What Kind of Television?
To the television set owner the most important thing is the kind of picture he is going to have to look at. Today’s picture is made up of 525 lines and appears on a screen generally measuring not more than 9 x 12 inches. To get a better idea of what this means, imagine a sheet of paper the size of the present television screen. Streams of electrons “paint” a picture on it in varying shades of light and dark. The painting is done one line at a time, in much the same way that a page is typed on a typewriter.
A complete new picture—like a new page of 525 lines, each line a fraction of an inch lower than the preceding one—is painted 30 times a second. When the 525th line is completed at the bottom of the screen, a new picture is. instantaneously started at the top of the screen. With 30 new pictures every second the viewer gets the same effect of motion as he would get by running 30 frames of movie film through a projector every second.
To get some idea of how fast television pictures are painted, we can recall that the average typewritten page, single-spaced, has 2,000 characters including letters and punctuation marks, but not including spaces. One television picture has 260,000 characters, equal to about 130 pages of typewriting.
The Bible contains 3,500,000 letters and punctuation marks. Television transmits that number of characters in half a second.
If science is able to perfect the transmission of television pictures at high frequencies, more lines can be put on the screen. A 1,000-line picture would contain 585,000 characters and presumably be twice as good. In order to produce a 1,000-line picture, it will be necessary to alter completely the 525-line system. This means that in the event of a switch-over all receivers manufactured for 525-line television will become obsolete.
As a result of the FCC’s allocation proposals, manufacturers will go ahead after the war and produce sets for receiving the 525-line picture, and some, if not all, broadcasters will send out programs that can be picked up by these sets.
War improvements cut costs
Facilities for manufacturing electronic devices for wartime use will be available when peace comes for the production, of television receivers and equipment. This will bring down the price you will have to pay for your television set. For example, the prewar cathode-ray tube, the electronic tube that takes electrons and makes them paint a picture before your eyes, costs about $60. After the war this tube will cost only $20.
According to manufacturers, the first television sets will cost anywhere from $75 for table models to $600 for deluxe television-phonograph-radio combinations. The cost of a television receiver depends largely on the size of the picture, since the larger the picture, the more tubes and gadgets are needed. Prewar sets with a 9 x 12-inch picture had about 27 tubes for television reception only. After the war, it is expected that sets will show 18 x 24-inch pictures, large enough to be viewed comfortably in the average living room.
Systems of mirrors and lenses are now being developed to project on a screen television pictures picked up from the receiving tube. One such system consists of a spherical front mirror and an aspherical lens. The mirror looks like a shallow bowl; the lens is flat on one side, and the opposite side has a special surface contour. The mirror arrangement follows the principle of the reflecting telescope, used by astronomers for many years.
The projection system in the illustration on page 39 is mounted near the bottom of the receiver cabinet and it projects the image straight up onto a flat mirror inclined at 45 degrees. The mirror throws the image onto the screen or onto a translucent plate of glass built into the front of the cabinet. This arrangement presents the advantages of compactness, and the cabinet need not be much larger than the present floor-model radio console.
Prewar television pictures had a disagreeable greenish cast, caused by the fluorescent screen of the cathode-ray tube. Wartime research has created a new kind of fluorescent screen that gives a black and white picture almost as good as a newspaper half-tone.
The flat cathode-ray tube, used in 1941, made it necessary for the spectator to stand directly in front of the screen in order to see an undistorted picture. A new rounded tube has been developed during this war that throws the picture on a curved surface. This new tube gives a clearer picture that may be viewed from many comfortable angles.
Look before you buy
Unless you live 50 miles or less from New York, Chicago, Washington, Philadelphia, Schenectady, or Hollywood, you cannot, at the present moment, receive pictures on a television set. So don’t rush out and buy one right away or order one from a mail-order house as soon as they are available. First you had better make sure that you are within the transmitting area of a television station.
During wartime there are six commercial and three experimental television stations broadcasting regular programs and covering an area in which about 27,000,000 people live. Plans are under way for at least one national television network linking the major centers of population throughout the country. This network is not expected to be in operation before 1950, however.
Radio waves at television frequencies act somewhat like a powerful searchlight. Most picture-carrying waves will not follow the curve of the earth’s surface, nor will they go through a hill or even a building, like the radio waves which now carry sounds. Therefore, the service area of a single television transmitter is limited.
The quality of the picture reproduced on your set depends upon there being no intervening obstacles between it and the transmitter. It is desirable, therefore, to have both the sending and receiving antennas as high up in the air as is conveniently possible.
From a transmitter atop the Empire State Building it is possible at present to send pictures a distance of about 50 miles. Of course there are places not 5 miles from this transmitter where no pictures can be received or where reception is very poor because there are obstacles between the transmitting and receiving antennas.
Because of the very high frequencies involved, television programs cannot be transmitted by wire. This means that we cannot have a national network of television stations linked together by ordinary telephone wires as radio stations are. A solution to this problem may be found in the coaxial cable, a special wire that can carry high television frequencies. However, these cables are expensive. One well-known radio man estimated that a cable connecting New York and Los Angeles would cost nearly half a billion dollars. Plans are under way, nevertheless, for developing such a network.
Another possible solution to the problem of developing a television network may be a system of relay stations. Under this system, a program sent out by one station is picked up by another station 50 miles away. The second station re-broadcasts the program to a third station, which in turn rebroadcasts it to a fourth station, and so on.
There is every likelihood that by using the coaxial cable or the relay system, or a combination of the two, we will one day have a national television network. Today the television signal likes to stay near home, but science will find ways to make it venture out and eventually cover the world.
All this boils down to the fact that if you live in a smaller town, you’ll probably have to wait until a television station is set up nearby or until your town is made a link in a television network. If you live in a big city, you may start shopping for a set as soon as they come on the market.
Buying a television set is going to be like making an investment in a washing machine or an automobile. It will set you back from $100 up, and you’ll want to be sure of getting your money’s worth.
Before you start looking for a receiver, check up on the television station in your area and find out whether its programs interest you. What’s the use of buying a television set if the only programs you can get are ones you don’t like? The first time you see a television picture, your enthusiasm for the novelty of it will probably cause you to believe it a little better than it actually is. Don’t let the salesman double talk you into buying one before it is demonstrated in your home. Who knows, you may be living in a “dead spot” where it is not possible to pick up television pictures. Before you buy, sit down and watch television programs in your own home for at least one hour. Decide for yourself whether you think the picture is good enough and get some notion of exactly how much eyestrain is involved.
You should also find out how long it is likely to be before the set you are going to buy will become obsolete. It is not likely that reputable television set manufacturers, like those mentioned earlier, will risk public good will by offering for sale sets that may be obsolete in anything less than two years.
We haven’t talked about color television up to now because, although the authorities don’t agree, color television seems a long way off. Color television is to black and white television what technicolor is to ordinary motion pictures. It is still in the research laboratory, but one day the complex problems will be solved and you’ll be able to see telecasts in natural colors. In the meantime, black and white television will be the order of the day.
A number of methods of transmitting pictures in natural color have been demonstrated. The most recent method makes use of a whirling transparent disc in the television camera in the studio and a similar disc in the receiver at home.
Both discs are divided into three segments, one tinted red, another yellow, and the third blue. In operation, the color disc on the camera televises one picture in red, the next in yellow, and the next in blue, then it starts back with red again. The disc at the receiver end successively colors the pictures red, yellow, and blue as they are received on the screen. Persistence of vision on the part of the viewer assembles the red, blue, and yellow pictures into a completely colored image.
The big disadvantage of this method is the inconvenience of having to look through a whirling disc in order to view the color pictures.
Another method of producing color television paints the pictures electronically. The electronically painted color picture contains more than three times as many elements as the black and white picture. It blends about 900,000 tiny characters into each picture. Only 20 pictures a second can be transmitted, compared to the 30 pictures a second sent by black and white television.
Color television is definitely on the way. When it does come, it will give added realism and emotion to the television screen in addition to the new factors of warmth, life, and beauty that black and white pictures do not possess.
What is the most important thing to you in buying a television set—quality of picture, kind o f programs available, or color pictures? Surveys show that 83 per cent of the people in the United States want television sets in their homes. Is $100 too much to ask them to pay for a set? Should they be denied television until improved pictures are available? Will projection television be more popular than direct view television? Should sets be built so that you can switch from one to the other? Will the establishment of television stations in the bigger cities cause people to move in from areas where television is not available? Will color television render previously sold black and white transmitting and receiving equipment obsolete? Should television be held up until color is perfected?