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Old 21st Dec 2017, 10:58 pm   #6
Pieter H
Tetrode
 
Join Date: Sep 2017
Location: Waalre, Netherlands
Posts: 67
Default Re: Philips tuners in UK sets

@ Synchrodyne, post #3
I think the reason for the IF changes in multi-norm sets was the following:
when there was only 4-norm VHF the picture IF was kept constant at 38,9, with the two sound IF's at 33,4 (CCIR-B and the two Belgian variants) and 27.75MHz (French 819lines VHF).
With the introduction of French UHF (6,5MHz picture-sound distance) it was easier to keep the sound IF's unchanged but change the picture IF (38,9 for CCIR-B and Belgium and French VHF) and 39,9 (for French UHF). This was integrally probably the easiest way, given that the sound IF's were narrow band and the video much more wide band. A bit of asymmetry on the Nyquist flank - which was probably the result of the rough IF bandwidth adaptation - was probably less of an issue than playing around with too many sound IF's.

And thanks for the AT6360 spec sheet, a nice addition. Interestingly, the UK tuners apparently introduced 4-section tuning already in valve tuners, where on the continent all valve UHF tuners remained 3-section, while 4-gang was only introduced with the transistor tuners (that will be described in pt3!).

@ Nick, post #4
So far I've only seen manufacturing of the tuners in Philips factories or affiliated ones, like CBRT in Belgium that was producing for Philips. Knowing Philips, which really started to make selling tuners a separate business starting around 1960, they would not license manufacturing but would try to sell tuners. Which was probably the case with Radio & Allied you describe. All other features you mention - wired control of the tuning axis, display - were all standard in the Philips sets (see the section in pt2 on UHF retrofit), and these concepts were probably sold with the tuner, like they were offered as internal retrofit sets.

@Fernseh, post #5
Thanks for the pictures!
The switch in picture 3 you refer to was officially the VHF-UHF switch, an integral part of the VHF tuner as described extensively. In UK sets this was of course equivalent to 405 (VHF) to 625 (UHF) switching.

Cheers, Pieter
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