SPARK TO VALVE

Radio Record, Volume I, Issue 18, 18 November 1927, Page 16

SPARK TO VALVE

WAHINE AND MAORI The Union Steam Ship Company’s Wellington-Lyttelton ‘ferry’ steamers Wahine and Maori are now no longer a cause of interference with broadcast listening, having been equipped with valve morse-transmitters which are being used in place of the crashing, inter fering spark transmitters, The new, transmitters are proving a complete success from an operator’s point of view as well as affording relief to broadcast listeners. These vessels use a cotisiderable amount of morse for passengers’ messages while on their run between Wellington and Lyttelton, and in the past have spoilt many a broadcast item for listeners in their homes ashore. This is now a thing of the past so far as these two steamers are concerned. IN THE UNITED STATES. The work of equipping and re-equip-ping American vessels in the change from spark to valve transmitters has been going on steadily during the past two years. Already several hundred ships are equipped with valve transmit ting apparatus, or will be very shortly. Spark signals are becoming a rarity, except for the occasional small foreign ship which comes into an American port and proceeds to squat on the 450metre or 600-metre channels in unload ing its traffic amid a world of broadcast entertainment, and also a few coastal stations still operating with spark transmitters. The difference between spark and valve transmission is that the former spreads over a wide band of wavelengtfis interfering with all broadcasting more or less, according to the proximity of the spark transmitter, while the valve transmitter can be tuned as sharply as-a broadcasting station, thus eliminating interference.