Wave plan of Geneva
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The Final Acts of the Regional Administrative LF/MF Broadcasting Conference (Regions 1 and 3) Geneva, 1975 (GE75) is an internationally agreed frequency plan prepared in Geneva for radio broadcasting on the Longwave and Mediumwave bands outside of the Americas. (A separate agreement is in place for North and South America).
It was drawn up under the auspices of the World Administrative Radio Conference (WARC) of the International Telecommunications Union (ITU) with the assistance of the European Broadcasting Union (EBU/UER)
The Geneva plan replaced the 1948 Copenhagen plan. It became necessary because of the large number of broadcasting stations in these frequency ranges leading to ever more mutual interference. That Geneva wave plan entered into force on 23 November 1978 and although its intended lifespan was only until 1989 it is still valid (with small modification by mutual coordination between countries) today.
Most existing European radio stations were required to change their broadcasting frequencies following implementation of plan . In most cases the changes were slight (only one or two Kilohertz) but were more drastic in some cases, particularly in the United Kingdom. However the increased number of radio services and reduction (in most cases) of interference to radio signals (particularly at nighttime) was considered by broadcasters to be worth the initial inconvenience.
As a result of the plan most medium wave (and later Longwave) stations outside North and South America operate on exact multiples of 9 KHz which helps reduce heterodyne interference.
[edit] Predecessors to the GE75 Plan
- Geneva 1925 (Effective 14 Nov 1926) 10 KHz spacings on MW;
- Brussels 1928 (Effective 13 Jan 1929) 9 KHz spacings on MW (10KHz above 1000KHz);
- Prague 1929 (Effective 30 June 1929)"European Radio-electric Conference of Prague 1929" 9 KHz spacings on MW (10KHz above 1400KHz);
- Madrid/Lucerne 1932 (Effective 15 Jan 1934) "Lucerne Convention European Wavelength Plan" Mostly 9KHz spacings but not harmonic multiples;
- Montreaux 1939 (Was to be effective 1940 but never implemented due to WW2);
- Copenhagen 1948 (Effective 15 Mar 1950) "European LW/MW Conference Copenhagen 1948" 9KHz spacings but not harmonic multiples -offset 1 KHz on MW and 2KHz on LW.
