NAEB Newsletter (Mar 1958)

TV TECHNICAL TIPS —Cecil S. Bidlack In early February, one of the most recent technical developments was demonstrated to newsmen by the Blonder-Tongue Labs, of Newark, N. J. It was Bi- Tran, a system of TV broadcasting which allows two programs to be broadcast over the same television channel. This is a “compatible” system which may be applied to double the number of programs received on a single channel. As the system would work, each channel would be divided into an “A” and a “B” portion. The “A” portion would contain present commercial or educa¬ tional programming as now provided. The “B” por¬ tion would be used for special services not now ac¬ corded television time and would be received only if the viewer elected to decode the signal at his receiver. At the demonstration, the regular broadcast pro¬ gram (program “A”) was seen on the receiver screen. When the decoder was switched on, program “B”, a closed circuit picture, appeared on the screen. Those present at the demonstration commented that the multiplexed program was inferior in resolution and contrast to the regular program. However Blonder- Tongue officials stated that the demonstration was primarily to show the feasibility of the system and that the system required refinement to improve pic¬ ture quality on the the multiplexed channel. It was stated that it would cost approximately $5,000 to modify transmitting equipment for Bi- Tran and about $60 for a decoder for the home re¬ ceiver. Further demonstrations will be held for radio and television broadcasters as well as industry and military leaders, educators, medical and governmental specialists. ***** Two papers of interest to technical personnel at NAEB stations and production centers will be in the mail soon. The first, “Film in Television” by Rodger J. Ross of the Canadian Broadcasting Corporation is a discussion of the technical quality of television film from the standpoint of the television broadcaster. The second is a “how-to-do-it” paper by Mel’ Haas of the WOI staff. It details their method of balancing crowd noise at sports broadcasts automatically when the announcer uses his mike cut-off or “cough” but¬ ton. It’s called “Automatic Crowd vs. Announcer Balance.” These papers will be mailed to chief radio and tele¬ vision engineers on our Technical Directory list. We have extra copies available to send upon request to others wishing them. * * * * * WTTW has expanded its kinescope recording serv¬ ice for outside agencies by the installation of a sec¬ ond kinescope recorder, according to Duane Weise, chief engineer of the Channel 11 Chicago ETV sta¬ tion. They are equipped to record either off-the-air from Chicago stations or by direct line from their own or remote studios. The station has also issued a new brochure cover¬ ing the WTTW-TV Recording Service which includes sample video recording costs. Revenue from the re¬ cording service is applied to the operation of WTTW. ***** A new line of closed circuit vidicon television equipment has just been announced by the General Precision Laboratory, Inc., Pleasantville, N. Y. The model PD-250 camera incorporates a five-inch elec¬ tronic viewfinder, a four-lens turret and either port¬ able or rack-mounted control equipment. For studio installations a control console is available, equipped with a 14-inch picture monitor, a five-inch waveform monitor and rack mounted control unit with remote control panel. The PD-250 camera is priced at $1,750 and operates from an external RETMA sync or an in¬ ternal sync generator. Where budget requirements are restrictive, the model PD-250 camera priced at $1,250 is self contained and provides either video or RF output. It is equipped with a three lens turret as standard equipment but has no viewfinder. ***** Glen Southworth, chief engineer of KWSC, the State College of Washington at Pullman, is the author of an article on page 100 of the February 14 elec¬ tronics. The article outlines a method of determining optimum electronic focus of television cameras and film chains by a special bar chart and by adjusting focus controls for maximum response of peaks on the waveform monitor. This chart, developed by Mr. Southworth, also permits rapid determination of the system resolution and relative resolving power of dif¬ ferent camera lenses. ***** February 1958 Electronic Industries contains a re¬ port on progress achieved by the EIA Committee, Microwave Relay Systems for Communication (TR- 14) on “Standardizing Microwave Communication Systems.” Due to the many and varied uses of micro- wave systems, it has been found necessary to stand- MARCH, 1958