23 Apr
2006
23 Apr
'06
2:14 a.m.
From: "woodelf" <bfranchuk at jetnet.ab.ca>
Yes, I need to update that page - when I wrote it I didn't fully understand
the Jefferies cell.
I have recently acquired a number of early 30's "Television and Shortwave
Review" magazines (1934 to 1939), which have a lot of articles about the
Scophony system, which I need to scan and add to the page.
Jim Beacon wrote:
> I have a high speed scanner from a 405 line mechanical scan TV, from
around
1938:
www.g1jbg.co.uk/tv1.htm
Not computer related, but interesting in its own right.
But a little off with the
discription of the way the light was
modulated. This was a great invention but limited only to B&W
scanning. Similar to a mercury delay line for digital data,
this passed a entire scan line so that you got a full intensity
scan line to be sent to rotating mirrors then to the projection
screen. Alas WWII killed the company, and everybody by then
with CRT's improved do to WWII has continued using them to this day.
The rapid need for RADAR progress pushed CRT technology on at a fantastic
rate, such that the need for mechanical scan and high intensity light source
was replaced by the daylight-view CRT by the end of the war, and projection
CRTs were available (Skiatron?), reliable projection TV sets made there
appearance in the UK shortly after WW2 (using a 2.5" tube with a 25KV EHT,
and a very clever optical unit).
Jim.