Definition
Two adjacent bands of the radio frequency spectrum used in aviation. VHF covers 30 to 300 megahertz (MHz) and is used for civil air-to-ground voice communication (118.000–136.975 MHz) and for navigation aids such as VOR and ILS localizers. UHF covers 300 to 3,000 MHz and is used primarily for military air-to-ground voice communication and for navigation components such as the glideslope portion of an ILS and DME. Both bands are line-of-sight, meaning the signal travels in a straight line and is generally blocked by terrain or the curvature of the Earth.
Plain English
Two ranges of radio waves used in flying. VHF is the range most civilian pilots talk on and use for many navigation signals. UHF is a higher range used mostly by the military and for some parts of instrument approach systems. Both only work when the aircraft has a clear straight path to the ground station.
Context Anchor
Seen in instrument flying when describing the radio signals used by navigation aids and aircraft receivers.
Derivation
‘Frequency’ refers to how many radio wave cycles pass a point each second, measured in hertz. ‘Very High’ and ‘Ultra High’ simply describe where these bands sit on the radio spectrum — VHF was named first, and UHF sits just above it. The names are practical labels, not absolute rankings.
Why Pilots Care
These bands determine signal range, reliability, and which cockpit receivers can capture navigation information.
Grounding Statement
VHF/UHF signals are invisible radio signals sent through the air between ground equipment and aircraft equipment.
Intuition Check
VHF/UHF does not mean the signal is automatically stronger or better. It means the signal is in a particular radio frequency range.
Example Sentence 1
The pilot tuned the VHF radio to 124.5 MHz to contact approach control.
Example Sentence 2
DME equipment uses a UHF signal to calculate the slant-range distance to the transponder.