[BC] question for you engineers/videotape delay

[Xen Scott]

At 04:43 AM 01/01/2008 -0800, Jeffrey Kopp wrote:

>Further digression: I remember being told in about 1970 by our local
>public station's engineers that they'd attempted a video delay by
>stretching 2" tape between a pair of adjacent Ampex quads, presumably
>for the call-in shows they aired occasionally, but had found it impractical.
>(They bravely soldiered on without by careful call screening.) I'd bet
>some station did it, though.

Yes indeed.  See the pictures on Barry's web site in the section on
Ampex equipment.  At KYW-TV in Philadelphia, we used two side-by-side
Ampex VR2000 2" VTRs fitted with roller guides on the top corners.  The
tape path was from the supply reel on the left VTR through the head
channel, up past the take-up motor to the roller guide, then across to
another roller guide on the right VTR, down past the supply motor, through
the head channel assembly and up on to the take-up reel.  The left hand
VTR recorded and the right hand VTR played about seven seconds later.
It was possible to get a 20 sec. delay path with two additional roller
guides at the far corners of the VTRs.  It required a little practice to
get the tape path aligned.  The VTR delay was used regularly for the local
morning show which took phone calls.  Later, KYW-TV used a pair of VPR-2B
one inch VTRs fitted with a custom clutch for program delay.  Pictures are
at the same web site.

One mildly amusing story I can tell concerns the attempt to promote the
then failing 11pm news.  The promotions guy suggested inserting a promo
into the last commercial break in the network show that aired ahead
of the 11pm news.  The plan was to air the network show live until
the end of the last commercial break, then jump off the network and run
a 20 second 11pm news promo.  Following the promo, Master Control
would pick up the remaining portion of the network program via a
20 second videotape delay.  The 11pm local news started 20 seconds
late and was shortened by 20 seconds to make up the time and allow the
station to hit the network on time at 11:30p (later 11:35p).

The videotape delay was set up just after the 10pm network program
started so as to give the videotape operator time to get the delay
established.  The procedure was to have the delay VTR system record
directly from the network.  Master Control could then see the live
Network signal and the same thing 20 seconds later from the playback
VTR.

All worked well for many days until one night the VTR operator mistakenly
fed the videotape delay system with the program feed going to the
transmitter instead of the feed directly from the network.  Since the
two signals were the same up until the last commercial break, no one
noticed any difference.  When the last network commercial break finished,
Master Control jumped off the network and ran the 20 second 11pm news
promo.  Then Master Control went to the videotape delay, expecting to pick
up the rest of the network program, but got the 20 second 11pm news promo
again.  I'm told that the promo aired three times before Master Control
took the network signal direct to end the confusion.

Xen Scott
former KYW-TV tech.