1962 Helical Scan using 2" tape reels. Ampex had managed to keep competitors out of the videotape business by the use of its patents. But 1961, its audio tape equipment business was being seriously eroded by Sony's exclusive transistor circuits, and a license trade occured. When Sony brought the transistor PV100 helical scan to market the next year, it forced Ampex to do the same. Ampex had previously developed helical scan technology but sat on it hoping to keep its (exclusive) quad business alive. It didn't take a PhD to figure out that helical scan would eventually capture the videotape market place. What was in fact amazing was that it took another 16 years for it to happen and in the end only happened when Sony and Ampex decided to cooperate once again.
A fundemental flaw in the quad system is each track of video is limited to 2" of lengh, the width of the tape. In order to achieve the high writing speed of 130 feet per second it takes 24 tracks to record each frame of video. The output from the head is termed "segmented" and each one of these video segments must be corrected for timing errors (by the Amtec) or else venetian blind type horizontal bands become visible it the picture. Once video is out of the machine, these artifacts can't be fixed elsewhere.
There was never a truly "portable" quad VTR. KVCR did use its VR1000 in the field though. It was mounted in a 10-ton military design van truck (ambulance) donated by the local Civil Defense organization that had no use for it. Quad would never be small, light and battery operated, although a "transportable friendly" version was marketed in 1959. Whereas American Airlines in-flight movies used Sony 1" decks in 1964 and the Panasonic EIA(J) version saw flight time in F4 fighters during Vietnam, the helical scan could travel in fast company.
Helical scan is sometimes called "slant track" because it is layed down as a diagonal on the tape. While the first models used 2" wide tapes, that was probably because TV stations already had these on hand. The length of the track is determined by the size of of the headwheel, along with the number of heads, field/frame and wrap. The most common configuration became field recording with 2 heads and a half wrap. Under these conditions regardless of diameter, the headwheel turns at a comfortable 1800 rpm. (Half a revolution = one TV field) and because that parameter is essentially independent of tape speed, helical scan method has the unique feature of being able to produce a viewable picture at pause, slow motion, fast motion, or even reverse motion. Such 'trick play' is impossible with the Quad system.
A track length about 1 foot long for the recording of one tv field gives a headwheel diameter size of 8 inches and a writing speed of 60 feet per second. Notice we didn't even have to consider the tape width, or recording speed to figure this. Thus as the tape speed is slowed down, the only practical limitation is the audio fidelity of the linear track, and track spacing. 15 ips was overkill, 10.5 ips and 7.5 ips were the most common speeds for open reel designs. Cassette recorders would run the tape even slower, down to only 0.43 ips for VHS EP mode.
Tape did not have to be 2" wide either. In 1964 Sony came out with the 1" version that was very successful. I had one and it really did perform well, for black and white of course. And that was the sticking point because in the next few years, most stations would transition to color. But for the immediate time, B/W would do because this cost but a fraction of the price of a quad VTR and the tape cost for a given program time was about 1/3 as much.
But competition created the biggest problem, because by the next year Ampex also came out with its 1" variety, and Precision Instruments 1" and Matchtronics 1" and by 1968 there was also IVC 1", Grundig 1". Then there were different half inch tape versions from Sony, 3M and Concord. And you thought BETA-VHS was the first videotape war. There are all kinds of variations possible such as tape speed, headwheel diameter, type of wrap and number of heads, reel shape, even how the tape went on the reel, so each format ended up totally incapable of interchange. This really came unexpected to an industry that always had standardized interchangable audio and video components.
If you think about it, an audio tape reel made in 1950 (Soni-tape in those days) can be played even by the most modern version machine. Tape specifications have stayed compatible. That came about because the modern audio tape recorder was in fact developed in Nazi Germany as the magnetophone, and after the war, these patents were confiscated by the government. Ampex knew nothing about electronics or broadcasting which was probably a good thing. They did have experience in manufacturing small electric motors and that's what attracted them to the magnetophone device as a post-war industry. Nothing had to be changed, they could build an exact clone and it would work. Other companies outside the US made them also, all derived from the same original Nazi prototypes so all brands of equipment produced tapes that were interchangeable. And you thought Hitler's only contribution to society was to make the trains run on schedule.
With quad, Ampex held its own patents, and thus prevented any other company from making them. While this kept the product unit price high, it did create an orderly marketplace. RCA did manufacture some compatible VTRs under license, but basically quad was an Ampex exclusive. In 1956 the VR1000 sold for 25 times the price of a standard Ford or Chevy car. You could imagine that other equipment manufacturers wanted a piece of this action also. And what every television station really wanted was cheap. Consider the sticker shock of quad, plus they faced replacing the headwheel every 400 hours for $3000 and building a thousand reel library when just one spool of tape could run $100.
Ampex tried a new trick, rather than sell its new 1" product at a ruinous low price, they got SMPTE (Society of Motion Picture and Television Engineers) to make the Ampex design the only approved standard for broadcast helical scan videotape recording. SMPTE Type A. This avoided a direct market place confrontation. And no other manufacturer could legally copy the design precisely enough to meet the SMPTE standard without infringing on Ampex patent claims for its variety of helical scan. Sony and IVC both made better VTRs but were severely hampered in selling them to network stations which had the largest budgets to buy such things. Sony and IVC did managed to eclipse Ampex in the manufacture of broadcast cameras because Ampex failed to convert to color successfully.
As a "standard" SMPTE Type A was a joke. The Ampex Type A machine tolerances were sloppy and not only would they not interchange a tape between different recorders, it was not uncommon for tapes made on a recorder to not be playable on the SAME machine on a later date. It became common practice to number the tape machines and then mark every tape made so it could be played back on the same one. Another quirk of this model was that if power were applied while the tape was threaded, the motor would immediately burn up. Imagaine TV control room people scrambling after every power glitch to save as many machines as possible. Sony made its reputation in this era without SMPTE approval for making VTRs that worked dependably, a factor that broadcasters would remember in time to come.
next on the history of videotape, 1969 EIA(J) color under on 1/2" tape reels