In article ,
Michael A. Terrell wrote:
JVC was part of a small consortium that bought the rights to Ampex's
cartridge video tape design when they decided not to enter the consumer
video tape market. IIRC, they paid a measly $10,000 for everything.

Didn't know that. If you Google on helical scan the hits I looked at
credit Ampex with inventing this in '56 - but of course the original 2"
quadruplex pro machines weren't helical scan. They had the head at right
angles to the tape and achieved head wrap with vacuum. Four heads were
needed on the drum so one was always in contact with the tape - hence the
name. This was impractical for domestic use as you need a clean supply of
compressed air. Helical scan gets round this by having the head just off
in line with the tape and records along, rather than across, the tape and
only needs two heads on the drum. The tape itself can deform enough for
good head contact so no vacuum needed.

Ampex pro helical scan - 1" C Format - machines didn't appear until the
late '60s, although others had used it for semi-pro apps before.

So I do wonder who holds the patent on helical scan? More Googling is
needed...

--
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Dave Plowman London SW
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