AM Radio Band

The Amplitude Modulated (AM) radio carrier frequencies are in the frequency range 535-1605 kHz. The frequencies 30-535 kHz are used for maritime communication and navigation and for aircraft navigation. Carrier frequencies of 540 to 1600 kHz are assigned at 10 kHz intervals.

Short Wave

The RF frequency range around 40-50 MHz is important as the proton resonance frequency range used in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI).

TV and FM Radio Band

The carrier frequencies for VHF television Channels 2-4 cover the frequency range 54 to 72 MHz. There is a band from 72-76 MHz which is reserved for government and non-government services, including a standard aeronautical beacon at 75 MHz. VHF TV channels 5 and 6 are between 76 and 88 MHz. The FM radio band is from 88 to 108 MHz between VHF television Channels 6 and 7.Above the FM is a range 108-122 MHz for aeronautical navigation including localizers, radio ranging and airport control. From 122 to 174 MHz is another general service band for both government and non-government signals. It includes fixed and mobile units and amateur broadcast. Channels 7 through 13 span the frequency range 174-216 MHz. 216-470 MHz includes a number of fixed and mobile communication modes, including some aeronautical navigation and citizens radio. 470-890 MHz includes UHF television channels 14 to 83. Frequencies 890-3000 MHz include a variety of aeronautical and amateur uses, studio-transmitter relays, etc. There are radar bands 1,300-1,600 MHz.

The FM stations are assigned center frequencies at 200 kHz separation starting at 88.1 MHz, for a maximum of 100 stations. These FM stations have a 75 kHz maximum deviation from the center frequency, which leaves 25 kHz upper and lower "gaurd bands" to minimize interaction with the adjacent frequency band. Television channels have 5 MHz separation.

The frequency range for mobile cellular telephones is listed as 824.040 - 848.970 MHz.

Microwaves, Radar

While there are some radar bands from 1,300 to 1,600 MHz, most microwave applications fall in the range 3,000 to 30,000 MHz (3-30 GHz). Current microwave ovens operate at a nominal frequency of 2450 MHz, a band assigned by the FCC. There are also some amateur and radio navigation uses of the 3-30 GHz range. In interactions with matter, microwave radiation primarily acts to produce molecular rotation and torsion, and microwave absorption manifests itself by heat. Molecular structure information can be obtained from the analysis of molecular rotational spectra, the most precise way to determine bond lengths and angles of molecules. Microwave radiation is also used in electron spin resonance spectroscopy.

For microwave ovens and some radar applications, the microwaves are produced by magnetrons.

Of great astrophysical significance is the 3K background radiation in the universe, which is in the microwave region. It has recently been mapped with great precision by the WMAP probe.

Millimeter Waves, Telemetry