UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Heatercathodeshort · 23rd Feb 2011, 6:12 pm

The whole point of the electronic Marconi EMI system was that it was capable of outstanding results, mobile and instant! In the early days the Emitron cameras were rolled out onto the terrace at Alexandra Palace and live 'outside' broadcasts transmitted. This was followed in early 1937 with a completely independent outside broadcast unit mounted on an AEC lorry chassis. Absolutely incredible and years ahead of it's time. The results, given a good signal path to Highgate were excellent. All this was impossible to achieve with the ludicrous Baird I.F. system. He must have stood in the background during the electronic transmission weeks and realized there was no competition and the outcome would be obvious. The whole idea of television was that it was to be 'film less' and the processing and scanning although clever was nothing more than a contraption.
The 405 system was indeed incredible remaining little changed from it's 1936 concept and to continue it after the war was without doubt the right decision. It also gave our manufacturers a head start to post war production of receivers. If we had changed to a 625 CCIR system our industry would have gone under due to imports fifty years before it eventually did. It is also forgotten that we exported very large numbers of 625 line receivers during the 50's and 60's continuing into the 70's. I don't think a 625 line picture would have been any better if as good as 405. The picture tubes of the time would have had a problem focusing such a small spot size and any increased bandwidth would have been lost to the final viewer. 405 line pictures produced on 21" and 24" tubes are truly excellent given a reasonable viewing distance as can be seen by pictures produced on the Philips 21TG100U series and many others. 405 held it's head well above the rest for years beyond it's sell by date and is still making a pretty good show even today via the AURORA. It was also and most importantly loved by it's users. I was there and experienced it first hand. Regards, John.

23rd Feb 2011, 6:12 pm	#6
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: 240, 405 & 625 The whole point of the electronic Marconi EMI system was that it was capable of outstanding results, mobile and instant! In the early days the Emitron cameras were rolled out onto the terrace at Alexandra Palace and live 'outside' broadcasts transmitted. This was followed in early 1937 with a completely independent outside broadcast unit mounted on an AEC lorry chassis. Absolutely incredible and years ahead of it's time. The results, given a good signal path to Highgate were excellent. All this was impossible to achieve with the ludicrous Baird I.F. system. He must have stood in the background during the electronic transmission weeks and realized there was no competition and the outcome would be obvious. The whole idea of television was that it was to be 'film less' and the processing and scanning although clever was nothing more than a contraption. The 405 system was indeed incredible remaining little changed from it's 1936 concept and to continue it after the war was without doubt the right decision. It also gave our manufacturers a head start to post war production of receivers. If we had changed to a 625 CCIR system our industry would have gone under due to imports fifty years before it eventually did. It is also forgotten that we exported very large numbers of 625 line receivers during the 50's and 60's continuing into the 70's. I don't think a 625 line picture would have been any better if as good as 405. The picture tubes of the time would have had a problem focusing such a small spot size and any increased bandwidth would have been lost to the final viewer. 405 line pictures produced on 21" and 24" tubes are truly excellent given a reasonable viewing distance as can be seen by pictures produced on the Philips 21TG100U series and many others. 405 held it's head well above the rest for years beyond it's sell by date and is still making a pretty good show even today via the AURORA. It was also and most importantly loved by it's users. I was there and experienced it first hand. Regards, John.