Mechanical TelevisionA West Coast Western Visionette?
|
My modified Western Visionette |
A stock Western Visionette from Radiola Guy’s collection |
|---|
With it now pretty well established that the set was modified, the questions became “modified to what standard?” and “why don’t any of the standards that the SCM-01 work?” To answer this, I had to figure out two things, first the number of lines, and second the frame rate. As each hole in the scanning disc produces one line, figuring out the number of lines simply involved counting the number of holes in the disk. I made a mark with removable ink and started counting - 80-holes so 80 lines. Next, for the frame rate. The frame rate is the rotation rate of the disc which, since the motor is synchronous to the AC line, is just the speed of the motor. The nameplate on the motor states 900 RPM, and 900 rotations per minute divided by 60 seconds per minute is 15 rotations per second, so 15 frames per second. This made sense as that is the same frame rate as the Western television standard and the motor looks original and unmodified. With these two pieces of information, the horizontal frequency, that is the number of lines per second, can be computed easily as the number of frames per second (15) times the number of lines per frame (80), so 1200 lines per second. This answered one of the most important questions – why position “D” on the SCM-01 worked in the horizontal sense – it formed an image – but that image was unstable vertically. Looking at the manual for the SCM-01, position D corresponds to 60-lines at 20 frames per second which also works out to the same 1200Hz horizontal frequency, but the vertical frequency is 5Hz off – 20Hz instead of 15Hz resulting in an image that rolls vertically 5 times per second, which is what I saw.
With the basic parameters of the standard known, and the behavior of the set explained, the next question became “who used an 80/15p mechanical TV standard?” The answer, which came from the Early TV Foundation website , is that only one station ever used that standard, and that station was Don Lee Broadcasting, W6XAO out of LA. There is a fascinating article on this history of Don Lee and his engineer Harry R. Lubcke on the Early TV Foundation website at so the entire history will not be repeated here, but in short, Lee’s W6XS (later W6XAO) was the very first television station on the west coast and broadcast mechanical TV images from 1931 to 1936 in the 80-line standard devised by Lubcke. Because of the many competing mechanical TV standards in use in the USA, and the relative obscurity of W6SX, there appear to have been no commercial manufacturers of receivers for this standard. Instead, Lee recommended that viewers build their own receiver and provided plans to do so, based either on a disk either made by the viewer or one obtained from Remington Radio and Television Company 1815 Venice Blvd., LA.. Given the professionally made, but clearly not mass-produced (machined not stamped) appearance of the disk in my set, I will surmise that it is one of those purchased from Remington.
While one can never be sure exactly how many of any historical artifact still exist, after considerable research I have not turned up reference to any other known surviving examples of mechanical TV receivers for the 80-line standard. Thus, I appear to have stumbled upon the only known surviving example of a mechanical TV for this standard. I happen to be a west coast resident myself, having been born and raised in Seattle, WA, (and, in fact, having had my great grandparents homestead in the region around 1890) so I am especially honored to be the care-taker of an extremely rare west-coast mechanical TV. I plan to work with Darryl to add this standard to the converter and thus allow my modified Western Visionette to again display a television picture on the west coast.
Bio: Matthew D’Asaro, PhD, is a collector and amateur historian of technology based out of Seattle, WA, USA. Aside from television, he also has a large collection of early calculators and computers, electronic test equipment and scientific apparatus. He is a board member of the Early Television Foundation, active member and former vice president of the Puget Sound Antique Radio Association, and a ham radio operator (AI7RM). Matthew holds a Ph.D. and a Master’s degree in electrical engineering from MIT and is employed at Sea-Bird Scientific where he designs sensors for oceanographic research.
At home with other prewar sets |
On display at the 2024 ETF Convention |
|---|
A note about the history of this set. It was donated to the Museum in 2022 by the estate of John Hora. They donated a number of other sets, including a prewar RCA TRK-120. John lived in Grenada Hill, CA, which is just north of Hollywood, where Don Lee's TV station was located. Most of the Los Angeles area was on 50 Hz power in the 30s, and this scanner would not have worked in those areas, since the motor is synchronized to the power line. However, Hollywood and the surrounding area was 60 Hz, and this set would have worked there.