Who he? I say but I am sure that the SAs among you already know the answer to that question.....he is, of course, the German physicist who clarified and expanded the electromagnetic theory of light that had been put forth by James Clerk Maxwell He conclusively proved the existence of electromagnetic waves by making instruments to transmit and receive radio pulses using experimental processes that excluded all other known wireless phenomena.
Oh, so that's alright then.
But I bet he didn't know who sent the light in the first place.
* A Wiki note, Hertz's father converted to Catholicism from Judaism.
Young Heinrich, unaccountably, became a Lutheran before snuffing it at the tender age of 36. RIP.