NBTV Quickie

Forum for discussion of narrow-bandwidth mechanical television

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Re: NBTV Quickie

Postby Panrock » Tue Mar 13, 2018 6:02 pm

When colour started in the UK in 1967, there seemed to be a tendency by the BBC to avoid saturated pictures, or maybe I'm just remembering how my Dad always set it. Colour was only available on BBC2, which was their 'highbrow' channel.

At the time, we had a dual standard (405/625) 25-inch Baird on rental. After it was delivered, as soon as Dad was out of sight, I had the back off! He wouldn't have been best pleased...

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Re: NBTV Quickie

Postby Harry Dalek » Tue Mar 13, 2018 7:03 pm

Panrock wrote:When colour started in the UK in 1967, there seemed to be a tendency by the BBC to avoid saturated pictures, or maybe I'm just remembering how my Dad always set it. Colour was only available on BBC2, which was their 'highbrow' channel.

At the time, we had a dual standard (405/625) 25-inch Baird on rental. After it was delivered, as soon as Dad was out of sight, I had the back off! He wouldn't have been best pleased...

Steve O


OH so there was only a one channel colour start over there ,i do recall they all went colour but only some programs at a start .
We were renting a B/w tV at the time colour started i Questioned nagged Dad when are we going to get a colour tv he's answer was when this one brakes ...me thinking this could be years away ! So naughty little bugger i was found a screwdriver opened the back of the set found the power transformer stuck it in the transformers winding's and broke some them .....it was covered in wax so just had to replace some over the area ....no one will ever know ...!
It worked the set was stuffed no one found out and we got a colour set after a few days a small price to pay for colour tv !
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Re: NBTV Quickie

Postby Dave Moll » Tue Mar 13, 2018 7:53 pm

Yes, until the introduction of BBC, both of the existing channels (BBC - renamed BBC1, and ITV) were on 405 lines. Although experiments were carried out in the 1950s to broadcast in colour on 405 lines, this was never rolled out to the public, so all UK colour transmissions were on 625 lines. Panrock may correct me here, but I don't think BBC1 and ITV started 625-line transmissions until 1969. See his British Heritage Television web site for more detailed information on the timeline of television in the UK.
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Re: NBTV Quickie

Postby Klaas Robers » Tue Mar 13, 2018 8:20 pm

As far as I know, in the beginning of colour TV in the UK, all studios were already converted to 625 lines PAL colour. For the 405 line BBC-1 transmissions this 625 line signal was electronically converted to 405 lines by a tube-capacitor frame translator. It was a monster of a thing, but it worked! And it gave better pictures than the image-orthicon 405 line cameras. The BBC then worked with PAL 3-tube plumbicon cameras. At Philips research we had very close contacts with the BBC, as they were very critical at picture quality. That might also have been the reason behind the low saturation of the BBC images. When you know the scene, and there is not much saturation in the scene, then the transmitted signal also contains not much saturation. Besides that the picture in 405 line B/W should also be nice to view.
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Re: NBTV Quickie

Postby Panrock » Tue Mar 13, 2018 9:36 pm

Dave Moll wrote:See his British Heritage Television web site for more detailed information on the timeline of television in the UK.

Thanks for the plug Dave, but the web site and the (excellent) timeline there are not my work. I don't have such knowledge. Martin Allen is our historian - and Chairman. I'm just the general dogsbody putting together our new 405-line transmitter in the workshop. This is now my 'day job', though I took a week off lately for the 'NBTV Quickie'.

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Re: NBTV Quickie

Postby Dave Moll » Wed Mar 14, 2018 6:54 pm

My apologies to Martin for not giving him the credit due.
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Re: NBTV Quickie

Postby Panrock » Wed Mar 14, 2018 9:30 pm

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.

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Re: NBTV Quickie

Postby Lowtone » Wed Mar 28, 2018 5:05 am

Klaas Robers wrote: For the 405 line BBC-1 transmissions this 625 line signal was electronically converted to 405 lines by a tube-capacitor frame translator. It was a monster of a thing, but it worked!

See the difference of culture, and how to handle things.
In France, colour started in 1967 on channel 2 and 1972 on channel 3 of ORTF.
The first channel was still in black and white and 819 line standard. This was later renamed TF1.
The colourisation process started in late 1975 until 1983.

First they started to use the unused time on FR3. There was a testcard all day long and programs started in the evening.
So during the day TF1 was aired on FR3 in full SÉCAM colours. ( At that point FR3 was not covering all the country ).
The only program still produced in 819 line black and white was the news reports, especially for studio.

And it was converted… «electronically» but the french way.
They used a 625 line monochrome monitor and pointed a 819 line camera to it… :roll:

Later, everything was in colour but the stock exchange report. They used the same screen to camera method, and they somtimes applied a colour filter onto the signal.

But, they also had to do this to each transmitter in the country.
In parallel they built a 4th network for TF1 in colour and 625 line.

In the early 80's most people forgot about the 819 line channel, and it was discarted.
Transmitters were adapted to 625 line colour and we got the 4th channel CANAL+ in 1984.
That's why it was in VHF and not UHF.

( today we still find VHF antennas pointing to old ORTF or CANAL+ transmitters that doesn't exists anymore )

But this is my point, the british built a 405 line amazing converter, and the french just didn't bother and pointed a camera at a screen :lol:
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Re: NBTV Quickie

Postby Klaas Robers » Thu Apr 05, 2018 4:06 am

Oh yes, SECAM..... Very few people know that iin France:
- all TV cameras are in PAL,
- all TV studios are in PAL,
- all professional recording is done in PAL,
- the total distribution (micro wave links) is done in PAL
- all transmitters have a PAL to SECAM converter for the signal they transmit.

An then,
- all TVs have a built in SECAM to PAL converter before the colour signals are decoded.
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Re: NBTV Quickie

Postby Andrew Davie » Thu Apr 05, 2018 6:32 pm

Klaas Robers wrote:Oh yes, SECAM..... Very few people know that iin France:
- all TV cameras are in PAL,
- all TV studios are in PAL,
- all professional recording is done in PAL,
- the total distribution (micro wave links) is done in PAL
- all transmitters have a PAL to SECAM converter for the signal they transmit.

An then,
- all TVs have a built in SECAM to PAL converter before the colour signals are decoded.


That sounds stupid and bloody-minded!
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Re: NBTV Quickie

Postby Steve Anderson » Thu Apr 05, 2018 9:10 pm

Yep, Klaas is correct. I helped build a number of TV facilities in France, mostly in Paris, all were PAL. (Pre 1990's here). At the transmitter site there was a 1RU 19" box that converted the signal from PAL to SECAM. The rather unusual fact is that the majority of the converters were made by a UK company, Cox Electronics in Andover, Hants.

SECAM was a good transmission format but a right pain in the studio and post-production facilities.

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Re: NBTV Quickie

Postby Panrock » Fri Apr 06, 2018 5:09 am

Interesting about PAl-to-SECAM. I didn't know that.

Back to RGB... I now don't think that was 'overshoot' in the piano pic. It was an intentional reflection of the keyboard in the cartoon. Testament to Steve A's skill at designing the aperture corrector!

Had the rig running this evening to check it's ready for the Convention. It didn't like light from the window getting in the back... degraded the sync. Otherwise OK. Anybody from here coming on Saturday? Klaas perhaps? Dave Moll? AncientBrit ? :)

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Re: NBTV Quickie

Postby Harry Dalek » Fri Apr 06, 2018 8:33 am

I hope the gear and displaying does go well there Steve, i suppose things do go wrong at times at these events but i will will be wishing you luck and others at this event .
You should of missed this one remember your back from the dead ! :shock:
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Re: NBTV Quickie

Postby Panrock » Fri Apr 06, 2018 3:46 pm

Harry, thanks for the wishes. But would I have still gone as the "Ghost of NBTV"? :mrgreen:

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

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Re: NBTV Quickie

Postby Dave Moll » Fri Apr 06, 2018 5:03 pm

Panrock wrote:Anybody from here coming on Saturday? Klaas perhaps? Dave Moll? AncientBrit ? :)


Regrettably, I shan't be making it to the convention this time.
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