Cartrivision cassettes used 1/2 inch tape and a recording technique called "skip-field", which was a technique employed by recording only every third field and essentially playing it back three times to lengthen the capacity of the tape cartridges. The end product of this technique was a slightly hazy and jumpy picture. Cartrivision had over 100 pre-recorded titles (black cassettes) available for sale through retailers such as Sears. The cassettes for sale consisted of sports programs, do it yourself, education and travel, etc. Cartrivision also ran a service called the "Cartridge Rental Network". These movie cassettes (red) had to be rented through a process that usually involved receiving the tapes through UPS once they were ordered through the retailer, and then returning them back the same way. Needless to say this was a lot of work just to watch a movie and did not go over very well. Not only that, but the rental cassettes could only be viewed once at home. They could only be rewound using a special rewinding machine that only the retailers had. This was done to protect any profits that might be lost by the movie studios to repeat viewings.



Cartrivision also offered blank cassettes for sale for home recording. The Cartrivision recorder used either of two sizes of tape cartridges. The smaller cartridge contained sufficient tape for up to thirty minutes of playing time, while the larger cartridge had a playing time of up to 114 minutes. Certain tape cartridges had bilingual or stereo audio channels. In playing a bilingual tape, the selection of one or the other language is made by disconnecting the undesired channel through the insertion of a plastic plug into one or the other of auxiliary audio outputs at the back of the Cartrivision recorder. That leaves the desired channel connected to the speaker of the television set.





The Hardware:


The Cartrivision video tape recorder essentially came in only one configuration. The Cartrivision system was built into 25” console color TV’s made by Admiral, Teledyne Packard Bell, Emerson-Dumont, Sears, Roebuck Co., etc. There was also a prototype stand-alone video tape recorder that was developed but never went to market. One of the accessories that you could buy for the Cartrivision was the "Instant Replay TV Camera". From Cartrivision literature this is how they described the camera – “The Cartrivision system may be purchased today with an inexpensive black and white television camera. This camera performs a dual function. It makes possible home movies with sound and instant replay. It may also be used for a home surveillance or closed-circuit system”. There was also a microphone offered for sale for use with the camera but this seems to be a somewhat rare piece. The Cartrivision system was capable of stereo audio output, but this was only possible with some of the pre-recorded cartridges. Tapes recorded at home were recorded in mono.





How It Works:


One of the criteria for the Cartrivision Video Tape Recorder was the ability to play full movies without interruption. No inexpensive VTR of the cassette variety had been developed that would play more than an hour program and most of them played far less lengthy programs. The approach was taken with the Cartrivision system of a “skip-field” concept, which would allow the recording of one-third of the information normally available in a television signal without any apparent effect to the viewer, and as a consequence up to 110 minutes of programming was available on one cartridge.


During recording the tape moves at a fairly slow pace, 3.8 inches per second, while the record head which is mounted on a rotating scanner, moves past the tape at a very fast pace of 1200 rpm. The tape moves on a diagonal to the plane of the scanner rotation. The end result of this recording process is a series of helical tracks each about 9.5 inches long. Each track represents one frame of video information. The scanner disc incorporates three heads approximately 120 degrees apart. Only No. 1 head records, but during playback all three heads are utilized. The heads are mechanically staggered causing each head to read the same track during one revolution of the disc. The same field, though recorded once, is therefore essentially repeated three times during playback. The three heads are electronically switched so that output is produced only when the correct head is in tape contact.






Cartrivision operating manual