I'm planning on building my own Teletext service at some point as part of a wider analogue TV project. It's a cool form for things like the news because you have to be very concise for it to work in such a constrained format; it's the opposite of today where long-form content that doesn't really say anything is dirt cheap to emit at scale. Some of the British services had rudimentary games too like Bamboozle, a quiz game which relied on hexadecimal pages the remote couldn't enter manually.
One thing I'd also like to reinstate is NICAM digital stereo which British analogue TV used to have, most modulators I've come across only generate a mono FM subcarrier in PAL mode.
That brings back fond memories of my first employer in the early 90s.
They used to rent a single scan line (VBI) of the TV broadcast to use as a data transmission method encoded the same way Teletext was. IIRC you could fit 45 bytes in a single scan line, with 50 per second that gives you a nationwide data broadcast capability of something like 18 kbit/s. We had a 19,200 bits/second leased line to send the data.
That scan line was really really expensive I seem to remember! If your TV wasn't quite adjusted properly you could see the data scan lines at the top of the screen as flickering white dots and lines which was fun.
The data got sent to financial institutions for real time stock feeds and nationwide networks of shops.
I never worked on the code for that part of the business though - I worked on the replacement system which ran via satellite with much more bandwidth at much lower cost.
Imagine a meshtastic network of devices across a city or country, broadcasting a set of rotating teletext pages with no ability to censor it. That would be something.
> with no ability to censor it
Except, of course, policemen knocking on your door. Wouldn't be necessary anyways, most people would not even try broadcasting on the mere threat of arrest.
Please consider framing your project in your mind as a hobby.
It’s valuable to the degree that you enjoy it. Learning and other external values don’t have to apply here.
Just the fun of doing it can be enough.
This Teletext emulator displays a few projects recreating various services: https://zxnet.co.uk/teletext/viewer/.
I'm planning on building my own Teletext service at some point as part of a wider analogue TV project. It's a cool form for things like the news because you have to be very concise for it to work in such a constrained format; it's the opposite of today where long-form content that doesn't really say anything is dirt cheap to emit at scale. Some of the British services had rudimentary games too like Bamboozle, a quiz game which relied on hexadecimal pages the remote couldn't enter manually.
One thing I'd also like to reinstate is NICAM digital stereo which British analogue TV used to have, most modulators I've come across only generate a mono FM subcarrier in PAL mode.
That brings back fond memories of my first employer in the early 90s.
They used to rent a single scan line (VBI) of the TV broadcast to use as a data transmission method encoded the same way Teletext was. IIRC you could fit 45 bytes in a single scan line, with 50 per second that gives you a nationwide data broadcast capability of something like 18 kbit/s. We had a 19,200 bits/second leased line to send the data.
That scan line was really really expensive I seem to remember! If your TV wasn't quite adjusted properly you could see the data scan lines at the top of the screen as flickering white dots and lines which was fun.
The data got sent to financial institutions for real time stock feeds and nationwide networks of shops.
I never worked on the code for that part of the business though - I worked on the replacement system which ran via satellite with much more bandwidth at much lower cost.
Eventually the internet killed that too :-)
Imagine a meshtastic network of devices across a city or country, broadcasting a set of rotating teletext pages with no ability to censor it. That would be something.
The same author dabbled in a similar project, so maybe there's a tie-in possible?
https://spectrum.ieee.org/run-a-meshtastic-bbs
> with no ability to censor it Except, of course, policemen knocking on your door. Wouldn't be necessary anyways, most people would not even try broadcasting on the mere threat of arrest.
Please consider framing your project in your mind as a hobby. It’s valuable to the degree that you enjoy it. Learning and other external values don’t have to apply here. Just the fun of doing it can be enough.
I'm familiar with the author's past work on ieee.org and have a sense that he likes to write to/for both hobbyist and professional camps:
https://spectrum.ieee.org/u/stephen-cass
Ham radio as a whole is a great hobby to sink your random RF projects into already.. its a hobby within a hobby, no matter what path you may take ;)