All radios, including two-way radios, make use of an antenna to transmit or receive information over the air to and from other radio stations and people. The best results and longest distances are usually achieved by using an external antenna mounted on a vehicle, a building or other support that gives more height. In many radios that use UHF or higher frequencies, the antenna may be internal and too small to see; and other antennas can range in size from a few inches several feet. Some HF (shortwave) radio signals may need antennas that are tens or even hundreds of feet long.