EMPIRE WIRELESS

Press, Volume LXIII, Issue 19163, 21 November 1927, Page 11

EMPIRE WIRELESS

POLICY OF THE 8.8.C. SATISFACTORY PROGRESS. (FBOSt OL-B, OWN COBBESPOXDEKT.) LONDON, October 4. An official statement has been made by tho British Broadcasting Corporation in regard to Empire broadcasting- . , In pursuance of its policy ot developing a practical basis for effective Empire broadcasting as rapidly as possible (it is stated) the 8.8.C. has now reached a stage at which it is possible to give an interim report. As has been explained already on several occasions, the problem of effective Lmpire broadcasting is as much one of reception as of transmission, and is more involved in the linking of broadcasting systems than in the provision of sporadic technical entertainment for comparatively few amateurs. The experiments now under review are being conducted by the 8.8.C. in cooperation with the Marconi Company. An experimental short-wave transmitter is being erected at the Marconi Works at Chelmsford. This will make use of the two 480 ft masts which are situated there. The transmitter will carry out experiments working chiefly on a wave-length of 24 metres. Arrangements have been made for ''he collection, collation, and analysis of _ reports of these experiments in various parts of the world. This experimental station, -whose call-sign is SSW, will transmit using power up to about '25 kw. Should its performance b«» unexpectedly successful in the early stages, programmes may be transmitted; but it is not anticipated that this exparimental station will undertake a regular service. Experiments in Reception. Satisfactory progress is being made with experiments in reception by the use of what has come to be known as the "spaced aerial" method. The chief difficulty experienced hitherto in the reception of ultra short wave transmission is due to the phenomenon known as "fading." It is believed that the reception of transmissions on ultra nhort waves is made possible entirely through reflection. Unfortunately, considerable changes are taking place continually in the reflecting medium. The result'is that the strength of signals received at any given point is constantly varying. In the case of _ extended transmissions, the variations 'take place so rapidly and with such confusion that they are apt to exercise a disastrous effect upon reception. All experienced and competent engineers now realise that the success of Empire broadcasting depends mainly upon the possibility of transmissions being re-radiated efficiently by local broadcasting stations. It is, therefore, essential to devise a method of reception which will minimise the fading effect. Experiments indicate that the signals from two or more aerials spaced at considerable distances a; art may be combined and treated in such a way as to produce a more constant and undistorted signal. Taking into account the results of its last series of experiments, the 8.8.C. sees no reason to revise its prediction that Empire broadcasting may be undertaken with the guarantee of the elementary conditions pre-requi-site to service some time during 1928. Contact is being maintained and developed with the broadcasting organisations of the Dominions and Colonies. The chief engineer, now attending tho World Wireless Conference at Washington, is evolving a further series of experiments in co-operation with trie chief engineer of the Radio Corporation of America. An account of this new series of experiments will be available shortly.