How Do Antennas Isolate Specific Frequencies Amidst a Spectrum of Signals?

[toneboy1]

Hi, I have been researching antennas all day but I can't figure out how specifically they work in that; they seem to oscillate AC through like a band-pass filter (LC circuit) to get a signal. I'm assuming there is some sort of current 'sloshing' in and out of the antenna as they do. Also that they are most efficient at some fraction if not the full wavelength of the desired signal.
BUT what I can't figure out is you've got an AM radio that can pick up, say, 40 frequencies (stations) and the same aerial could be used for FM just as well (much smaller frequencies).
SO the electrons on the surface must be resonating with the full spectrum of AM and FM, how could you still get any ONE signal tuned in with the circuit with those electrons jostling about from an infinite amount of frequencies? Sounds like a mess.
Also, if anyone is inclined I was wondering if two EM waves of the same freq could add via superposition on the same electron to become ionizing (if each wave was say just below UV), or what's the case there? E = hf would indicate no, but I don't see where the energy would go (thinking of mechanical waves).
THANKS! (this is my first time)

 

[BigJDubs]

Antennas work by converting electromagnetic radiation in the form of radio waves into electrical signals. Radio waves are a type of electromagnetic radiation, and they consist of oscillating electric and magnetic fields. When an antenna is exposed to these radio waves, it induces an electric current that can be used to transmit and receive signals.The antenna is designed to be most efficient at certain frequencies, which can be tuned by adjusting the shape and size of the antenna. This tuning allows it to pick up specific frequencies more effectively than others, which is why the same antenna can be used for both AM and FM radio.When the antenna is exposed to a particular frequency, the electrons on its surface oscillate in resonance with that frequency. This resonance allows the antenna to capture only that frequency, while the other frequencies are filtered out. This is how the antenna is able to select one frequency from the many that are present in the air.As for your second question, two EM waves of the same frequency will not add to become ionizing, as the energy of the waves alone is not enough to ionize atoms. The energy required to ionize atoms comes from the absorbed energy of the EM wave, not from the wave itself.