Viewing a VHS tape using RTL-SDR and TV Sharp software


Here’s a different and unconventional way to view a VHS tape (as if VHS tapes aren’t considered unusual enough today). DogsRNiceMineCraft posted this video on YouTube showing video received using an RTL-SDR dongle.

I got a VCR today and wanted to see if I could receive the signal from the RF out using TV sharp. I wrapped the antenna cord that came with my dongle around the RF out cable from the VCR, but it only works if the cable is barely touching the RF out port.

An unusual proof of concept which could have other applications.

The TV Sharp program referred to by the video’s poster appears to be available for download from radioamatoripeligni.it (Note: website primary language is Italian.) It allows reception of certain analog video signals using the RTL-SDR.

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4 Comments

  1. Perhaps someone should tell the guy back in the day you were supposed to CONNECT the RF-out to your antenna-in, not try to play SETI with it and see if you can pick it up with a coat-hanger wire or the Arecibo dish (or, indeed, with a piece of hardware specifically designed to pick up – *gasp* – RF TV broadcasts, a.k.a. TV tuner stick tunes in TV)…

    1. The RTL-SDR dongles aren’t designed to pick up analogue TV broadcasts so no, this isn’t a piece of hardware specifically designed to pick up RF TV broadcasts. They’re designed to receive DVB broadcasts with internal decoding. The SDR portion is exploiting the FM radio mode where it just acts like a ADC and streams the samples to the host for decoding.

  2. A more interesting hack might be to directly sample the output of the video heads and skip the VCR’s processing circuity. Then use DSP tricks to recover the best possible video off old, degraded tapes (starting with a software-based TBC). Maybe even take control of the rotation speed of the head (with a uC) and double (or more) the speed to get multiple samples of the same scan line – perhaps then being able to compensate for alignment/tracking issues that occur when reading a tape recorded on a different deck. I forget what the SNR of VHS tapes are — I wonder if it’s small enough for the RTL-SDR’s 8-bit ADC?

    1. That’s something i’m thinking about since i’ve discovered SDR: SDVTP = Software Defined Video Tape Player. Could be great to read and restore different types of old video tapes without the need of a complete working VTR. Or the same concept could be used also for any kind of magnetic tape or disc, like old computer tapes, floppy disks or hard drives.

      As you said, you would only need to have the mecanical part and a servo controlling system (original or homemade), and you could get rid of all other components (demodulator, TBC, …) and replace them by software modules, and possibly implement advanced treatment filters to get better video from poor tapes, where old electronics boards more or less fail. You could also have an universal NTSC/PAL/SECAM player, and maybe even analog/digital compatibility (Hi-8/Video-8/Digital/8, VHS/S-VHS/D-VHS, Betacam SP/Digital/SX/IMX…)
      I would dream to try to develop such a thing, but i’m afraid i’m lacking the knowledge (and time)… But if someday, somebody, somewhere starts to work on that, i would happily try to contribute! Anybody?

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