UHF is short for ultra high frequency. It names a band of radio waves — roughly 300 to 3000 megahertz. Because the waves are short, they carry a lot of information, so the sound and picture come through clean and clear. This is the band most old broadcast TV channels sat on, and it is also where walkie-talkies, taxi radios, airport radios, cordless phones, and most modern phone signals live. You will see it written on the back of an old TV or a radio set, next to VHF (very high frequency), which is the band below it. One thing worth knowing: UHF waves travel in more or less a straight line and do not bend well around hills or buildings, so you need to be fairly near a tower, but inside a city they slip through walls better than VHF does. In ordinary talk almost nobody says the full words — engineers, radio hobbyists, and people setting up antennas just say the three letters, U-H-F, said one letter at a time.