who discovered radio radiation?

Answer 1

Check this...

"Hertz, Heinrich Rudolf (Ger. hīn'rikh rOO'dôlf herts) [key], 1857–94, German physicist. He confirmed J. C. Maxwell's electromagnetic theory and in the course of experiments (1886–89) produced and studied electromagnetic waves (known also as hertzian waves, or radio waves). He demonstrated that these are long, transverse waves that travel at the velocity of light and can be reflected, refracted, and polarized like light. Hertz also investigated electric discharge in rarefied gases. " [See source.]

Please note that Hertz confirmed Maxwell's equations, which first predicted radio waves. So in a real sense, Maxwell first discovered radio waves by predicting them. At the very least, the equations gave Hertz something to look for.

Answer 2

Heinrich Hertz was the first to demonstrate the existence of radio waves.

Though I think that their existence may have been deduced before that. I don't know who, but maybe it was Hertz

edit: And I should have known it was Maxwell's equations that pointed him in that direction. Darn it, I'm getting rusty : )