[QuadList] Guerilla splices (was RCA types) (Joe Owens)
Dennis Degan
DennyD1 at verizon.net
Sun Jan 11 13:40:17 CST 2009
On Jan 9, 2009, at 9:02 PM, Phillip G. Shaw wrote:
> Splices Technical:
> Editing on Quad: The Control Track (240HZ) has a 30 HZ frame pulse
recorded (not to be confused with Color Frame) that the Capstan Servo
uses to lock the picture to the correct B&W Vertical field sequence.
This frame pulse can be used to mechanically splice tapes together with
a 50% chance you have correct color framing. The result of a bad edit
was a color flash at the Edit. All tape machines used a Control track
frame pulse to lock the servos, that is why you can't edit the wrong
"field" sequence.
I contradict:
Well, you COULD edit the wrong field sequence . . . with dire results.
;)
Phil also said:
> Network Trivia:
> The Color timing & phase of those times was sloppy but within the
window of the technology. In 1984 I was the Broadcast Systems design
engineer for NBC Political Conventions. The Locking Standard at that
time was Rubidium (Rub) that suffered a drifting figure eight error.
The Field Guys would coordinate with NBC-NY and be Wolf'ed ( NBC term
used for adjusting) into phase (zero beat).
I add:
These were the days when local sync gens were run using either
rubidium or cesium atomic clock references. Cesium was the 'gold
standard' while rubidium was the 'silver'. Both were many orders of
magnitude more stable than quartz crystal, which was what most TV
stations used in their house reference sync generators.
Quartz-referenced sync generators required that the quartz oscillator
be mounted in an 'oven' to maintain the crystal's temperature which
will better stabilize its frequency. Quartz-referenced sync gens were
unsuitable for use in network backhauls because they could not
adequately maintain their stability for long periods. The coordination
Phil referred to above was needed so that a field remote unit could be
video-timed to match into the NBC-NY release studio's video switcher
just as if it was a locally-synched video source. Back in 1978, this
used to be done at least twice a day on the link between Washington and
New York in order to 'line up' the incoming Washington feed for the
Today Show and Nightly News.
Phil continued:
> The Sync Standards & distribution for CBC & ABC , of the Broadcast
Pool, became my responsibility. I meet with Engineering/operations of
the other network to find out how they accomplished phasing between
them.
> A) On Mondays NBC looked at CBS and adjusted thier NBC Rub's for a
Zero Beat.
> B) On Wednesdays ABC looked at NBC and adjusted their ABC Rub's for a
Zero Beat
> C) On Fridays CBS looked at ABC and adjusted their CBS Rub's for a
Zero Beat
I say:
When I worked at NBC (the first time) in 1978, I discussed timing and
reference with an engineer who worked in Central. He told me at the
time that NBC and CBS used rubidium oscillators for their New York
central sync generators' references while ABC used a cesium oscillator
reference (ie, more stable). He said that because of this, NBC and CBS
would periodically check their rubidium 3.58MHz oscillator against the
ABC cesium 3.58MHz oscillator, thereby making ABC the master reference
for all of the New York-originated networks. I don't remember if he
said what ABC used as a MASTER master reference, but it was probably
WWV.
Dennis Degan, Editor-Consultant-Knowledge Bank
NBC Today Show, New York
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