Geneva Frequency Plan of 1975

The plan was drawn up under the auspices of the World Administrative Radio Conference (WARC) of the International Telecommunication Union (ITU) with the assistance of the European Broadcasting Union (EBU/UER).

It became necessary because of the large number of broadcasting stations in these frequency ranges leading to ever more mutual interference (many countries had refused to ratify the Copenhagen plan[1] and compliance was patchy even among those which had).

The Geneva plan entered into force on 23 November 1978 and although its intended lifespan was only until 1989,[2] it is still valid (with small modification by mutual coordination between countries) today, and compliance has been far more widespread.

Most existing European radio stations were required to change their broadcasting frequencies following implementation of the plan.

As a result of the plan most mediumwave (and later longwave) stations outside North and South America operate on exact multiples of 9 kHz; the sum of all digits of the frequency will be 9 or a multiple of 9 (see 9#Mathematics).