NBTV Quickie

Forum for discussion of narrow-bandwidth mechanical television

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Re: NBTV Quickie

Postby Klaas Robers » Sat Apr 07, 2018 12:43 am

Nor will I. I think it too far, half a day travelling, to do that each year.

About SECAM: it is difficult to fade-in and -out a SECAM video signal. This can simply be done with a PAL signal as long as the sync and the (AM) subcarrier is synchronised. That is the reason that in France everything is working in PAL, exept the terrestrial transmission. And it pointed out that conversion PAL to SECAM and also SECAM to PAL is very simple.

East Germany DDR was using SECAM as well, but ALL TV-receivers could also receive PAL (there was a SECAM to PAL converter inside, so nobody observed any difference when the PAL to SECAM converters in the transmitters were removed ..... So in fact total Europe plus the UK was equiped with PAL.
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Re: NBTV Quickie

Postby Steve Anderson » Sat Apr 07, 2018 7:29 pm

Panrock wrote:This year, I understand all our gear is to be put through a PAT test before being allowed, so more luck needed! Steve O

*Groans* What more H&S bollocks? "Oh no, you can't bring a soldering iron in here, it generates temperatures in excess of 70 Celcius. If you do everyone has to wear PPE, hi-vis vests, steel-capped footwear and a hard-hat. In fact add to that ear-defenders for the high-velocity spinning discs and protective eye-wear."

Yet one more reason I'm glad I don't live in the UK anymore. Great to visit once in while, but that's it!

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Re: NBTV Quickie

Postby Harry Dalek » Sun Apr 08, 2018 9:52 am

Hope the NBTVA 2018 UK Convention gos ok this year today infact my time ..i didn't think of it at the time but you could set up a PC for the forum there and we who can't go could show something we have made but can't get there ! occupational health and safety nice and safe we don't have to travel ! :wink:
The electromagnetic spectrum has no theoretical limit at either end. If all the mass/energy in the Universe is considered a 'limit', then that would be the only real theoretical limit to the maximum frequency attainable.
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Re: NBTV Quickie

Postby grahamhunt » Sun Apr 08, 2018 11:53 pm

steves colour monitor was impressive as always. The conversion to horizontal scanning worked well as did the switchable frame rate a noticable differance in flicker apparant . Harry's suggestion of a virtual display for members unable to attend is a good idea not shore if there is a broad band signal at the venue that would allow it
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Re: NBTV Quickie

Postby Panrock » Mon Apr 09, 2018 12:53 am

Graham's display gave very good colour fidelity and in particular, impressive gradation in the subtle shadow areas of the picture. All housed in a period early '30s cabinet.

He said he had heard I was deceased and was therefore surprised to see me... I told him he was dealing with my ghost! :D

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Re: NBTV Quickie

Postby Dave Moll » Mon Apr 09, 2018 3:32 am

Harry Dalek wrote:i didn't think of it at the time but you could set up a PC for the forum [at the Convention] and we who can't go could show something we have made but can't get there ! occupational health and safety nice and safe we don't have to travel ! :wink:


Certainly something to be thought about for next time - assuming internet access is feasible there.
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Re: NBTV Quickie

Postby murphyv310 » Sat May 05, 2018 5:29 am

Panrock wrote:I'm sure no apology is needed, Dave. I'm only sorry our signal is unlikely to reach Cumbria! :-)

Thank you for the part you play in running this great Forum.

Steve O


Steve you never know how far that signal will go.
Once the frequency is known I'll be building a cubical quad and try.
I'm hoping good results whenever there is a lift.
Cheers Trevor.
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Re: NBTV Quickie

Postby Panrock » Tue May 08, 2018 12:12 am

Thanks Trevor. I have the feeling you could well be right. ;-)

Putting this transmitter together has become my full-time (unpaid!) job. I have the benefit of being able to call on expert help when I need it (often!). Some may wonder why it's taking so long but the fact is, this has turned into the biggest project I've ever been involved in.

We're taking every care with quality. The vision modulation will be properly clamped so that sync bottoms will be zero carrier under all conditions. This will look better on sets like the TV22, which tend to show flyback lines. The AM sound too should be excellent. Currently 1dB down at 16Hz and it's flat to well above the audio spectrum... I think we'll have to add some roll-off. I'm very excited about this project and look forward to the day we can release more details.

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Re: NBTV Quickie

Postby murphyv310 » Fri May 11, 2018 8:14 pm

Wow Steve.
Really pleased this is going forward so well. The AM sound should be terrific especially for the lucky ones close to the transmitter.
I wish you well with this but please don't take too many tea breaks :D :P :roll:
Cheers Trevor.
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