[78-L] Grooved video discs 78rpm resp. 1500rpm (''mechanical TV'')

[David Breneman]

--- On Thu, 10/11/12, Benno Häupl <goldenbough at arcor.de> wrote:


> Scottish inventor John Logie Baird devolped a system using
> grooved discs 
> that could reproduce moving pictures of 30 lines. Has
> anybody here seen 
> (or own) a grooved video disc made according to this
> standard (around 1928)? 

As far as I know, this product never got beyond the
prototype phase.  There are only a few known to exist.