Wireless Broadcast Systems Research Articles

Low Power Radio Transmitters for Broadcasting

This paper discusses the place of low powered installations in the existing radio broadcast system, and the importance of apparatus for such stations meeting the present-day requirements pertaining to frequency stability, modulation capability, fidelity, and radio-frequency harmonics. The characteristics and more interesting features of a new line of transmitters covering the range of output from 100 to 1000 watts are described. The basic unit is a 100-watt transmitter employing grid-bias modulation which is novel in so far as American broadcast practice is concerned. Outputs of 250, 500, and 1000 watts are obtained through the use of a supplementary amplifier unit equipped with tubes of appropriate capacity. Radiation-cooled tubes are used throughout, and both units are self-contained, being operated direct from an alternating-current supply without the use of rotating machinery. Mechanically the units are novel in that the housings are of a cabinet form with doors which allow complete access from the front for adjustment and maintenance.

Experimental Results on a Radio Broadcasting System Using Distribution Networks of Electric Supply

Experimental Results on a Radio Broadcasting System Using Distribution Networks of Electric Supply

Long Distance Cable Circuit for Program Transmission

The rapid growth of the telephone cable network in this country has made it desirable to develop a system whereby this network may be utilized to transmit programs for broadcasting stations over distances upwards of 2000 miles. Such a system has recently been developed and given a trial on a looped-back circuit 2200 miles long with very satisfactory results. It transmits ranges of frequency and volume somewhat in excess of those now handled by the open-wire circuits which are used for program work, and also in excess of those handled by present-day radio broadcasting systems when no long distance lines are involved. The paper deals first with the transmission requirements of broadcasting systems and then gives a description of this new cable system.

Abridgment of long distance cable circuit for program transmission

The rapid growth of the telephone cable network in this country has made it desirable to develop a system whereby this network may be utilized to transmit programs for broadcasting stations over distances upwards of 2000 mi. Such a system has recently been developed and given a trial with very satisfactory results on a looped-back circuit 2200 mi. long. It transmits ranges of frequency and volume somewhat in excess of those now handled by the open-wire circuits which are used for program work, and also in excess of those handled by present-day radio broadcasting systems when no long distance lines are involved. The paper deals first with the transmission requirements of broadcasting systems and then gives a description of this new cable system.

Long Distance Cable Circuit for Program Transmission*

The rapid growth of the telephone cable network in this country has made it desirable to develop a system whereby this network may be utilized to transmit programs for broadcasting stations over distances upwards of 2,000 miles. Such a system has recently been developed and given a trial on a looped-back circuit 2,200 miles long with very satisfactory results. It transmits ranges of frequency and volume somewhat in excess of those now handled by the open-wire circuits which are used for program work, and also in excess of those handled by present-day radio broadcasting systems when no long distance lines are involved. The paper deals first with the transmission requirements of broadcasting systems and then gives a description of this new cable system.