[QuadList] Mobile Quad VTRs

[Peter Ford]

Hi Ian & the group

Got your pics now thanks......  I've sent you an email direct.

When I was at the Tv One centre at Avalon, Wellington (now Television New 
Zealand) we used to wheel an AVR2 (and air compressor) into the back of a 
Bedford Truck and used it in conjunction with the outside broadcast truck.

The guys at the Christchurch studio did the same thing.  One night the 
Christchurch crew recorded a celebrity dinner for replay on TV One from 
Avalon.  However when we received the quad tapes and checked them, the 
picture kept jumping sideways and was rejected for transmission.

The result was an investigation into what went wrong.  Eventually discovered 
that someone had played with the SPG in the Christchurch OB van and had 
turned off the 25 Hz burst offset (Only applicable to PAL).  Everything 
looked ok during recording and during a check replay at the venue.  The 
problem only showed up when the tapes were played at the transmission centre 
(SPG in "normal" mode).

TBCs use leading edge of sync and third cycle of burst as Luminance and 
Colour references.  In the PAL system burst is locked to horizontal sync 
with a 25 Hz offset so that if strobing occurs the strobing lines are 
diagonal rather than vertical and therefore less objectionable.  Thus the 
cycles of burst constantly move in relation to H sync with a repitition rate 
of every eight field.  A good idea but a problem for tape machines.  In PAL 
tape editing can be done following the 4 field sequence as per NTSC but for 
Animation editing the 8 field sequence had to be followed to avoid a 
sideways jump at the edits.

Peter Ford

>
> Hi Peter
>
> Yes tiz I
>
> Still not xx!! ??xx retired
>
> Images were sent as attachments ....got back to me OK
>
> I will contact off list
>
> cheers
>

> Hi Ian
>
> There isn't a link to your picture???.....but I've now realized we have
> met.  You must have been at Vidcom in Auckland back in late 70's.  About
> a year ago I restored/transferred a couple of interesting quad tapes,
> one showing off the Vidcom facility and another of "video art" playing
> with feedback through the vision mixer.  I came across them restoring
> commercials made in 70's and 80' for the NZ Film Archive.
>
> Mid 90's you were at Omnicon in Sydney.  My company purchased a Rank
> Cintel Mk3 from you but that is story for another day!
>
> Peter Ford
> The Kiwi Member
>