Post-war UK TV standards. - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 12th Jan 2006, 11:41 am

Hi everyone,
Some time ago I read somewhere that at the end of WW2 a committee was set up to discuss the future of television in the UK. Obviously, the question of transmission standards was in the discussion.
Cossor came up with a proposal of a 50Hz 525 line system, this would operate in the existing 3.5Mhz sound vision spacing. Max video was to be 3.1Mhz. The line frequency would be 13125Hz so most of the existing sets could just about manage to work OK
Has anyone read or heard about this?

DFWB.

ppppenguin · 12th Jan 2006, 11:47 am

New one to me. I thought the choice was between staying with 405 and moving to 625. In retrospect, we probably made the wrong choice though it certainly looked right at the time. If we'd moved to 625, it would have seriously delayed the restart of the service. Compensating no more than 20,000 pre-war set owners would have been a lesser problem.

FERNSEH · 12th Jan 2006, 12:03 pm

Didn't EMI propose a 605 line system? 11 X 11 X 5

Guess it seemed a good idea to stay with the pre-war standard for the post-war TV service. It would get us back into TV as cheaply as possible and It must be remembered the country was broke.

DFWB

Duke_Nukem · 12th Jan 2006, 12:21 pm

I've not seen anything on this but would be very interested if you do turn up anything.

If cossor made such compatability claims then I can't help feeling they were wrong - I think asking an existing set to make a 25% faster line scan without reducing the width could only be achieved with a 25% boost in HT.

Quote:

In retrospect, we probably made the wrong choice though it certainly looked right at the time.

Choosing 625 lines at that time would have increased the cost of new sets doing nothing to help promote television. Also many sets struggled to even use the full 405 quality, so that combined with the small screens meant there'd have been little point in moving to 625.

TTFN,
Jon

Hybrid tellies · 13th Jan 2006, 1:31 am

If the committee had chosen 625 with it's wider bandwidth it would have meant that the BBC would have needed both vhf tv bands (Bands 1 & 3) for it's national network as you can only squeeze in 3 625 line channels on band 1.
Sticking with 405 lines made it possible for a second national tv network (ITV) to start up in the 1950's using the band 3 channels.
I read somewhere that at one time they were considering using band 2 for television broadcasting before they decided to use this band for radio broadcasts.

12th Jan 2006, 11:41 am	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Post-war UK TV standards. Hi everyone, Some time ago I read somewhere that at the end of WW2 a committee was set up to discuss the future of television in the UK. Obviously, the question of transmission standards was in the discussion. Cossor came up with a proposal of a 50Hz 525 line system, this would operate in the existing 3.5Mhz sound vision spacing. Max video was to be 3.1Mhz. The line frequency would be 13125Hz so most of the existing sets could just about manage to work OK Has anyone read or heard about this? DFWB.

12th Jan 2006, 11:47 am	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Post-war UK TV standards. New one to me. I thought the choice was between staying with 405 and moving to 625. In retrospect, we probably made the wrong choice though it certainly looked right at the time. If we'd moved to 625, it would have seriously delayed the restart of the service. Compensating no more than 20,000 pre-war set owners would have been a lesser problem.

12th Jan 2006, 12:03 pm	#3
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Post-war UK TV standards. Didn't EMI propose a 605 line system? 11 X 11 X 5 Guess it seemed a good idea to stay with the pre-war standard for the post-war TV service. It would get us back into TV as cheaply as possible and It must be remembered the country was broke. DFWB

13th Jan 2006, 1:31 am	#5
Hybrid tellies Nonode Join Date: Jan 2004 Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area. Posts: 2,965	Re: Post-war UK TV standards. If the committee had chosen 625 with it's wider bandwidth it would have meant that the BBC would have needed both vhf tv bands (Bands 1 & 3) for it's national network as you can only squeeze in 3 625 line channels on band 1. Sticking with 405 lines made it possible for a second national tv network (ITV) to start up in the 1950's using the band 3 channels. I read somewhere that at one time they were considering using band 2 for television broadcasting before they decided to use this band for radio broadcasts. __________________ Simon BVWS member