[QuadList] RCA Models

[Don Norwood]

Hi Dale:

The track specifications vary depending on exactly what was being done.  In 
the case of the systems that were essentially "dual-track quads", the heads 
were 5 mil and tape ran at 15 ips so each track was distinct but with half 
the guard band dimension of standard quad.  For some of the slower speed 
units as well as instrumentation recorders, there were other track 
configurations.  I'm not aware of any machines that allowed anything other 
than simultaneous recording of both tracks.  That was the whole purpose of 
the design.

Don

----- Original Message ----- 
From: "Dale Lamm" <dlamm1 at neo.rr.com>
To: "Quad List" <quadlist at quadvideotapegroup.com>
Sent: Saturday, February 26, 2011 4:29 PM
Subject: Re: [QuadList] RCA Models


> 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]
>
>
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