I think there's a research opportunity for someone that can dig through the original DuMont Laboratories papers in the Library of Congress on the "Duscopic" television prototypes.
I think the Duoscopic tv was originally developed for another purpose: 3D television.
The photo (above) shows someone in uniform sitting in front of a monitor and the monitor clearly shows two "side by side" 3D images, a format commonly used for printed 3D materials in scientific and military work for many years. (The images could be viewed in 3D by crossing one's eyes or using an cardboard viewer placed over the two images.)
The dating of the Duoscopic tv is curious - "Bwana Devil" came out in late 1952 and created a sensation with audiences and exhibitors, kicking off the 3D craze. The use of two monitors with polarized lenses mimics the same method used for 3D theatrical films.
By 1954, when the Duoscopic was first seen in these publicity photos, the 3D fad had started to fade. I have to wonder if DuMont started researching 3D TV, then found it impractical (difficulty synchronizing the two signals?) or simply waited a little too long to announce it, with the 3D fad passing, and "rejiggered" the technology as a way for two people to watch two different television programs.
If they were pursuing 3D television research, and 3D stayed popular, it might have given them leverage to get additional channels in major markets - the system would have required TV stations transmitting the same program on two channels or some wider bandwidth solution to transmit left-right image pairs. DuMont could have argued for two UHFslots or a VHF
and UHF slot for 3D programming. In other words, they might have seen it as a way to get the FCC to push for more channels and opening up of the UHF band to television.
If you look at the idea - using two CRTs and polarized lenses to watch two different shows - the idea seems kinda wacky. But, if you think about how hot 3D was for awhile and that it used the same technology, then this Frankenstein TV makes sense, at least to me.
Here's another jigsaw piece to this mystery. DuMont discussed the 3D system made for the Atomic Energy Commission and noted that his engineers were working on a 3D system they would demonstrate publicly:
That's from the Apr-Jun 1953 issue of Broadcasting, which would have been at the height of the 3D craze. The craze started to pass later that year. The images of the prototype Duoscopic on your DuMont Duoscopic page are listed as being from the March 1954 edition of Popular Science. The Broadcasting article really strengthens my theory that the Duoscopic set was intended as a "comparable" 3D television.
It's interesting that the above Broadcasting article references the Atomic Energy Commission 3D system developed by DuMont in 50 and, in mid-53, a "compatible" 3D system the Dumont engineers were working on. The original AEC 3D system was "side by side" and would give viewers two images on the screen. If Duoscopic were used for 3D, with two full screen images broadcast simultaneously, it would be "compatible", with either the left or right image broadcast on a regular channel and the corresponding image on a different channel (perhaps in the UHF band?). I still think it might be connected to Dumont's efforts to figure out a way to get more station licenses and open up the UHF band at that time.
And here's another one I dug up from a 1953 edition of the Independent Exhibtors Film Bulletin
"Three-dimensional television was unveiled by ABC with the 'Space Patrol' show from KECA-TV in Hollywood going out to bespectacled newsmen for an experimental viewing a the downtown Los Angeles Biltmore Hotel. Verdict: spotty stereoscopic illusion, sometimes true, sometimes not, ofttimes jumpy. Video 3d commercial still a good way off."
There's also this that mention the test, but I'm not sure what his source is:
"In the early 1950s, ABC was granted permission by the Federal Communications Commission to explore the feasibility of 3-D TV. On April 29, 1953 the network ran a trial live broadcast of the series SPACE PATROL in Los Angeles at the National Association of Radio and Television Broadcasters 31st Annual gathering. The ABC affiliate station KECA-TV aired the show but it appeared as only a blur unless viewers had a pair of special Polaroid lenses."
There's a slight chance that this test might have been kinescoped with a matching pair left and right reels. At that time, many shows were networked using kinescopes, so it might make sense they would do a matching set of kinescopes to test how the 3d held up on a film version of the telecast. It's only a slight chance, but would put it on the 3d archives radar as something to look out for in archives.