NAEB Newsletter (May 1957)

to the tube elements. After aging, the tubes are checked on a SECO Grid Circuit tube tester, which indicates control grid emission, grid to cathode shorts, cathode to heater shorts, and gaseous conditions. Another 5 to 10 per cent of the aged tubes fail to pass this test and are returned for replacement. The remaining tubes are then placed in stock to be used when the occasion demands. Larry Brogger, KUOM chief engineer, has pro¬ mised to furnish us details on the KUOM tube ager which we will duplicate and pass on to you. He believes this equipment will pay for itself in a year’s time by locating sub-standard “new” tubes, to say nothing of the maintenance time saved by knowing that a tube is good before it is used in equipment. Also as a result of the use of this procedure, he has become convinced that an occasional routine check of tubes in operating equipment is advantage¬ ous in maintaining the equipment in peak operating condition. * * * * I spent some time with Berten Holmberg, chief engineer of KTCA, the Twin City Area ETV Corpor¬ ation station. The KTCA transmitter has been in¬ stalled in the KUOM transmitter house, proof of performance tests have been completed, and they have had a test pattern on the air on Channel 2. Present plans call for programming to begin in September, 1957. KTCA offices are located at present in a tempor¬ ary building on the Agriculture campus of the Univ¬ ersity of Minnesota (which will also house live studio and film equipment). Work is about to be started on the installation of studio equipment. Bert has had his physical activity severely slowed because he tore a tendon in his left heel in an attempt to get away from the KTCA tower when a bolt was dropped. Now that the cast has been removed and the crutches discarded, he hopes soon to be going full speed ahead. * * * * The NAEB Engineering Committee held a short meeting in Chicago Monday, April 8, prior to the NARTB Convention and Broadcast Engineering Conference. Six of the 10 committee members were present. * * * * Speaking of the NARTB Convention, I saw per¬ haps 20 engineers from educational radio and TV stations in attendance. No doubt there were others whom I didn’t happen to meet or see. Total reg¬ istration for the Convention was 2358, with 577 reg¬ istered as engineers. Some excellent papers were presented during the 3 full days devoted to the presentation of engineering papers. Eleven of these papers covered radio sub¬ jects, and 18 were devoted to TV engineering. * * * * I have no idea how many manufacturers were represented at the Equipment Exposition. Space in the Conrad Hilton Exhibition Hall was filled and there were a number of equipment representatives exhibiting on the 5th or 6th floors of the hotel. Program services, networks and others were also there providing something of interest to everyone in the broadcast industry. As I saw it, the theme of the NARTB equipment exposition was “automation,” with automatic devices being displayed for both radio and TV programming. These automatic devices were shown by Gates, Ampex, and General Electric. RCA also is working on an automatic program device. Vidicon equipment was much in evidence. RCA displayed its new, broadcast quality vidicon camera. Kin-Tel, Sarkes-Tarzian, Dage and General Electric also were showing vidicon camera equipment for live and film use. In much of this equipment the film and live camera chassis is interchangeable. In the field of video recording, Dage and Sarkes- Tarzian were showing 16mm kinescope recording equipment built to sell for less than $8000. Ampex demonstrated its videotape recorder in the recently completed installation at the ABC-TV studios. Three of the prototype models have been installed, the first to incorporate the much desired feature of universal playback. As a result of non-interchange¬ ability on earlier prototype models, CBS solved this problem by storing the recording head with the pro¬ gram tape in order to accomplish a 4 week delay on the Arthur Godfrey programs. Tape continues to be the major problem of video¬ tape recording, and tape manufacturers are working hard to solve tape problems. Some tapes now have a life of 200 passes—100 recordings and 100 play¬ backs. An hour’s tape costs $200, so when this life is achieved, cost is only $2 per hour. However, cost per hour skyrockets when the tape only lasts 10 passes. Another item of interest displayed was a device to reduce, “burn in” on image orthicon cameras. It consists of a mechanism to oscillate the lens board of the TV camera, at the same time providing an electrical cancellation of the resulting vertical and horizontal motion. It was demonstrated with an image orthicon with over 1000 hours service which had been discarded because of burn in. The camera was left stationary on a test pattern and, due to the action of the device, showed no burn. With the device turned off a “burn MAY, 1957 7