medium wave
noun /ˈmiːdiəm weɪv/
  /ˈmiːdiəm weɪv/
 (abbreviation MW)
 [uncountable] (also the medium wave [singular])
- a band of radio waves with a length of between 100 and 1 000 metres, used for broadcasting
- on (the) medium wave 648 m on (the) medium wave