Line of Sight Propagation

  • Free space attenuation results from signal radiating outward in all directions
  • Signal power weakens with the square of the distance travelled – double the distance signal power drops by a factor of four (inverse square law).  Doubling distance halves signal voltage
  • Line of sight propagation (normal mode at VHF/UHF) approximates the free space model
  • Limit of line of sight is known as the radio horizon, which increases as antenna height increases