SYDNEY LISTENERS COMPLAIN

Evening Star, Issue 22881, 12 February 1938, Page 4

SYDNEY LISTENERS COMPLAIN

INTERFERENCE WITH 2RA PROGRAMMES Many radio listeners in Sydney are complaining that they find it impossible to tune their receiving sets to the transmissions from 2KA (Katoomba) because the signals are rendered inaudible ■ by messages sent from the police radio station at Redfern to police wireless cars patrolling in various parts of Sydney. Radio experts say that the trouble is due to the particular numerical relationships between the frequencies of the two stations, and the intermediate frequency used within the affected receivers. The degree of interference is determined by the ability of a receiver to reject all signals other than those to which it is tuned. No trouble will be experienced with receivers of good design, and those of poor design can be improved by increasing their ability to reject unwanted' signals, or bv varying the value of their intermediate frequencies. _ Police wireless officials state that the messages sent from Redfern for the patrol ears arq usuallv urgent calls. The messages are oral and are not confidential. Listeners to other stations have also reported that they had picked up police messages, but most complaints came from the district round the transmitting station at Redfern.