If there are lots of different radio signals with the same or very similar wavelengths, how is it possible for a radio to pick up just one signal?
In: Technology
It isn’t. If two stations in the same area broadcast with too similar frequency they will interfere. This is why a radio station needs to apply to a state authority to get assigned a frequency, and the state agency has to make sure that there is always enough spacing between frequencies assigned to stations in the same area.
Having an assigned frequency is hence a big thing, and there is a lot of fighting and hassling for frequencies.
Things get more complicated with things like cell phones. Your phone will always stay in contact with the nearest cell tower, and that cell tower will communicate with many phones using the same frequency. That only works if the phones don’t transmit simultaneously. Hence, the tower tells each phone when it is allowed to send, switching from phone to phone many hundred times each second. The phones digitally compress the speech so that they can transmit, say, 10 millisecond of speech in their time slice even if that slice is only one millisecond long.
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