[Utilizer]

That is the "Wavelength" function. I defy you to provide details of a standard RF transistor that can detect the ElectroMagnetic radiation of "Light".

I have five and ten gigahertz transceivers, and none of them can detect light at any frequency.

[Windcatcher]

A photodiode can of course detect light, but good luck getting any bandwidth out of it (grin). I think CD laser pickups are the way to go since they give you almost everything you need.

[E. Pluribus Unum]

You can make a transmitter and receiver that use visible light. It used to be a science project experiment with a light bulb that flickered when you spoke into the microphone and a receiver that used a photocell to convert the amplitude-modulated light waves into an electrical signal that would be amplified and output to a speaker.

But you're right. Your shortwave receiver won't pick it up, because it's tuned to a different range of frequencies.

[reed13k]

Your confusing Electromagnetic with RF. Xrays are electromagnetic that doesn’t mean your transceiver can pick it up because it isn’t tuned to the frequency in question - just like it isn’t tuned to pick up the visible light spectrum - it is all electromagnetic waves. RF is one subset of frequencies in the electromagnetic spectrum.