Filters are not magic. They have tradeoffs. If you make a filter with a really sharp cutoff you end up with a really large filter with a lot of loss. So then yo

Filters are not magic. They have tradeoffs. If you make a filter with a really sharp cutoff you end up with a really large filter with a lot of loss. So then you have trouble receiving really weak signals, say, reflections from the ground. One way you might overcome this is to really ramp up the transmitted power but that can cause radar receiver problems and can cause interference with services in adjacent bands, say, 5G. This sort of thing is why allocating TV frequencies is and was complicated. That is because someone might live right next door to a TV transmitter and they might be trying to watch a weak signal on an adjacent channel. You usually have to allocate some dead channels for the area to prevent receivers from being overloaded. So in that case would it be fair to say that receiver was using channels it had no right to when set to the weaker signal? After all, the transmitter was there before the receiver was... Note that other countries have managed to deal with this routine and common issue with respect to the introduction of 4 GHz 5G. There is something weird going on in the USA...