Marlyn Robinson writes:

>According to the BBC website: 'There had been experimental transmissions 
>from a studio in Broadcasting House since 1932. On 2 November 1936 the BBC 
>opened the world's first regular service of high-definition television 
>from Alexandra Palace in North London...'

This is not strictly true.  The transmissions which began on 2 November 
1936 were also experimental.  For a three-month period starting then, the 
Baird 240-line mechanical system and the EMI 405-line cathode ray tube 
electronic system (technically similar to the Zworykin/RCA method but 
developed independently, though licensing some of Philo Farnsworth's 
patents) were broadcast on alternate days or weeks (can't remember which), 
in order for the BBC to evaluate which one to adopt for its regular 
broadcasting.  EMI was declared the winner and regular broadcasts were 
established for approximately two hours a day until the war broke out in 
September 1939.

Two relevant sources: Robert Alexander, 'Alan Dower Blumlein - The Man Who 
Invented Stereo' (Oxford, Focal Press, 1999) - Blumlein was an EMI engineer 
who, as well as inventing stereo audio recording and several key elements 
of radar technology, was also heavily involved in the design of the 
'Emitron' TV camera.  Also, Neil Robson, 'Living Pictures Out of Space: The 
Forlorn Hopes for Television in Pre-1939 London', Historical Journal of 
Film, Radio & Television, 24/2 (June 2004), pp. 223-32. 

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