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Here's another interesting chapter in the history of the Beta format, the time-lapse video recorders. Used primarily for surveillance, record keeping, detective and intelligence work, these were not your typical Beta. These recorder had the unique ability to compress time, so to speak. They did this by recording individual frames of video spaced out over preselected time intervals, usually 24, 48, 60, 96 or 180 hours. When the tapes were played back for viewing a large span was compressed and could be reviewed in a matter of minutes. The video source could be a single camera, a multiple video array system or a manned monitoring station. (Video arrays and monitoring stations either used split screen or cycled through different cameras in a rotational pattern.) The unit pictured above, the 2500, was the last and most sophisticated model produced by Navco Security Systems. They made two earlier models, the 2412 and the 2412 SB. You can get a pretty good feel for the size of the unit above if you compare the cassette door to the top and front of the VCR. They were big, and heavy too. Navco designed the specialized electronics and time-lapse circuitry, the chassis manufacturing and basic video electronics was contracted from NEC, who purchased some of the sub-assemblies from Sony. Click on the picture and you will see the three models. The first Navco Beta, the 2412, featured a variable speed stepping capstan that was capable of capturing from several frames per hour up to as many as a couple every minute. The 2412 SB was same machine but incorporated improved SuperBeta circuitry for producing a sharper picture. The last model, the 2500, featured improved servo motor tape handling and a super controlled speed system, this offered even more time interval options and better tape travel. It also featured Super High Band recording (switchable) with digital video recall. Clicking on the picture shows a close up of the function buttons and switches on the front panel of the model 2500. The Field advance feature, not found on consumer Betas, provided movement of the picture from frame to frame both backwards and forwards. This was done to allow for closer examination of the elements of a video being viewed. Click the picture again and the switch panel array appears. Notice the head hours clock (looks like a fuse) intended to notify a technician when a service interval was needed. The next picture is of the back of the VCR. Notice the flat cable connector and the RS 232 computer interface. This control flexibility allowed these units to be remotely triggered by an alarm system, motion detectors or heat sensors. The large finned heat sink was employed to keep the unit cool and is an indication that these units were built for durability. It was routine for them to sit in a secluded location quietly recording frame after frame of images over many long hours in banks, supermarkets, retail stores, automated teller machines, hospitals, guard houses, corporate headquarters; the list is long and extensive. If an incident occurred the recorded tape(s) acted as a record of the event within the cameras field of view which could be withdrawn, examined and evaluated. It was typical for the tapes to be rotated over a predetermined weekly schedule. To aid in locating selected scenes various types of identification methods were incorporated into the units software and recorded on to the tape as a number, time and/or date legend. Click on the picture and you can see that the tape path was heavily shielded to prevent stray magnetic fields from finding their way into the recorded image. Also, special formula tape was used that could withstand the repeated strikes of the video heads as the tape moved slowly around the video drum (the heads were spinning all the time recording was taking place). To help prolong head life a small ceramic heater produced a slight convection of air around the video drum which lifted the tape ever so slightly from surface to reduce friction. Click again and you can see the drum area inside the unit. Notice the designation "NEC" on the top of the green video disk rotor board (center of the drum). This identifies the manufacturer of the drum assembly. The next, and the last picture of the series, shows the electronics and mechanics located in the bottom of the machine. The reel motors, bottom center, came from Sony and were of the direct drive type found in many of their high end models. The drum and capstan motors near the top incorporated specialized hardware and electronics used to maintain the delicate, yet firm balance of tape tension and reverse braking during the stepping actions, once again a precision not found in a typical Beta VCR. A couple more things of interest. These time-lapse Betas were not able to play back conventional Beta recordings very well because they lacked the regular playback speeds. And they only recorded a single field of the picture, or to say it another way, each head recorded an independent scene and every one of those was made up of an individual picture. Each picture was not as sharp as a recording that used both heads to scan a picture, but is was very good for a device capable of covering so much recording time. To accomplish the single frame recording both video heads on the spinning disk were the same (with home video recorders each side has the recording gap slanted the opposite way to lessen crosstalk (see azimuth recording). Sound quality was not very good and even though audio playback was possible, it wasn't too practical since the it would be greatly compressed and mostly garbled. Eventually, all the time-lapse units became VHS but at one time this Beta was the top of the line and a stellar performer. To examine the connection interface located on the rear click here. ©Misterßetamax go to homepage |