HI Steve,
Thanks for the article. I emailed it to my father and here is an excerpt of his reply.
Quote:
That article was written in 1956, my first year at Drexel.
I must have bought the RCA 630 a year or two before that because I didn't have time to play with electronics while in college.
The article I found was in Popular Electronics I think. At that time, say 1954, the CBS system had been adopted by the FCC but only experimental broadcasts were being made at that time, maybe an hour a day. The CBS system used three picture signals simultaneously or something like that and took much more bandwidth, say two or three times and was not compatable with the NTSC B/W signal. The country was not ready to throw out their black and white sets.
Since the CBS system was never broadcast to the public, I lost interest and I doubt that I could have ever built the color convertor anyway without test equipment. And the mechanical color wheel was hard to make, being almost three feet in diameter.
The article you sent is very interesting. I never knew anyone thought of using the NTSC color signal to drive a color wheel over a black and white picture tube. Of course, it should work although the colors may not be as fast as a color tube. Most of the NTSC signal is luminance which gives the resolution for fine detail with the color being a small part of the signal at low resolution.
That article attemps to decode the color after the B/W set tunes the station. then applies the color signals to the tube in synchronism with the color wheel.
But if you wanted to try it with one of your small B/W tubes, you could use a color chassis which already has all the color demodulation and delay lines built in with the output being three RGB signals to apply to the color guns. So all you really have to build is that tritch triode circuit (tri-stable switch V4a,b V5a,b) to switch the Red, Blue and Green signals to the monochrome tube gun. Then follow it with the two-tube synchronizing circuit (V7 and V8) for controlling the color wheel. Of course build a color wheel and motor also. Would be an interesting project for a 5-inch TV.
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Interesting he mentions a 5 inch tube. He's probablly thinking about one of my 5AXP4 or 8XP4 test tubes. Since I thought about the possibility of a standard CRT not being bright enough I thought using an early projection crt directly viewed would give the brightness.
Take care,
Paul