29 Feb
2012
29 Feb
'12
2:40 a.m.
On 2012 Feb 28, at 10:43 PM, William Donzelli wrote:
I'm not having much luck finding examples of actual models, and I
don't know about RCA specifically, but TMU there were theatre or
large-screen projection TVs made with Kerr cells (for light
modulation) and rotating mirrors (scanning) for display of the
standard TV signal around that era. I thought Scott made a home TV of
this form (40s). As such, there were mechanical-scan systems aside
I don't
have examples, but to give him the benefit of the doubt,
perhaps he
was referring to special cases such as projection TVs or some-or-
other
studio equipment. Working in RCA he might have been seeing stuff
most people
wouldn't.
I have a LOT of 1950s tech docs on RCA television equipment, and I
have never seen any hybrid mechanical systems mentioned in them.
Perhaps he might be confusing the television for radar indicators. In
the mid 1950s, there were still some PPI scopes with the rasters
scanned mechanically, by rotating the yoke. This was a very common
method to get the rotating raster back in the 1940s, but started to be
replaced by all electronic sweep generators in the 1950s. The last use
I can think of for these rotating yokes was on the SAGE gap filler
nodes, made by Westinghouse - up to seven yokes on seven tubes
spinning in sync. from the very early (20s-30s) experimental systems and
the CBS
sequential-field colour system.