INTERFERENCE.

Auckland Star, Volume LXIV, Issue 1, 3 January 1933, Page 9

INTERFERENCE.

RADIO PROBLEM. "EXTENSIVE INVESTIGATION." EXAMPLE FROM BRITAIN. (By Telegraph.—Own Correspondent.) WELLINGTON, this day. Radio receiving licenses in New Zealand arc, in the great majority of instances, for sets capable of bringing in distant stations. But the constant handicap to "reaching out" is that, with the increase in amplification, there comes annoying interference by noises from all kinds of electrical machinery. It is a problem which most countries are tackling with vigour, owing . to the rapid development of radio broadcasting and the substantial revenues derived from listeners, whose claim for protection from extraneous noises is officially admitted. The responsibility for dealing with this question in New Zealand rests on the engineering branch of the Post and Telegraph Department, and a brief reference to its work appears, in the Departmental report: "The staff detailed for radio inspection duties has continued activity, with varying success, in connection with the elimination of interference with broadcast reception. At the close of the year extensive investigation was being made with a view to elimination of further sources of disturbance."

The British Post Office is so active in this sphere that at the recent annual radio exhibition at Olympia it staged a very comprehensive display illustrating many of the common causes of radio interference, and how to deal with them. A radio set was at work, and a lecturer called attention to the ideal conditions which should prevail. Then electric motors were started on the stand, a traffic control signal got to work, and the resultant crashes and cracklings were heard at high amplification on the radio set. Explanations were given at intervals to highly interested crowds, of the methods by which these extraneous noises could be cut out. Many household appliances were shown to be guilty, and the officials gave advice to individuals on the subject, presenting them, free of charge, with the wiring diagrams of suitable filter and choke units to eliminate noises where they originated within the sphere of their own control. Electric signs, street control signals and similar devices present a different problem, but the radio inspectors, when complaints are made regarding these causes of noise, interview the owners and offer to supply a shuitable eliminating device. In many cases they instal it on approval, with the happy result that the owner ultimately, in the public interest, provides the cost, and it becomes a permanent fitting. The pressure of public opinion is also found to be of value, as the receipt of a number of complaints is utilised by the authorities to influence the owners of offending machinery to introduce the simple elimination device designed by the Post Office, which places full technical advice and diagrams at the disposal of these individuals.