First Mobile TV Units for the Army
TV Units For The Army
The Army makes extensive use of closed circuit television; educational video tapes produced by live mobile TV units (Fig. 1) are played back on one of the world's largest closed circuit TV systems composed of 24 Army bases and schools.
Video tape eliminates or minimizes problems associated with film production and use. Instant replay of a scene for on-the-spot evaluation with no need for film developing, easier editing, and the ability to update, erase and reuse the tape are some of the advantates gained. Training tapes may also originate from a central source and be piped by closed circuit TV to hundreds of classrooms simultaneously, thus saving costs on duplicate films and film projectors. Much less time elapses between the tape's original production and its use in the classroom.
The mobile TV units are located on 30 ft. trailers, custom-built by Fruehauf to Ampex Corp specifications. The interiors of the vans provide three basic operating areas: video control area, audio control area, and Videotape recorder and film chain area. (Fig. 2).
Workbench areas at each end of a van are integrated with the storage facilities for three Ampex/Marconi 322V vidicon TV cameras, as well as storage for lenses, microphones, test equipment, spare parts, equipment manuals, records, films, and video tapes. Cabinets under the floor of the van, accessible from the outside, hold the microphone boom and stands, camera tripods and dollies, a lighting package, and eight camera cable reels on curbside with a total capacity of 1000 feet of camera cable.
An outboard connector panel, in the curbside reel storage compartment, enables connection of input and output cables to the van system. Connectors are: three video inputs, four microphone inputs, three auxilary audio input/outputs, two wireless microphone antenna inputs, and two TV transmitter RF outputs.
A working platform of the roof is fitted with recessed tiedowns for securing camera tripods under high wind conditions or while the van is in motion. A removable guard-rail provides further protection.
Video Control Area
Located at the center of the van, this area consists of three racks of equipment (Fig. 3). The main items consise of an Ampex control panel for remotely controlling three Ampex 322V vidicon cameras, Dynair video switcher/fader, special effects generator, and Dage film chain remote control panel, all grouped for easy operation by one man. Other equipment includes a Conrac 8 in. monitor and Tektronix 529 waveform monitor for each of the three cameras outside the van and for the film chain camera. Other Conrac 8 in. monitors in the control rack are for video tape, special effects, remote input and preview.
A Conrac 14 in. monitor and Tektronix RM-529 waveform monitor, along with an Ampex audio amplifier/speaker combination, monitor the program as it is taped or as it is fed directly from the van to an external video recorder or TV distribution system. Futher equipment includes a Dage dual sync generator, Synair video and pulse distribution amplifiers, Tele-Instruments, 12-channel RF transmitter for feeding standard TV sets directrly from the outboard connector panel, film chain camera control unit, audio and video patch panels, Alma audio distribution amplifier, Telemet video test signal generator, and rack AC power distribution panel.
Film Chain, Videotape Recorder Area
An Ampex VR-1100 videotape recorder with Inter- (continued below)
sync servo system, Amtec time correction system, video processing amplifier
and air-beating rotating video head, enable video and audio recording
on a 2 in. wide magnetic tape. Up to 3 hours of program material may
be recorded on a single 14 in. reel. Input and output video of the recorder
may be monitored on the 14 in. picture monitor and oscilloscope waveform
monitor located in the monitor bridge above the recorder. Input and
output audio may be monitored by means of the audio amplifier/speaker
in the monitor bridge.