The number of times the polarity of an AC voltage changes per second determines its frequency.

Frequency is measured in cycles per second or Hertz (Hz).

A thousand cycles per second is a kilohertz (kHz).

One million hertz is a Megahertz (MHz).

The only difference between the 60 Hz electric power in your house and radio frequencies (RF) is the frequency, but 60 Hz electricity in a wire also produces electromagnetic radiation just like radio waves.

Useful radio waves start at 30 kHz and go upward in frequency until you reach the infrared light waves.

Light is the same kind of waves as RF except light is at a much higher frequency.

Light waves are used like radio waves when they are confined inside fiber optic cable.

Above the frequencies of light are found x-rays and gamma rays.

The radio bands: The Long Wave Band (LW) starts at 30 kHz and goes to 300 kHz.

The Medium Wave Band (MW) is from 300 kHz to 3000 kHz or 3 MHz.

The High Frequency Band (HF) is from 3 MHz to 30 MHz.

The Very High Frequency Band (VHF) is from 30 MHz to 300 MHz.

The Ultra-High Frequency Band (UHF) is from 300 MHz to 3000 MHz or 3 GHz.

Above these frequencies are several microwave bands which are defined as the Super High Frequency Band (SHF).