25-08-2015, 09:54 PM
(24-08-2015, 08:18 AM)Ian - g4jqt Wrote: ... modern AM sets (if you can still buy them!) standardised on 455 kHz across the globe.
455 x 2 = 910. When Radio Five started on 909, there were listener complaints about a 'tunable whistle'. Presumably because the station was very widely listened to on a variety of sets ...
Sorry, Ian, but you are wrong there on two counts!
Firstly, 455kHz is the US standard IF and was, therefore, adopted for all the sets made in the far east, initially for the US market. For some reason, nobody seems to have ever persuaded these manufacturers to move the IF to the European 470kHz for their exports aimed in this direction!
It has not, as far as I am aware, been adopted for use in Europe or 'globally standardised' as you put it
Secondly, this problem first became apparent long before the arrival of Radio Five when what our American friends call 'vest pocket radios' first landed on these shores in 1962!
455 x 2 = 910, as you say, and was 2kHz above the 908kHz transmissions (pre WARC-79) of the Home Service! The resultant whistle tended to go unnoticed in those days, though, as the vast majority of the users of such sets were youngsters only interested in the Light Programme and Radio Luxembourg plus, later, Radio Caroline et al ...
