Definition
A unit of frequency equal to one million cycles per second. In aviation it is most often used to describe radio frequencies for voice communication and navigation.
Plain English
It is a way of measuring how fast a radio signal vibrates. One MHz means the signal completes one million back-and-forth cycles every second.
Context Anchor
Seen when tuning aircraft radios, reading maintenance information for antennas and aircraft electronics, or checking the frequency range of installed equipment.
Derivation
From 'mega' (Greek for 'great' or 'large', used in science to mean one million) and 'hertz', named after Heinrich Hertz, a German physicist who proved radio waves exist. So megahertz literally means 'a million hertz' — a million cycles per second.
Why Pilots Care
Aviation radios and navigation aids operate on specific MHz frequencies. Tuning the wrong frequency means missed calls, lost guidance, or being on the wrong channel during a critical moment.
Analogy
Think of MHz like an address on a radio dial. The number tells the radio exactly where to listen or transmit.
Intuition Check
MHz is not a measure of volume, range, or signal strength. It is a measure of frequency: how many times the wave repeats each second.
Example Sentence 1
The pilot tuned the standby radio to 122.8 MHz to monitor the local traffic frequency.
Example Sentence 2
VOR navigation signals are transmitted between 108 and 118 MHz.