Hi Synchrodyne,
another major piece of analysis, thanks!
I'm not going to respond to every individual paragraph, also because I agree with most of your analysis. So only a few items:
This is what
I wrote on the Belgian VHF standards:
To complicate matters further Vlaanderen (Flanders, the Dutch-speaking part of Belgium) defined their 625-line system as a compromise with the French 819-line standard, so AM sound and positive modulation, whereas Wallonie, the French-speaking part of Belgium as well as Luxembourg, opted for the 819-line system but squeezed into the 7MHz channel.
So in the end this was a typical Belgian compromise:
- There was some Flemish-Wallonie unity (channel width @ 7MHz, 5,5MHz Snd AM)
- But apart from that the Flemish system could be seen as a CCIR-B version.
- And the Wallonie system as a 819-line version.
Everybody happy, although at the expense of two more standards.
As to Italy, please note that they indeed conceptually took over the US NTSC IF and VHF-I channel arrangement,
but slightly modified:
- IF was 45,9MHz, not the NTSC-M 45,75MHz
- channel spacing was 7MHz, not the 6MHz NTSC
In my overviews there is not a single Philips Italian tuner with 45,75MHz, they are all 45,9, moving to 45,9/38,9 combos and ultimately 38,9 (when they were no longer special Italian tuners).
As to the UK 39,5 VIF, it was suggested to me by David Norton that the system-I N+1 sound IF trap would be the same as the sound carrier of VHF 405-line channel1. Which is correct!
- System-I (UHF only) channel 8Mhz, Vision-Sound distance 6MHz, so N+1 sound IF 2MHz above VIF = 39,5+2=41,5MHz
- System-A (VHF-only) Channel1 Vision 45MHz, sound 41,5MHz
Seems like a very plausible explanation, where if I'm correct Ch1 was the Crystal Palace transmitter from 1957 for the greater London area. Apparently this was a serious interference issue, especially with the first transistor tuners and their sensitivity to crosstalk. Moving the IF upwards in order to put the N+1 SIF trap exactly on 41,5MHz improved this issue.
In this context it is interesting to note how quickly the conversion - at least at set level - happened from 405 to 625 lines: only the 1966 G6 first colour TV and the 210 B&W chassis used a multi-mode IF, with 34,65/38,15MHz IF for the 405-line system, and the 39,5/33,5MHz for the 625-lines. See the IF curves below:
From 1970 all Philips sets were in principle UHF-only!
Cheers, Pieter