Definition
The radio frequency band from 300 megahertz (MHz) to 3,000 MHz (3 gigahertz). In aviation, UHF is used primarily by military aircraft for air-to-ground and air-to-air voice communication, and by certain navigation aids such as the glide slope portion of an ILS and DME equipment.
Plain English
A specific range of radio frequencies higher than the VHF band that civilian pilots normally talk on. UHF is mostly used by the military for radio calls, and by parts of the instrument landing system and distance-measuring equipment.
Context Anchor
Seen in aviation radio, navigation, and military communication discussions.
Derivation
From Latin 'ultra' meaning 'beyond,' plus 'high frequency.' The name simply marks this band as sitting beyond the high-frequency and very-high-frequency ranges on the radio spectrum.
Why Pilots Care
Civil pilots usually transmit on VHF, but knowing that UHF exists matters when operating near military airfields, using DME, or flying an ILS approach — the glide slope signal you ride down is actually a UHF signal even though you tuned it on a VHF localizer frequency.
Intuition Check
“Ultrahigh” does not just mean “extremely high” in a general way. Here it names a fixed radio frequency band: 300 to 3,000 megahertz.
Example Sentence 1
The military controller asked the flight to switch to a UHF frequency for the handoff.
Example Sentence 2
Ultrahigh frequency equipment allows direct contact with certain ATC facilities that do not monitor VHF.