When we talk about radio we automatically think of those stations that are run on analog signal waves. And there's nothing wrong with that, it's actually been around a long time. But as we become more educated about radio and what it can do, we've also begun to realize that FM radio isn't perfect. It wasn't designed to be. There are some serious limitations and drawbacks to FM radio.
For instance, if you wanted to send a signal to someone in another country, or even a different city, there was only one way to do it, and that was by using long distance carriers. And even then, not all of those signals were equal. The strength of FM radio is actually determined by the power of the transmitter, and it has nothing to do with the quality of the reception. It is simply the strength of the transmitted signal.
But there are other limitations as well, and they all come from how the system is regulated. With AM radio, there is a carrier wave, and this wave changes in frequency over a fixed period of time. If you want to send something at a certain time, you just set the date and time you want the transmission, and then wait for the transmission to happen. Once it happens, you hear it!
However, the problem is that fm stations transmit their radio waves in a fixed (known as "fect" or "fade" wave) along with the rest of their signal. So all of their audio information is chopped up into a bunch of little "bitty bits". Each of these bits has an amplitude which is a very small amplitude within the complete range of their average frequency. Now imagine sending a long wave radio signal with a much lower amplitude through a narrow frequency band. That's not going to do what you want it to do. That's because you're talking about sound quality, and not about aesthetics.
So now you have to figure out how to convert your fm signal to a carrier frequency modulation, and send that signal on a much longer wire. That's why AM radio operators use what are called "discovery bands" to send their discovery information. These discovery bands are separated into groups, and then the radio operators can send their info out over these bands. This is a great way to increase your chances of getting a good reception.
Carrier frequency modulation, on the other hand, converts your fm signal into the same type of signal used in telecommunication. Then you can adjust your radio's settings so that it will convert your fm signal into that signal! And there is even more to this, but that's another article for another time. For now, let me leave you with some important tips: if you don't know the difference between a carrier and a modulation, and you really care about good reception, you must get a fm radio.