Color video tape recorders (V.T.R.'s) in the '50 and '60's

[Dave A]

Rvonse,

When the early 2" quad machines came out (and until the late 60's or so) the only color monitor available to stations was the 21" round-tube RCA TM-21x series of monitors and the same size from Conrac. Too big for direct installation. There would be a TM nearby on a switcher to monitor all the machines a station had. The B&W monitor was a confidence monitor only. It would tell you if you had a head clog on one of the heads.

Even without a color monitor, using the vectorscope and a waveform monitor mounted on each machine, the operator could set video levels on all four heads on the waveform and the color on the vectorscope with the color bar peaks hitting the appropriately marked color boxes on the graticule.

Because the tape may have been (and probably was) recorded on a different machine with a different head assembly, you had to set video play levels on all four heads plus a master video level. They all had their own charcteristics so no two head assemblies were equal. Record bias, playback bias, head wear, etc.

The networks would track what head was used to record a tape and all efforts were used to get that same head installed to play back tapes for the best playback to prevent "banding"...the obvious horizontal stripes from the four heads that can be seen on some poorly recorded or played tapes on different head assemblies.

If you were in a hurry setting up the tape, you would throw the TM to "blue only" and adjust the color phase (tint) so that the two center blue bars were equally bright and just adjust the video levels on the fly as it played.

If anyone has the RCA Broadcast News library, you can see an article on my old station WCEE-TV, Rockford, Il somewhere in the late '65 or early '66 editions. It was portrayed as a model station of the day. If you look closely at the photo of their quad machines, you can see a GE Portacolor used as a color monitor that was modified for direct video in. I guess they ran out of startup money.

Dave A