+*Download the 7zip package to your Downloads directory.
-* Decompress the wav2iq_wav.7z to the current directory, it will create wav2iq_wav directory with the files inside of it.
+*Decompress the wav2iq_wav.7z to the current directory, it will create wav2iq_wav directory with the files inside of it.
-* Open the directory and scroll down to the bottom, there you will find wav2iq_wav.exe
+*Open the directory and scroll down to the bottom, there you will find wav2iq_wav.exe
-* Right-click and select copy, then on the desktop right-click and select Paste shortcut, you can then rename the shortcut if you like
+*Right-click and select copy, then on the desktop right-click and select Paste shortcut, you can then rename the shortcut if you like
-=== Conversion ===
+===Conversion===
 Select a SatNOGS observation that is recorded with the bpsk mode (perhaps others in the future) and download the audio ogg file. When it has completed, drag-and-drop it to the previously created shortcut. It will take some time and a black window should open for a short while and then disappear. This should have created a new file in the same directory. It will be named like the satnogs_xxxx.ogg but with the extension .iq.wav
@@ Line 58: / Line 58: @@
 [[File:Audacity.png|1000x1000px]]<br />
-=== Usage ===
+===Usage===
 The new file can be opened in SDR++ under Source, File: ... to open.

@@ Line 9: / Line 9: @@
 ==Converting back audio to IQ==
 Using our favorite SDR tools like [https://gqrx.dk/ gqrx], [https://www.sdrpp.org/ SDR++] etc will make it very easy to tune around and choose different modes, width etc, but they usually don't support this plain audio format.
@@ Line 37: / Line 39: @@
 [[File:Gqrx funcube bpsk.png]]
-{{Message|WIP WIP WIP}}
+<br />{{Message|WIP WIP WIP}}

← Older revision		Revision as of 18:25, 26 October 2022
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	{{Message\|This page is under construction.}}		{{Message\|This page is under construction.}}

−	~~using~~ the ~~ogg audio~~ from ~~bpsk obs~~ to ~~replay~~ and tune around the ~~recorded band~~	+	==Background==
		+	Running a SatNOGS station enables you to save the IQ files and look at the observation with other tools, these are not available for download from the usual [https://network.satnogs.org/observations/ Observations] page. Some do publish these on their own cloud storage or available by request. The possibility to get these are quite limited on the vast majority of the stations.
		+
		+	The Audio files are usually quite narrow and the mode selected changes it's behavior, it can be hard to use it for signals wider/higher/lower than what the original mode has requested.
		+
		+	One of the modes that has some opportunities is the BPSK flowgraph. Downloading one of these audio files will grant you a decent slice of the spectrum offset to 12kHz up (if baud was higher than 1200), this opens up for further processing, but how to do it ?
		+
		+	==Converting back audio to IQ==
		+
		+	Using our favorite SDR tools like [https://gqrx.dk/ gqrx], [https://www.sdrpp.org/ SDR++] etc will make it very easy to tune around and choose different modes, width etc, but they usually don't support this plain audio format.
		+
		+	Two methods have been tested successfully, both convert the audio file to a format these programs can use. This example uses [https://www.gnuradio.org/ gnuradio]-3.10, but 3.9 should also work just fine, 3.8 doesn't have OGG file support so you will have to convert it to WAV first.
		+
		+	Getting started in windows is usually a challenge for these tools so that is what this guide will address specifically, the package I used is [https://github.com/ryanvolz/radioconda/releases radioconda] and it includes gqrx and [https://gr-satellites.readthedocs.io/ gr-satellites] as well.
		+
		+
		+	Lets start with the flowgraph itself, available for download [https://github.com/kng/satnogs_gr-satellites/tree/main/utils here] as wav2iq_raw.grc.
		+
		+	[[File:Wav2iq raw.png]]
		+
		+	Open the Wav File Source and browse to the ogg/wav you want to convert, then open File Sink and select the destination raw (you can copy the string from the wav source and just change the extension to .raw). Then simply run the flowgraph with the play button or F6. It should only take a few seconds to complete as indicated by a >>> Done.
		+
		+	In this example I'm going to use observation [https://network.satnogs.org/observations/6659851/ #6659851]. This has a audio file size of about 10MB and the resulting raw is almost 130MB, so one can understand why this is not uploaded to the network.
		+
		+	==Opening RAW in gqrx==
		+
		+	Opening this file in gqrx is perhaps a bit cumbersome, but the dialog that appears on start is the Configure I/O devices, in this you will fill in a string formatted in this way:
		+	<br>file=C:/exmple/satnogs_6659851_2022-10-26T04-12-41.raw,rate=24e3
		+
		+	Note that the backslash is changed to forwardslash, and the rate at the end is the sample rate of the raw, in this case 24000 sps.
		+
		+	[[File:Gqrx configure iodev.png]]
		+
		+	After it's opened you can go ahead and select the mode and frequency etc.
		+
		+	[[File:Gqrx funcube bpsk.png]]
		+
		+
		+	{{Message\|WIP WIP WIP}}