Ampex 2" Helical Video Format
Ampex 2" Helical Format Information:
Videotape Format: Ampex 2" Helical
In use: 1963-1970
Recording mode: Analog audio/video. Helical scan, non-segmented picture, with two video heads. One drum rotation per two fields of video. Two audio tracks.
Tape width: 2" wide, one mm thick.
Features: Less costly that quad. Provided a means of video recording for many purposes.
Existing machine longevity: Extremely rare.
Videotape longevity: Very low.
Prior usage: Primarily industrial and educational institutions, and airline in-flight movies.
Notes on the Ampex 2" Helical... Ampex introduced this format in 1962 with the VR 1500 and VR 660 models. With a linear tape speed of 3.7" per second, one reel of videotape could run as long as five hours. This was useful for longer form projects, such as in-flight airline movie showings. Apparently there was use of this format in government installations such as well. NASA used the VR 660 for some of the slow-scan video recording from Apollo 11 as the signals were received by earth stations in Australia.
Below is a quote from a former Ampex engineer, Jim Wheeler, regarding some Ampex 2" helical installations:
"In 1964, TWA had a corner on In-Flight movies. The CEO of Continental called the Ampex VP of Engineering and asked if we could develop a videotape system for showing movies. The VP set down with me and we had a plan roughed out within an hour of the phone call from Continental. The VP wanted a single large monitor in each cabin--just like the TWA system. I argued for individual monitors. We ended up with a compromise--which is what is common today.
I built a small box that converted the 28 volts DC aircraft power to 110 volts AC. This was the power source for the VR-660 helical videotape recorder. Ampex bought several hundred small TV monitors that would be mounted every other seat and on both the left and the right walls of the airplane. The wiring and monitors were installed by a company that did a poor job. There was crosstalk and RFI problems. Before this happened, I was transferred to another Division of Ampex in another town and never did hear how the crosstalk was handled.
I suspect that fiber-optic cables are used in today's In-Flight video Systems so crosstalk is not an issue.
Another version of "In-Flight" video was developed by the U.S. military. The U.S. Air Force installed a VR-660 in the tail area of every B-52 used in the Vietnam war. It was connected to a video camera that was pointed down. When a B-52 left Guam for a bombing run, the record button was activated. The VR-660 would record for six hours. Most of the recording was over water but it also showed what was actually bombed.
This is a good example of where archiving the entire 6-hour tape is not desired. 5 hours of ocean is very boring to watch."