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:
“The path was a vague parting in the grass
That led us to a weathered windowsill.
We pressed our faces to the pane. “You see,” he said,
“Everything’s as she left it when she died....””
—Robert Frost (1874–1963)
“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)