Common radio frequency bands include the following:
- AM radio - 535 kilohertz to 1.7 megahertz
- Short wave radio - bands from 5.9 megahertz to 26.1 megahertz
- Citizens band (CB) radio - 26.96 megahertz to 27.41 megahertz
- Television stations - 54 to 88 megahertz for channels 2 through 6
- FM radio - 88 megahertz to 108 megahertz
- Television stations - 174 to 220 megahertz for channels 7 through 13
What is funny is that every wireless technology you can imagine has its own little band. There are hundreds of them! For example:
- Garage door openers, alarm systems, etc. - Around 40 megahertz
- Standard cordless phones: Bands from 40 to 50 megahertz
- Baby monitors: 49 megahertz
- Radio controlled airplanes: Around 72 megahertz, which is different from...
- Radio controlled cars: Around 75 megahertz
- Wildlife tracking collars: 215 to 220 megahertz
- MIR space station: 145 megahertz and 437 megahertz
- Cell phones: 824 to 849 megahertz
- New 900-MHz cordless phones: Obviously around 900 megahertz!
- Air traffic control radar: 960 to 1,215 megahertz
- Global Positioning System: 1,227 and 1,575 megahertz
- Deep space radio communications: 2290 megahertz to 2300 megahertz
Why is AM radio in a band at 550 kilohertz to 1,700 kilohertz, while FM radio is in a band at 88 to 108 megahertz? It is all completely arbitrary, and a lot of it has to do with history.
AM radio has been around a lot longer than FM radio. The first radio broadcasts occurred in 1906 or so, and frequency allocation for AM radio occurred during the 1920s (The predecessor to the FCC was established by Congress in 1927.). In the 1920s, radio and electronic capabilities were fairly limited, hence the relatively low frequencies for AM radio.
Television stations were pretty much non-existent until 1946 or so, which is when the FCC allocated commercial broadcast bands for TV. By 1949, a million people owned TV sets, and by 1951 there were 10 million TVs in America.
FM radio was invented by a man named Edwin Armstrong in order to make high-fidelity (and static-free) music broadcasting possible. He built the first station in 1939, but FM did not become really popular until the 1960s. Hence the higher frequencies for FM radio.