[QuadList] RCA Models

[Dale Lamm]

Until joining this list, I'd never heard of an 8-head format for 2 inch 
tape. I gather the main idea was to orient the pole pieces at some angle 
with respect to each adjacent piece, then you could lay down two wideband 
signals (perhaps video) at the same time, yet keep a measure of isolation. 
Especially with an FM mod-demod, the capture effect would bolster channel 
separation. There must have been a tiny track width with a small physical 
separation. Recording one track on top of another would likely erase the 
first track, because of the constant FM carrier. Please, someone with some 
deep understanding of this kludge, tell us more.

What a hack! Was this for 3-D TV? [grin]

Or was this simply to give quad a "confidence head"?

Do you think it would be possible to record channel-A in the morning, then 
go back and do a 60-minute insert using channel-B video in the afternoon? 
Wow, two programs on one piece of tape! Don't need no stinkin' digital 
compression.

I can see it now...

SALESMAN: Sir, if you buy this 8-headed recorder you can cut your tape costs 
in half!

GENERAL MANAGER: That's wonderful! I could also liquidate some of my VTR's 
and lay off a tape maintenance person!


[snip]

If the octaplex recorder turned on every other head, it would be a standard
quad recording, but with a 5-mil track, so I'm pretty sure that's not what
was going on.  I think I get the "picture" that you are describing, and I
assume that maybe if you were able to center the head between the two
tracks, then perhaps the demod output would alternate between the stronger
fields as they passed by.  I can't imagine that the results would be very
good, but more to the point, I still can't imagine why the octaplex would
have been used in the first place.  The only purpose is 2-channel recording,
and I assume from what you have said that what you ended up with was one
continuous picture, not 8 lines of one image alternated with 8 lines of a
different image.

[end]