An integrated circuit containing analog circuitry operating at frequencies in and above the ultrahigh frequency band.

The transmission of speech using modulated radio waves

(dated) A small portable radio receiver having transistors rather than thermionic valves; popular from the late 1950s.

(idiomatic) Unlikely to happen or be important in the near future, or tending to escape detection or attention.

(idiomatic) Without attracting notice; in an undetected or secretive manner.

Synonym of crystal set

High-energy radiation that is capable of causing ionization in substances through which it passes; also includes high-energy particles.

(chiefly Britain, informal) Radio (sound broadcasting), considered as old-fashioned compared to television.

(astronomy, physics) Either of two torus-shaped areas of high-energy charged particles which partly surround Earth, trapped by its magnetic field. The areas are characterised by intense radiation. When the belts "overload", particles strike the upper atmosphere and fluoresce, causing the polar aurora.

(astronomy) A device for observing astronomical sources of radio waves, normally having one or more large parabolic dishes.