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SSTV images on microcassette?

PostPosted: Sun Dec 17, 2017 8:25 am
by OmegaProductions
Hello guys in NBTV!! :D
Today, I have a different topic about SSTV. How about recording SSTV signals onto a microcassette and playing them back on a SSTV app on the iPad? :idea:
It would have interesting results and the quality. Here are some photos of microcassette and of course, the compact-like recorder.
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In real life, I also found microcassette blanks still being sold at Maplin shop and the microcassette recorder in an antique shop in Leominster. I would want to have a try to record and playback signals from a microcassette. It would be interesting!! :) But anyways, that's all I have to say!! This is me Dylan signing out and goodbye!!!! :D :) :wink:

Re: SSTV images on microcassette?

PostPosted: Sun Dec 17, 2017 8:40 am
by Harry Dalek
Yes you can record sstv on tape the tape recorder player is some thing i used in the 1980's to record ham radio sstv there was still a little 8 second tests back then but mainly Martin 1, Scotty 1, Martin 2, Scotty 2 modes .

Re: SSTV images on microcassette?

PostPosted: Sun Dec 17, 2017 12:01 pm
by Steve Anderson
Interesting project. But be warned, these devices where mechanically poorly specified. The main application was dictation machines designed for speech only, but that bandwidth is enough for SSTV. Where they do fall down is speed regulation and wow-and-flutter, also consistency of speed between two machines. A tape recorded on one machine may sound fast or slow played back on another...to varying degrees.

If you're only going to use one machine then the speed issue should go away, but any wow-and-flutter will impose additional FM modulation on the SSTV sub-carrier...twice, once during record, once during playback.

Steve A.

Re: SSTV images on microcassette?

PostPosted: Mon Dec 18, 2017 12:50 am
by OmegaProductions
Steve Anderson wrote:Interesting project. But be warned, these devices where mechanically poorly specified. The main application was dictation machines designed for speech only, but that bandwidth is enough for SSTV. Where they do fall down is speed regulation and wow-and-flutter, also consistency of speed between two machines. A tape recorded on one machine may sound fast or slow played back on another...to varying degrees.

If you're only going to use one machine then the speed issue should go away, but any wow-and-flutter will impose additional FM modulation on the SSTV sub-carrier...twice, once during record, once during playback.

Steve A.

Yes! I noticed about that! I know most dictation machines sound poor, but I would want to have a try on it. I've seen some people record music on microcassette, but the audio sounds warped. Here is an example: https://www.youtube.com/watch?v=JFVmoHve6vw
But anyways, that's all I have to say! This is me Dylan signing out and goodbye!!!! :D :) :wink:

Re: SSTV images on microcassette?

PostPosted: Mon Dec 18, 2017 8:15 pm
by Steve Anderson
Yep, that's good old wow and flutter. Wow is the low-frequency modulation, a good example being a well off-centre record - the vynal sort. Flutter is caused by cheap or worn belts/pulleys/etc used to reduce the motor RPM. That video is a good example of quite severe flutter...such that I could only listen for the first minute or so! Pianos are a very stringent test for wow and flutter.

I wish you good luck!

Steve A.

Re: SSTV images on microcassette?

PostPosted: Tue Dec 19, 2017 4:20 am
by OmegaProductions
Oh yeah! :!: I know what wow and flutter us, but I didn't know that wow means *low-frequency* while flutter means *worn out belts*, now I know how wow and flutter really is! But anyways, I'll just keep this subject for the future, since I do not have a microcassette recorder and blank tapes yet, so that's all I have to say! Goodbye!!!! :D :) :wink:

Re: SSTV images on microcassette?

PostPosted: Tue Dec 19, 2017 11:21 am
by Steve Anderson
Yep, that's it. Another explanation is in the introduction here...

https://en.wikipedia.org/wiki/Wow_and_f ... easurement

Don't bother reading the rest unless really interested...

Steve A.

Re: SSTV images on microcassette?

PostPosted: Wed Dec 20, 2017 2:15 am
by OmegaProductions
I get it! It's just mostly to do with the randomness of speeds and quality with the machine and tape itself. :| :!:

Re: SSTV images on microcassette?

PostPosted: Mon Jan 08, 2018 4:58 am
by Lowtone
I mesured the bandwith, it is about 7kHz maximum, and some faint noise can be percieved burried in the hiss until 10kHz.
SSTV needs 3kHz.