I'm an electrical engineering undergrad and have some questions about radio antennas. We've just covered the electronics and maths of radio theory once the signal has reached the receiver, I'm unclear about how the signal actually travels and its effects.
I believe (crudely, no doubt) that as an electron is moved within the transmitting antenna it creates waves in the electric & magnetic fields which, upon interacting with the receiving antenna, creates a voltage which is ultimately demodulated back to the original signal.
Before radio was invented, I imagine the electric/magnetic fields to be calmly doing their thing and to be relatively calm (or in a naturally occurring turbulent state).
Now that we transmit radio, TV & everything else, does this mean that the electromagnetic field is in constant turbulence, with numerous waves at different frequencies superimposed over the natural state?
Does this also mean that everything around us (fence posts, cutlery, cars etc) is also having voltages induced in it at the broadcast frequencies? I am aware of antennas having a resonant frequency, is it that all other objects have a sufficient highly impedance as they are not at resonance that this voltage is negligible?
Are there any tangible side-effects from this increased level of energy in the electromagnetic field since transmission began?
As these waves in the electromagnetic field are being absorbed (by everything, not just antennas) does this mean the energy of the wave is continually being reduced, and if this is the case how can we broadcast over such distances?