Line of Sight Propagation

From HFUnderground

Line of sight propagation or LOS is the primary form of VHF/UHF/SHF frequencies but can be (and often is) the primary form of propagation for land mobile two-way radio systems operating in the high HF region (broadly 24-30 MHz or so, usually 25-30 MHz, i.e. the 11 meter band and the various 26 MHz/27 MHz CB allocations worldwide.