In telecommunication, a propagation path obstruction is a man-made or natural physical feature that lies near enough to a radio path to cause a measurable effect on path loss, exclusive of reflection effects. An obstruction may lie to the side, above, or below the path. Ridges, bridges, cliffs, buildings, and trees are examples of obstructions. If the clearance from the nearest anticipated path position, over the expected range of Earth radius k-factor, exceeds 0.6 of the first Fresnel zone radius, the feature is not normally considered an obstruction.
Famous quotes containing the words path and/or obstruction:
“Today brings the sad, glad tidings that Mrs. Abraham Lincoln has passed from that darkness which had fallen upon her path through this life, out into the light and joy of that life toward which her vision has so long been strained.
Modern education is lethal to children.... We stuff them with mathematics, we pummel them with science, and we use them up before their time.”
—Honoré De Balzac (1799–1850)
“The short lesson that comes out of long experience in political agitation is something like this: all the motive power in all of these movements is the instinct of religious feeling. All the obstruction comes from attempting to rely on anything else. Conciliation is the enemy.”
—John Jay Chapman (1862–1933)