Quadruplex Videotape - History

History

Time-shifting of television programming for the West Coast of the United States by the networks in the 1950s (in order to broadcast their programming at the same local time on the East and West Coasts) using kinescope films was quite a rushed and perilous ordeal. This was due to there being only three hours for the West Coast branches of the TV networks to receive video for the programming from the East Coast (live via leased microwave relay or coaxial cable circuits provided by the phone company (AT&T) at the time), and then to record such to kinescope films, and finally to develop the film to be aired three hours later on the West Coast. This usually meant the kinescope was aired almost immediately after it came straight out of the developing equipment, still warm from the film dryer. These were referred to by the networks as "hot kines". By 1954, the networks used more raw film stock for kinescopes than all of the Hollywood film studios combined, spending up to $4,000 per half hour. They were desperate to obtain a quicker, less expensive, and more practical solution.

In the early 1950s, Ampex and several other companies such as Bing Crosby Enterprises (BCE) and RCA were competing to release a videotape format. RCA and BCE did release working prototypes of their recorders, but their downfall was that they all used a longitudinal (stationary-head) method of recording, much like audio tape recorders. This meant that the tape had to be recorded at an extremely high speed (around 120 in (3,048 mm)/s) in order to accommodate sufficient bandwidth to reproduce an adequate video image (at least 2–3 MHz for a watchable image), in turn requiring large amounts of tape on large reels. At the same time, the BBC developed a similar stationary-head video tape recorder (VTR) system that saw some on-air use, called VERA (Vision Electronic Recording Apparatus).

Ampex, seeing the impracticality of the prototype BCE and RCA VTRs, started to develop a more practical videotape format with tape economy in mind, as well as providing a solution to the networks' West Coast delay woes. Starting in 1952, Ampex built the Mark I prototype VTR, using 2 in (51 mm)-wide tape. Ampex decided that instead of having the tape move fast across the head to record enough bandwidth for video, that the head would move fast across the tape instead. This resulted in the Mark I using arcuate scanning, which consisted of a spinning disk with a face (where the heads were mounted) which contacted the tape (as opposed to the edge of the headwheel with transverse quadrature scanning). This resulted in an arc-shaped track being recorded across the width of the tape. Arcuate scanning resulted in a head-to-tape speed of about 2,500 in (63,500 mm)/s, but problems with timebase stability of the reproduced video signal from the tape led Ampex to abandon arcuate scanning in favor of the more reliable transverse scanning system.

Ampex soldiered on throughout the mid-1950s with the Mark II and Mark III prototype recorders, which now used transverse scanning. The Mark II used frequency modulation for recording video to tape, resulting in a much-improved, but still noisy, video image (the Mark I had used amplitude modulation, which resulted in a very poor-quality video signal reproduced from the tape, underscored as well by the shortcomings of the machine's arcuate scanning), and the Mark III had improved signal-processing and servo electronics, resulting in perfect video reproduction.

The Mark III worked perfectly, but its appearance was quite that of a prototype, and not a finished, saleable product. It was in a makeshift wooden case, with several parts of its chassis externally mounted in partially filled racks. Ampex took the same components used to make the Mark III, and then built it as another machine, this time into a sleek metal console and fully populated rack-mount cases, and this became the Mark IV.

The Mark IV was the machine first publicly demonstrated at the National Association of Radio and Television Broadcasters (now the NAB) convention in Chicago on April 14, 1956. After William Lodge of CBS finished his speech, the Mark IV replayed his image and words almost immediately, causing "pandemonium" among the astonished attendees. The earlier Mark III was given some cosmetic improvements, and was also demonstrated at Ampex headquarters in Redwood City the same day. Both demonstrations were a success, and Ampex took $2 million in orders for the machine in four days.

Ampex later released the first manufactured models of Quad VTR based on the Mark IV which were also prototypes, the VRX-1000, of which 16 were made. Machines made afterward were the final production models, and were designated as the VR-1000.

In 1957, shortly after Ampex's introduction of the 2-inch quad format, RCA introduced a quad-compatible VTR, the TRT-1A. RCA referred to it as a "Television Tape Recorder", since the word "videotape" was a trademark of Ampex at the time.

RCA was able to make the TRT-1A and its later machines compatible with 2-inch quad because Ampex assisted RCA in doing so, as an expression of gratitude for RCA assisting Ampex with making their later quad machines after the VR-1000 color-capable. Initially, the VR-1000 was only natively capable of recording and playing back black and white video, but RCA had modified several VR-1000s to record color video for the NBC TV network (which RCA owned at the time) in the late 1950s, since NTSC color video programming was already underway at NBC.

Ampex developed and released updated and improved models of their quad decks, such as the second-generation VR-2000 in 1964 and its scaled-down economy version, the VR-1200, in 1966, and the AVR series of VTRs, AVR-1, AVR-2, and AVR-3 in the 1970s. The AVR-2 was the most compact of quad VTRs, using conventional 120 volt (V) single-phase household-type AC power to operate, rather than the 208 or 220 V three-phase AC power required by larger quad machines.

RCA released later models of quad VTRs as well, such as the TR-22, TR-70, and TR-600.

The Fernseh Div. of Bosch in Germany released the BCM-40 quadruplex VTR in the 1970s. It was only marketed in Europe, and was not sold in the U.S.

CBS was the first television network to use 2-inch quad videotape, using it for a West Coast delay of Douglas Edwards and the News on November 30, 1956. The CBS show Arthur Godfrey's Talent Scouts on December 24, 1956 became the first entertainment program to be broadcast live to the nation from New York and taped for a time-delayed rebroadcast in the Pacific Time Zone. On January 22, 1957, the NBC game show Truth or Consequences, produced in Hollywood, became the first program to be broadcast in all time zones from a prerecorded videotape. The Edsel Show, on October 13, 1957, was the first CBS entertainment program to be broadcast live to the nation from Hollywood, then tape-delayed for rebroadcast in the Pacific time zone.

The engineers at Ampex who worked on the development of 2-inch quadruplex videotape from the Mark I to the VR-1000 were Charles Ginsburg, Alex Maxey, Fred Pfost, Shelby Henderson, Charlie Anderson, and Ray Dolby (who later went on to found Dolby Laboratories).