short wave 
noun
1A radio wave of a wavelength between about 10 and 100 m (and a frequency of about 3 to 30 MHz): [as modifier]: a short-wave transmitter
1.1 [mass noun] Broadcasting using radio waves of between 10 and 100 m wavelength: [as modifier]: short-wave radio...
- Everything was censored and she relied on the BBC, broadcast through her short-wave radio, for real news from the outside world.
- All Church Services from Ballina-Boher parish are broadcast on short-wave radio.
- I was lying in my tent and heard the news on my short-wave radio from the BBC World Service.