Sorry about the duff link, it’s
http://www.eurocontrol.int/vhf833/Do...de_english.pdf
Para 3.1.1.
Aircraft VHF radio equipment in the ICAO EUR Region will still be required to be able to tune to 25 kHz spaced channels and receive in an environment which uses offset-carrier systems (the so-called CLIMAX operation). Airspace users should take into account that these offset-carrier systems will continue to be used throughout Europe.