System I and other TV standards - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 15th Oct 2007, 6:00 pm

Hi All,
The history of the UK 625 line system is very interesting. Why is it known as system I instead of something like system UK?

DFWB.

ppppenguin · 15th Oct 2007, 6:06 pm

All the systems have single letter designations. 405 is System A but that was named retrospectively. Many of the letters are missing from the sequence (there is no C or H for example). NTSC is M. With PAL-M in Brazil. B, G and I are closely related, so why the scatter of letters?

Mr Hoover · 15th Oct 2007, 8:07 pm

System C did exist,used in Belgium till 1978,same channels as system B but
with positive vision modulation and AM sound 5.5 MHz above the vision
carrier.Luxembourg I think also used it for a time.
System H is related to system B/G (these seem identical except G seems
to be the Uhf designation of system B) but has a 1.25MHz vestigal sideband.
This is all according to my 1985 World Radio TV Handbook!!
Who used system H I'm not sure.
Why the 525 system got put as far as M who knows

Some South American countries use system N (Argentina for one) which is
625 lines with American channel & 4.5 MHz vision sound spacing & PAL,this is
related to 50Hz mains frequency used there.

Hybrid tellies · 15th Oct 2007, 8:07 pm

I think some of the missing letters may well be the French 819 line system and its few variants which were found in some of the Benelux countries.
The current French 625 line system is Known as system L with its 6.5Mhz sound spacing and the use of AM+ vision modulation and AM sound modulation.
Systems D & K are the East European 625 line standards with 6.5Mhz sound spacing.
Its an interesting fact that the French were the only ones to stick with AM+ vision modulation together with AM sound as used on both our old 405 line system and their 819 line system.

ppppenguin · 15th Oct 2007, 8:12 pm

Quote:

Originally Posted by Hybrid tellies

I think some of the missing letters may well be the French 819 line system and its few variants which were found in some of the Benolux countries.

The 819 systems were E and F.

System A · 15th Oct 2007, 8:12 pm

Hi Fernseh
I'm not sure but System I was experimental in the Republic of Ireland first hence the letter "I". Is this correct?
Regards. Gary.

Hybrid tellies · 15th Oct 2007, 8:33 pm

The Irish switched to the 625 line system I using the vhf channels fairly early on in the 1960's but I don't think I stands for Ireland. I think it is just a designation given to this system by the likes of the EBU or whoever.

FERNSEH · 15th Oct 2007, 8:37 pm

Hi Gary,
You got it! A 625 line system with 6Mhz vision sound spacing was introduced into the Republic of Ireland in 1962 so it was only right the system was designated as I for Ireland.
Information about Irish TV can be found on Richard Logues excellent website.

http://www.irish-tv.com/hist60s.asp

DFWB.

Dave Moll · 15th Oct 2007, 8:45 pm

There is a fairly comprehensive list at Pembers' Ponderings.

arjoll · 15th Oct 2007, 8:46 pm

Quote:

Originally Posted by Mr Hoover

system B/G (these seem identical except G seems
to be the Uhf designation of system B)

They have a different channel spacing, but are otherwise identical. We use B/G here.

DrZarkov · 16th Oct 2007, 6:34 am

System H is in use in Germany. (And of course B, G.) The only difference to I is the distance of the sound carrier. I remember that I had to modify my TV in the eighties to receive BFBS TV (the british forces TV in our area, I live not far from Mönchengladbach).

arjoll · 16th Oct 2007, 6:55 am

Details of systems A to N are here.

Heatercathodeshort · 16th Oct 2007, 9:16 am

Quote:

Originally Posted by DrZarkov

System H is in use in Germany.

Named after a very unpopular guy that hung around in the 1930's and 40's maybe?.........J.

DrZarkov · 17th Oct 2007, 8:03 am

I don't think so. System H came in the 50th. The obsolete system from that period with 441 lines has no name, as I know. It should have been B, but B is used for the first "Gerber-norm" with 625 lines. The french used the old German system with 441 lines for a while after 1945. Maybe it has an official letter?

BTW: That guy with that ugly moustache had been nearly killed by TV: In 1938 he visited a public demonstration of TV. A few seconds after he had left the room, the CRT imploded.

That's what Wikipedia knows about the CCIR-letters:

Code lines framerate sound/picture-distance coloursubcarrier channelwidth picturesignal modulation band
(Hz) (MHz) (MHz) (MHz) (MHz) (MHz) Bild Ton
A 1 405 25 −3,50 2,66 5,00 3,0 0,75 positiv AM VHF
B 625 25 +5,50 4,43 7,00 5,0 0,75 negativ FM VHF
C 625 25 +5,50 4,43 7,00 5,0 0,75 positiv AM VHF
D 625 25 +6,50 4,43 8,00 6,0 0,75 negativ FM VHF
E 2 819 25 +11,15 8,37 14,00 10,0 2,00 positiv AM VHF
F 3 819 25 +5,50 ./. 7,00 5,0 0,75 positiv AM VHF
G 625 25 +5,50 4,43 8,00 5,0 0,75 negativ FM UHF
H 625 25 +5,50 4,43 8,00 5,0 1,25 negativ FM UHF
I 625 25 +6,00 4,43 8,00 5,5 1,25 negativ FM UHF
K 625 25 +6,50 4,43 8,00 6,0 0,75 negativ FM UHF
K'(K1) 625 25 +6,50 4,43 8,00 6,0 1,25 negativ FM UHF
L 625 25 +6,50 4,43 8,00 6,0 1,25 positiv AM UHF
M 4 525 30 +4,50 3,58 6,00 4,2 0,75 negativ FM UHF/VHF
N 625 25 +4,50 3,58 6,00 4,2 0,75 negativ FM UHF/VHF

Focus Diode · 18th Oct 2007, 5:46 am

Worth mentioning that System I is also used in Hong Kong (who also had 405 at least until 1972) and in South Africa.

I always assumed "I" was so named after Ireland although that could of course have been coincidental.

Brian

15th Oct 2007, 6:00 pm	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	System I and other TV standards Hi All, The history of the UK 625 line system is very interesting. Why is it known as system I instead of something like system UK? DFWB.

15th Oct 2007, 6:06 pm	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: System I? All the systems have single letter designations. 405 is System A but that was named retrospectively. Many of the letters are missing from the sequence (there is no C or H for example). NTSC is M. With PAL-M in Brazil. B, G and I are closely related, so why the scatter of letters?

15th Oct 2007, 8:07 pm	#3
Mr Hoover Hexode Join Date: Jan 2007 Location: Faro, Portugal Posts: 269	Re: System I? System C did exist,used in Belgium till 1978,same channels as system B but with positive vision modulation and AM sound 5.5 MHz above the vision carrier.Luxembourg I think also used it for a time. System H is related to system B/G (these seem identical except G seems to be the Uhf designation of system B) but has a 1.25MHz vestigal sideband. This is all according to my 1985 World Radio TV Handbook!! Who used system H I'm not sure. Why the 525 system got put as far as M who knows Some South American countries use system N (Argentina for one) which is 625 lines with American channel & 4.5 MHz vision sound spacing & PAL,this is related to 50Hz mains frequency used there.

15th Oct 2007, 8:07 pm	#4
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: System I? I think some of the missing letters may well be the French 819 line system and its few variants which were found in some of the Benelux countries. The current French 625 line system is Known as system L with its 6.5Mhz sound spacing and the use of AM+ vision modulation and AM sound modulation. Systems D & K are the East European 625 line standards with 6.5Mhz sound spacing. Its an interesting fact that the French were the only ones to stick with AM+ vision modulation together with AM sound as used on both our old 405 line system and their 819 line system. __________________ Simon BVWS member

15th Oct 2007, 8:12 pm	#6
System A Pentode Join Date: Feb 2006 Location: County Durham, UK. Posts: 234	Re: System I? Hi Fernseh I'm not sure but System I was experimental in the Republic of Ireland first hence the letter "I". Is this correct? Regards. Gary.

15th Oct 2007, 8:33 pm	#7
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: System I? The Irish switched to the 625 line system I using the vhf channels fairly early on in the 1960's but I don't think I stands for Ireland. I think it is just a designation given to this system by the likes of the EBU or whoever. __________________ Simon BVWS member

15th Oct 2007, 8:37 pm	#8
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: System I? Hi Gary, You got it! A 625 line system with 6Mhz vision sound spacing was introduced into the Republic of Ireland in 1962 so it was only right the system was designated as I for Ireland. Information about Irish TV can be found on Richard Logues excellent website. http://www.irish-tv.com/hist60s.asp DFWB.

15th Oct 2007, 8:45 pm	#9
Dave Moll Dekatron Join Date: Feb 2005 Location: West Cumbria (CA13), UK Posts: 6,127	Re: System I? There is a fairly comprehensive list at Pembers' Ponderings. __________________ Mending is better than Ending (cf Brave New World by Aldous Huxley)

16th Oct 2007, 6:34 am	#11
DrZarkov Retired Dormant Member Join Date: Jun 2007 Location: Herongen, Germany Posts: 65	Re: System I? System H is in use in Germany. (And of course B, G.) The only difference to I is the distance of the sound carrier. I remember that I had to modify my TV in the eighties to receive BFBS TV (the british forces TV in our area, I live not far from Mönchengladbach).

16th Oct 2007, 6:55 am	#12
arjoll Dekatron Join Date: May 2006 Location: Invercargill, New Zealand Posts: 3,457	Re: System I? Details of systems A to N are here.

17th Oct 2007, 8:03 am	#14
DrZarkov Retired Dormant Member Join Date: Jun 2007 Location: Herongen, Germany Posts: 65	Re: System I? I don't think so. System H came in the 50th. The obsolete system from that period with 441 lines has no name, as I know. It should have been B, but B is used for the first "Gerber-norm" with 625 lines. The french used the old German system with 441 lines for a while after 1945. Maybe it has an official letter? BTW: That guy with that ugly moustache had been nearly killed by TV: In 1938 he visited a public demonstration of TV. A few seconds after he had left the room, the CRT imploded. That's what Wikipedia knows about the CCIR-letters: Code lines framerate sound/picture-distance coloursubcarrier channelwidth picturesignal modulation band (Hz) (MHz) (MHz) (MHz) (MHz) (MHz) Bild Ton A 1 405 25 −3,50 2,66 5,00 3,0 0,75 positiv AM VHF B 625 25 +5,50 4,43 7,00 5,0 0,75 negativ FM VHF C 625 25 +5,50 4,43 7,00 5,0 0,75 positiv AM VHF D 625 25 +6,50 4,43 8,00 6,0 0,75 negativ FM VHF E 2 819 25 +11,15 8,37 14,00 10,0 2,00 positiv AM VHF F 3 819 25 +5,50 ./. 7,00 5,0 0,75 positiv AM VHF G 625 25 +5,50 4,43 8,00 5,0 0,75 negativ FM UHF H 625 25 +5,50 4,43 8,00 5,0 1,25 negativ FM UHF I 625 25 +6,00 4,43 8,00 5,5 1,25 negativ FM UHF K 625 25 +6,50 4,43 8,00 6,0 0,75 negativ FM UHF K'(K1) 625 25 +6,50 4,43 8,00 6,0 1,25 negativ FM UHF L 625 25 +6,50 4,43 8,00 6,0 1,25 positiv AM UHF M 4 525 30 +4,50 3,58 6,00 4,2 0,75 negativ FM UHF/VHF N 625 25 +4,50 3,58 6,00 4,2 0,75 negativ FM UHF/VHF Last edited by DrZarkov; 17th Oct 2007 at 8:09 am.

18th Oct 2007, 5:46 am	#15
Focus Diode Octode Join Date: Jan 2006 Location: Borough of Gateshead, UK. Posts: 1,420	Re: System I? Worth mentioning that System I is also used in Hong Kong (who also had 405 at least until 1972) and in South Africa. I always assumed "I" was so named after Ireland although that could of course have been coincidental. Brian