[Boatanchors] Anybody remember the "Wobulator"?

[Richard Knoppow]

----- Original Message ----- 
From: "Bob W5UQ" <W5UQ at att.NET>
To: <wrcromwell at gmail.com>
Cc: <boatanchors at mailman.qth.net>
Sent: Thursday, December 22, 2011 6:10 AM
Subject: Re: [Boatanchors] Anybody remember the "Wobulator"?


> Wobulators were used for a lot of things in my time.
>
> One of the more interesting ones I remember is:
> I worked as an engineer at KTUL TV Ch. 8 Tulsa from 1958 
> to 1966 and our
> News Dept got a KINESCOPE Film transfer unit.
>
> A 16mm film camera was mounted to film a kinescope tube. 
> Since the tube
> scanned 525 lines(not all active) and we played it back on 
> the same type
> scanning system, the lines would not match up and lots of 
> detail was lost.
>
> SO... ENTER the professional kinescope  film transfer 
> unit, costing many
> thousands of dollars.  It was bought since its quality was 
> so good.
> It's main secret was the wobulator, which wobbled the scan 
> lines,
> allowing for better resolution and quality of picture in 
> the film
> transfer process.  It worked pretty good too. 
> Considering.
>
> Before that the mounted the camera in front of a TV 
> monitor had a
> resultant film picture that looked pretty soft and grainy. 
> So the
> wobulator really helped.
>
> Seems like we could adjust the "wobulation effect" for 
> best detail too.
> They also used a high intensity CRT with a coating that 
> caused the
> picture to be retained a bit longer but without "trails", 
> as I recall.
> Hard to remember and bring it all back.  Anyone remember 
> "travel ghosts"?
>
> Then the video tape recorder wiped the film/kinescope 
> transfer process out.
>
> That was a long time ago... things have really improved a 
> lot since
> then...   WOW...
> Bob   W5UQ

     Spot wobbler...  Making good kinescope recordings was 
not easy and I saw only a few that were even decent. Beside 
the wobbler some method had to be incorporated to compensate 
for the difference in frame rate: TV, in the USA, runs at 30 
FPS (B&W) and film at 24FPS. The compensation was done in 
the camera which had a special pull-down and shutter. 
Cameras had to be synchronized with the picture. Part of the 
loss of resolution came from the loss of half a field caused 
by the speed compensation. Also, despite the high-intensity 
phosphor the image on the film was low so rather fast, and 
grainy film had to be used. Video tape, when it came, was a 
revelation.
     BTW, while the term Kinescope was mostly associated 
with this method of TV recording it was, actually a 
regestered trade mark of RCA for its brand of picture tubes.
     In about the 1960's someone came up with a method of 
recording using direct exposure of film with an electron 
beam. These were effectively Kinescope records without the 
optical parts. I don't remember anymore how the speed 
difference compensation was done but I think electronically. 
The system was capable of making color records. Kinescopes 
continued to be made long after video tape recording came 
into general use mostly for archival use and many of the 
"classic" programs now offered on DVD are transferred from 
them. In the early days 2" tape was too valuable to archive 
it so the originals were usually bulk erased and the tape 
re-used. At least this was the practice at NBC in Burbank.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com