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What will happen if i tune a VHS VCR's analog tuner to a DVB-T mux's frequency, record the signal on a VHS tape, then use the RF out of the VCR to replay the captured signal into a DVB-T receiver box's RF input? Can i "tune" into the replayed mux and view the transmitted channels? (similarly how a Teletext signal is accessible when playing back a recorded analog broadcast)

A DVB-T mux can have an overall bitrate of 20-25Mbit/s which is like 180MB/minute of data. A 4 hour VHS tape could hold 40GB worthwile of data if it's possible to encode data in the modulation of DVB-T. It's a wild idea but can't find anything about it online.

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  • \$\begingroup\$ What is the analog bandwidth of a mux? \$\endgroup\$ – pjc50 Aug 3 '16 at 15:56
  • \$\begingroup\$ Depending on the configuration: 6-8Mhz. \$\endgroup\$ – NagyI Aug 3 '16 at 21:10
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No, it won't work. A VHS recorder relies very heavily on specific characteristics of an NTSC (analog) signal, and processes the Y (luminance) and C (chrominance) signals quite a bit both before and after transferring them to the tape. Anything that doesn't match the characteristics of these signals very closely will be badly distorted if it gets recorded at all.

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According to Wikipedia, a VHS recorder only has a video bandwidth of about 3MHz, so the odds of decoding a DVB-T transmission from it are pretty slim. To make it worse, the helical scanning produces regular head switches during which any data would be corrupted. These are normally hidden in an analogue video signal by arranging that they are right at the bottom of the frame. This won't work for a continuous digital broadcast.

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