When it comes to radio, voice takes a lot more bandwidth than digital signals[1]. This has important practical implications. A typical voice signal takes abou

When it comes to radio, voice takes a lot more bandwidth than digital signals[1]. This has important practical implications. A typical voice signal takes about 3kHz of bandwidth, whereas a CW (continuous wave, Morse code signal) can be done in about 500Hz. The lower bandwidth lets you pack all of your transmitter power into that tiny little bandwidth, and get your signal out that much further than the same power would give you with voice. Also, when receiving, you can narrow your receiver down to just the tiny little bandwidth window you're looking at, and ignore everything higher and lower, leading to less interference. These are the key reasons why Morse code is still alive and well today. Other digital modes exist that give you almost the same kinds of benefits as CW for very low bandwidth, most notably PSK31. [1] Technically, the speed of the signal switching causes you to need more bandwidth. So if you're doing a really fast digital transmission, like a 56k modem, that requires more bandwidth than a 9600 baud modem transmission. This makes intuitive sense. What's kinda surprising though is that even really fast morse code requires more bandwidth that slow morse code.