Line-Of-Sight Propagation
Line-of-sight propagation occurs when signals travel in a straight-line form the transmitting antenna to the receiving antenna. These signals, also know as direct waves, are used mostly in very high frequency (VHF), ultra high frequency (UHF) and microwave ranges. The signals you receive from your local television stations and FM radio stations are examples of direct waves. Two-way radios, like police and fire departments and Amateur Radio operators use, is another good example of line-of-sight propagation. When transmitting on a local repeater frequency, direct waves generally travel in a straight line to the repeater. The repeater then retransmits the signal in a straight line.