Definition
A unit of frequency equal to one million cycles per second (1,000,000 Hz). Used in aviation to express the frequencies of radio communication and navigation equipment.
Plain English
A way of measuring how fast a radio signal vibrates. One MHz means the signal completes one million cycles every second. Aviation radios are tuned in MHz.
Context Anchor
Seen when tuning aircraft communication radios, navigation receivers, approach charts, airport information, and air traffic control instructions.
Derivation
From 'mega-' (Greek megas, meaning 'great' or 'large'), used in science to mean one million, plus 'hertz', named after Heinrich Hertz, the 19th-century physicist who proved radio waves exist. So megahertz literally means 'a million hertz' — a million cycles per second.
Why Pilots Care
Pilots use MHz to tune communication radios and navigation aids such as VOR and ILS.
Intuition Check
MHz is not the name of a station or controller. It is the unit used to measure the frequency you tune on the radio.
Example Sentence 1
Example Sentence 2
Tune the VHF radio to 121.5 MHz to monitor the emergency frequency.