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:
“Another danger is imminent: A contested result. And we have no such means for its decision as ought to be provided by law. This must be attended to hereafter.... If a contest comes now it may lead to a conflict of arms. I can only try to do my duty to my countrymen in that case. I shall let no personal ambition turn me from the path of duty. Bloodshed and civil war must be averted if possible. If forced to fight, I have no fears from lack of courage or firmness.”
—Rutherford Birchard Hayes (1822–1893)
“Every obstruction of the course of justice,—is a door opened to betray society, and bereave us of those blessings which it has in view.... It is a strange way of doing honour to God, to screen actions which are a disgrace to humanity.”
—Laurence Sterne (1713–1768)