RADIO TROUBLES

Greymouth Evening Star, 27 February 1939, Page 2

RADIO TROUBLES

WORK OF INSPECTORS. When radio broadcasting came into being, not. so many years ago, it was almost the last of the distinctive electrical developments of the present age. It had been preceded by the wide use of electric power for street lighting, tramways, domestic use and manufacturing, and the multitude of electrical appliances occasionally interfered' with full enjoyment of radio I programmes owing to the introducI tion of extraneous noises. To reduce 1 this class of interference to a minimum, and enable the radio listener to enjoy reasonably good conditions of reception, is the task of a special section of the Post Office organisation. In the work of tracing and endeavouring to remedy radio interference, the radio inspection branch of the Post Office employs staffs in twenty areas throughout the Dominion. In the smaller districts there is one officer, but in larger centres as many as three are constantly employed. The radio inspectors who deal with complaints from listeners are provided with receiving equipment in a motorvehicle and with an output meter for measuring interference levels. They also carry an assortment of filters of various types suitable for the suppression of interference caused by many kinds of electrical equipment. The filters range from those of small size suitable for use on hairdressers’ clippers, milk-shaking machines, vacuum .cleaners, and similar small appliances, all of which are capable under certain conditions of introducing into a radio programme noises which cannot be classed as having entertainment value. The inspectors also have at their disposal larger filters or chokes suitable for insertion in the leads of large generating machines. The first procedure of a radio listener who is troubled with bad reception should be to secure from the Post Office a radio interference report sheet, on which appears a. number of questions tending, if faithfully answered, to throw light on the probable cause of the trouble and enable the radio inspector to effectively suppress its cause.

Radio interference is a decreasing factor in connection with broadcasting, this being proved by the fact that, although the inspectors are dealing with approximately 3000 complaints every year, this total has remained steady while receiving licenses have actually doubled since March, 1035. Official experience regarding interference troubles show that approximately 25 per cent, of complaints received by the Department originate through faulty receiving sets, and, it the faulty aerials and earthing systems are included, the percentage is much higher. The remedy in these cases comes within the listener’s province. for the Department must leave to radio servicing establishments any overhauls needed as the result of reduced efficiency of private receiving sets.

It will be noted that the larger percentage of complaints relates to interference originating outside the listener’s receiving set, and officials of the Post Office enjoy the most complete co-operation of public authorities responsible for power lines, tramway and other equipment which may be the subject, of complaint. The reporting of faulty insulators on hightension power-lines may originate from a radio listener, and remedying the fault not only satisfies the listener but saves the power authority some loss of current. It. is impossible to cure every sort of interference. Static, for instance, is still an nnsolvable problem for the radio engineer, while high-tension electric power-lines may cause an objectionable “frying” noise in receivers operated in their vicinity. This noise is not due to any electrical fault, but is inherent, in the system. '1 he operation of power-lines cannot be discontinued, so the only practicable method for I be radio listener who is prejudiced by this class of noise is to use one of the many efficient noise i euucing aerial systems and ■ mains filters. Thousands of cases are successfully treated by the radio inspectors every year.