DATV TX Tutorial: Difference between revisions

Latest revision as of 22:18, 13 September 2026

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Software and example files[edit | edit source]

GNU Radio Companion. The original guide linked a Windows radioconda installer; use the radioconda project for current installers.
FFmpeg builds for preparing the video.
Mukhash2012's DVB-S2 flowgraph and SimTX preset. Keep both files together for reference.
A receiver setup from DATV RX Tutorial for checking the result.

1. Prepare the video[edit | edit source]

The original example converts an MP4 to an MPEG transport stream with low-rate H.264 video and mono AAC audio. Replace the input and output filenames with your own. This preserves the settings supplied by the original tutorial.

ffmpeg -i File_name.mp4 -c:v libx264 -b:v 85k -maxrate:v 85k -bufsize:v 30k -preset slow -profile:v baseline -level 3.0 -vf "scale=320:240,fps=12,format=yuv420p" -c:a aac -b:a 24k -ac 1 -f mpegts -muxrate 140k -mpegts_pmt_start_pid 0x1000 -mpegts_start_pid 0x0100 -pcr_period 20 -pat_period 0.1 File_name.ts

2. Configure GNU Radio and SimTX[edit | edit source]

Open the supplied .grc flowgraph in GNU Radio Companion.
Open its File Source block and select the converted .ts file. A File Source reads the video; a File Sink writes an output file.
Check the flowgraph's TCP Sink. In the illustrated setup it is a client connecting to 127.0.0.1, port 7355.
In SimTX, use Presets > Load Preset File... to load the supplied .stxpreset.
Review the preset's station, frequency, power, and antenna. Confirm GNU Radio IQ is selected, its IQ Port matches the TCP Sink, and the expected sample rate matches the flowgraph.

GNU Radio DVB-S2 flowgraph with File Source, coding blocks, filter, and TCP Sink to localhost port 7355. — The original flowgraph illustration. It shows a 200000 samples/s output, 100000 symbols/s, QPSK, and code rate 3/4. Current downloaded files should be checked rather than assumed identical.

3. Start and verify[edit | edit source]

Start the SimTX transmission first so its local IQ input is listening.
Run the GNU Radio flowgraph so the TCP Sink connects to it.
Use DATV RX Tutorial with matching DVB-S2 parameters to check reception.

The illustrated parameters are one example, not settings for every DATV station. If no picture appears, check TCP connectivity first, then sample rate, symbol rate, code rate, receiver frequency, and signal strength. Stop the SimTX session when the test is finished.

@@ Line 1: / Line 1: @@
-First you need to download [https://glare-sable.vercel.app/radioconda/radioconda-installer/radioconda-.*-Windows-x86_64.exe GNU Radio Companion]
+{{Documentation navigation}}
-And [https://github.com/btbn/ffmpeg-builds/releases ffmpeg]
+== Software and example files ==
+* GNU Radio Companion. The original guide linked a Windows radioconda installer; use the [https://github.com/ryanvolz/radioconda radioconda project] for current installers.
+* [https://github.com/btbn/ffmpeg-builds/releases FFmpeg builds] for preparing the video.
+* [https://github.com/Mukhash2012/DVB-S2-SimTX Mukhash2012's DVB-S2 flowgraph and SimTX preset]. Keep both files together for reference.
+* A receiver setup from [[DATV RX Tutorial]] for checking the result.
-And you need to download [https://github.com/Mukhash2012/DVB-S2-SimTX my (Mukhash's) GNU set and SimTX preset (recommended)][[File:RX1.png|500px|thumb|left|1.1 Welcome to SDRAngel!]]
+== 1. Prepare the video ==
-[[File:RX2.png|500px|thumb|left|1.2 Now add RX device]]
+The original example converts an MP4 to an MPEG transport stream with low-rate H.264 video and mono AAC audio. Replace the input and output filenames with your own. This preserves the settings supplied by the original tutorial.
-[[File:RX3.png|500px|thumb|left|1.3 Select RemoteTCPInput]]
-[[File:RX4.png|500px|thumb|left|1.4 Copy the settings as seen here.]]
+<syntaxhighlight lang="bash">
-[[File:RX5.png|500px|thumb|left|1.5 Add channel]]
+ffmpeg -i File_name.mp4 -c:v libx264 -b:v 85k -maxrate:v 85k -bufsize:v 30k -preset slow -profile:v baseline -level 3.0 -vf "scale=320:240,fps=12,format=yuv420p" -c:a aac -b:a 24k -ac 1 -f mpegts -muxrate 140k -mpegts_pmt_start_pid 0x1000 -mpegts_start_pid 0x0100 -pcr_period 20 -pat_period 0.1 File_name.ts
-[[File:RX6.png|500px|thumb|left|1.6 Select DATV Demodulator]]
+</syntaxhighlight>
-[[File:RX7.png|500px|thumb|left|1.7 Almost done with SDRAngel!]]
-[[File:RX8.png|500px|thumb|left|1.8 Copy the settings as seen there or configure it to the DATV Stations requirements]]
+== 2. Configure GNU Radio and SimTX ==
-[[File:RX9.png|500px|thumb|left|1.9 You can click it if you think that you are done now!]]
+# Open the supplied <code>.grc</code> flowgraph in GNU Radio Companion.
-[[File:RX21.png|500px|thumb|left|2.1 However you are not done if you want to watch and playback the DATV capture, click UDP button and configure the UDP option as seen here]]
+# Open its '''File Source''' block and select the converted <code>.ts</code> file. A File Source reads the video; a File Sink writes an output file.
-[[File:RX22.png|500px|thumb|left|2.2 Install [https://potplayer.tv/ Potplayer] (recommended tool)]]
+# Check the flowgraph's '''TCP Sink'''. In the illustrated setup it is a client connecting to <code>127.0.0.1</code>, port <code>7355</code>.
-[[File:RX23.png|500px|thumb|left|2.3 Click the playlist button]]
+# In SimTX, use '''Presets''' > '''Load Preset File...''' to load the supplied <code>.stxpreset</code>.
-[[File:RX24.png|500px|thumb|left|2.4 Playlist window will open, click ADD]]
+# Review the preset's station, frequency, power, and antenna. Confirm '''GNU Radio IQ''' is selected, its IQ Port matches the TCP Sink, and the expected sample rate matches the flowgraph.
-[[File:RX25.png|500px|thumb|left|2.5 Select Add URL]]
-[[File:RX26.png|500px|thumb|left|2.6 Paste "udp://127.0.0.1:8888" into there]]
+[[File:TX1.png|thumb|center|1000px|alt=GNU Radio DVB-S2 flowgraph with File Source, coding blocks, filter, and TCP Sink to localhost port 7355.|The original flowgraph illustration. It shows a 200000 samples/s output, 100000 symbols/s, QPSK, and code rate 3/4. Current downloaded files should be checked rather than assumed identical.]]
-[[File:RX27.png|500px|thumb|left|2.7 Finished! Now start both and enjoy!]]
+== 3. Start and verify ==
+# Start the SimTX transmission first so its local IQ input is listening.
+# Run the GNU Radio flowgraph so the TCP Sink connects to it.
+# Use [[DATV RX Tutorial]] with matching DVB-S2 parameters to check reception.
+The illustrated parameters are one example, not settings for every DATV station. If no picture appears, check TCP connectivity first, then sample rate, symbol rate, code rate, receiver frequency, and signal strength. Stop the SimTX session when the test is finished.
+[[Category:SimTX]]