RADIO NOTES

Dominion, Volume 28, Issue 122, 16 February 1935, Page 22

RADIO NOTES

Television Still “Just Round the Corner”

“ACORN” RADIO TUBE

Practical bom® television is still “just round the corner,” according to the considered opinions of leaders in the radio industries of Great Britain and the United States. Lord Belsdoui ,of the B.B.C.,"days that the television transinievsioms of the corporation are still only experimental, and have ■®not ) by any means, been accepted by the general pub-

lic. Mr. Sarnoff, of the Radio Corporation of America, says that the development by Marconi of micro-waves has made possible a means of transmission free from static and fading, but thut.it ' is still necessary to find a satisfactory mode of flashing in a brief moment a complete picture, either moving or still. Protagonists of,fhe.cathode ray and of the mechanical scanning discs continue to dispute the merits of their respective systems, but it remains that no entirely practical and satisfactory system of transmission and home reception has yet been evolved. Lee de Forest, perfector of the radio valve, points out that even if a satisfactory system is perfected in the near future it will not come into wide usage until some mean's has b.een found of making the venture commercially profitable. Almost all of those whose opinions were sought agree that next to the grave problems in perfecting television ranks the difficulties in the way of providing regular programmes of sufficient interest to the public. .

“Acorn” Radio Tube; ■* No larger than an acorn, there is now available for experimental use on microwaves a lilliputian radio tube that may be used in either a receiver or a transmitter. In addition to being the size of an acorn the tube has the same characteristic “collar” and has accordingly been officially dubbed the “Acorn.” The tube requires 6.3 volts on its filament, has an amplification factor of 25 and requires a maximum plate voltage of 180. It !» said to function excellently on the 2% metre and lower bands and to have sufficient output when used as a transmitter' to cover readily transmission over “line of sight" distances. Networks of Stations.

Apart from the national network, at present'limited to eight or nine, stations, at the most, and the occasional combination of varying numbers of. commercial stations, network broadcasting is not of very great magnitude in Australia as yet. But in North America it is practised extensively. The largest chain is that of the Columbia Broadcasting System (U.S.A.), with 102 stations, including seven 50 kilowatt units. The National Broadcasting Company (U.S.A.), with its red and blue networks, controls 93 transmitters.,l9 of which are of 5Q kflowatt.: In Canada, 42 stations unite under the control of the Canadian Radio Commission, and the latest combination, the American Broadcasting System, ties together 25 transmitters.

“Hot News” Broadcasting. By means of a portable mircophoue attached by a cable to a motor-car, the German broadcasting authorities are able to make first-hand reports on items of news value. For instance, if a big fire breaks out, the car is rushed round and the microphone put into commission almost as soon as the fire engines arrive. Gramophone records of the reports are later broadcast in a news' bulletin.