Big screen 405 line TV set.

[Synchrodyne]

I don't know if there was an unintended consequence of protectionism in programme material. Optical conversion was always possible. I don't know if ORTF followed the BBC in devising electronic 819<> 625 conversion. In any case, there must have been practical solutions. I have a distinct memory of seeing an episode of the Forsyte Saga in Brussels on 819 lines. Date would have been the late 1960s. I don't know if this was on French or Belgian TV. Reception wasn't very good but I remember the line whistle as inaudible.

According to this map from Wireless World 1959 March, the European network had quite a few standards conversion points by then.

   

I imagine that these conversion points were used mainly for live transmissions, where loss of picture quality was probably an acceptable trade-off for immediacy.  In those days I think that programme exchange was mostly done with 16 mm film.  Certainly most of what came into New Zealand in the 1960s was on film.  I recall the original Forsyte saga series (With Eric Porter, Nyree Dawn Porter and with Susan Hampshire as a particularly dislikeable Fleur in the later episodes), and the picture quality was good.  Perhaps it was done originally with film rather than videotape.  Some of the programmes that came into NZ were obviously transfers from videotape originals.  In the case of American origin materials, image orthicon artefacts such as black fringing were often visible.  In the UK case, one Granada-origin programme attracted quite a bit of adverse public comment about its poor picture quality, and that was explained as being because it was a film transfer from an original 405-line videotape.  I guess that quite a bit of spot wobble was used to minimize visibility of the line structure, but the result was a vertically smeared look.  Sound quality in general was different between American and British programmes.  In the former case, there was some peak clipping but a lower noise floor.  In the latter there was less peak clipping but a higher noise floor.  But I digress.

Re the Belgian case, as I understand it, the use of 819-line system F was stopped in 1968, at which time the Wallonia network on VHF moved to 625-line system C (as used for the Flemish network), the whole VHF transmitter network having been installed with the capability of handling both systems.  I don’t know for sure, but I’d guess this was done once electronic standards conversion, particularly 819-to-625, was considered to be adequately economic, reliable and in particular of sufficient quality, picture-wise, to be used on a full-time basis,

The French 819 system must have suffered quite badly when videotape was introduced in 1956. Although 4 standard Quadruplex machiines were available (the Ampex VR2000 was 405/525/625/819)  I'm pretty sure that they couldn't achieve anything like good performance with 10mHz video BW.

That’s an interesting point that had not occurred to me before.  I wonder if that was one of the reasons that France decided to move to 625/50 for its second network.

Here is the French section extracted from the CCIR 1959 Los Angeles meeting, Report #123 “Television Standards for Bands IV and V”.  This largely came from a CCIR Study Group meeting held in Moscow in 1958, having been commissioned at the CCIR 1956 Warsaw meeting.

   

At that time France was still contemplating using 819/50 for a monochrome UHF network (using double 8 MHz channels), but 625/50 for a colour UHF network in the 8 MHz channel with 6.5 MHz intercarrier.  Clearly the 819/50 idea had been abandoned by the time of ITU ST61 (and its preceding Cannes meeting of experts).

Initial SECAM colour work with 819/50 had the subcarrier at 8.37 MHz.  Perhaps that was seen as just not doable with the videotape technology of the time, nor with any reasonably foreseeable improvements thereto.  Hence the “fallback” to 625/50, where the 4.43 MHz colour subcarrier was within the range of videotape technology.  Once 625/50 was in play for the colour case, out of necessity it would seem, it was not such a big step to abandoning the 819/50 at UHF idea.

Also, here is the UK submission from R123:

   

This shows that at the time, the UK was planning on a 625/50 system (if used) with 6 MHz vision bandwidth and 6.5 MHz intercarrier in the 8 MHz channel.


Cheers,

Steve