Radio age research, manufacturing, communications, broadcasting, television (1941)

Imag-e Orthicon tube, or 'eye,' used in the camera, is so accurate that it is unnecessary to introduce special controls to balance the three pri- mary colors for proper blending. Its light sensitivity is such that studio productions can be picked up with much less light than now used in the studio for black-and-white television. When this camera 'eye' is used to pick up color, a disk com- prising red, green and blue filters revolves between the camera lens and the face of the tube. "Receiving equipment consisted of a special 12-inch RCA Kinescope installed within a revolving drum carrying three equally spaced color filters. "Interesting as these tests have been, we are convinced through our achievements in all-electronic black- and-white television that any me- chanical color system is outmoded. Dr. Jolliffe called attention to the fact that the color demonstration employed a directional beam trans- mitter and parabolic antenna. The power was 1/20 of a watt, which is infinitesimal compared with the 50,000-watt transmitters used by standard broadcasting stations. A new electron tube developed during the war made this accomplishment possible on a carrier frequency of 10,000 megacycles — a frequency twenty times higher than any used heretofore in television. The wave- length at such a frequency is only three centimeters. New Transmission Methods A new method of transmission used in the demonstration permits sound-and-sight signals to be car- ried on the same wave. The sound is transmitted during the very brief periods when the scanning beam is inactive and insures high fidelity reproduction. "On the lower frequencies, tele- vision black-and-white transmitters now can be built to operate with at least 5 kilowatts up to 300 mega- cycles. New antennas can be built to make the effective power of 5- kilowatt transmitters the equiva- lent of 20 to 50-kilowatts output. SELTZER WATER SQUIRTED AT STEREO- SCOPIC TELEVISION CAMERA GIVES VIEW- ERS A THREE-DIMENSIONAL THRILL. Thus it is now possible to deliver all the power necessary on all 13 channels assigned by the FCC to commercial television." Dr. Jolliffe explained that at pres- ent there are two possible methods of producing color television—one using mechanical filters and the other all-electronic. "We look forward to the day," he continued, "when we will have an all-electronic color system. As with black-and-white television, we be- lieve that the electronic system will be far more satisfactory and prac- tical as a service to the home than anything that can be done mechan- ically. Rotating Disk Mixes Colors "In our demonstration today of the mechanical system, we were shown no fundamental advances in color television as such," Dr. Jol- liffe pointed out. "Actually the sys- tem of color television which has been demonstrated today is based almost entirely on the elements and apparatus of our all-electronic, black-and-white television system. We have merely added motor-driven color filters to the transmitter and receiver which enable us to trans- mit the red, green and blue com- ponents of the televised material in rapid sequence — so fast that the color components appear to be di- rectly overlaid. "With the development of the Iconoscope, Kinescope, Orthicon and other electron tubes in RCA Lab- oratories, an excellent black-and- white, all-electronic system of tele- vision has been produced," said Dr. Jolliffe. "It has no motors or whirl- ing disks. It is practical and sim- ple to operate in the home. Great Strides in Tube Design "The latest cathode - ray tubes used in all the new receivers dem- onstrated today were far more effi- cient than any publicly demon- strated previously. They revealed that great strides had been made in the development and use of fluor- escent materials in cathode-ray tube manufacture during the war. In the new tubes the fluorescent screen on which the image appears in black-and-white is backed up with a very thin coating of aluminum which permits the use of higher voltages than formerly. The alum- inum film acts as a mirror prevent- ing loss of light inside the tube thereby greatly improving picture brilliance and contrast. Dr. Jolliffe concluded: "There is no technical reason for further delay in giving television to mil- lions of Americans, as a new me- dium Oi infcrmation, education and entertainment. "Black - and - white television is ready for service to the public. We have all of the elements necessary for the immediate expansion of a satisfactory television service to the home on a national scale." [RADIO AGE 6]