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I've heard many times said as an argument in favor of broadcast regulations that the radio wave medium (the atmosphere/ground) will become "polluted" if people send radio signals at whatever frequency and power they want. The signals might also cause "interference".

First, what is meant by signal pollution and interference? Do they mean the same? I think "interference" of signals can not mean that signals are colliding because radio waves pass through each other. Does it mean that electronic equipment is affected?

Second, if radio wave interference or pollution is the reason behind radio broadcasting regulations, how is this interference or pollution a problem with radio wave receivers? A radio wave receiver is tuned to a specific wave frequency, so should it not just ignore signals of other frequencies that aren't meant for it?

Thanks for reading.

Arundel
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A radio wave receiver is tuned to a specific wave frequency, so should it not just ignore signals of other frequencies that aren't meant for it?

In order for a radio signal to carry information, it can't be just a single frequency. It must carry power over a range of frequencies. You can get some background on why this is so if you research the modulation property of the Fourier transform and the Shannon-Hartley theorem. Another question on the site addressing this is, Why is bandwidth, range of frequencies, important when sending wave signals, such as in radio?

Since useful signals need a non-zero bandwidth, you can't pack an infinite number of them into a finite bandwidth without them overlapping. Also, it measn when you tune your receiver to a specific frequency it must also pick up a band of frequencies around that center frequency in order to receive any useful information (like an audio waveform or the digital data carried over a wifi link).

If two signals overlap in their frequency spectra, then when you tune your receiver to one of them, you'll hear some artifacts or noise caused by the other overlapping signal. This is what is meant by interference.

Pollution isn't a technical term like interference. In the context that you described I'd take it to mean the effects of multiple interference sources when combined together.

The Photon
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