"A",
"B",
"C",
"D",
"E",
"F",
"G"/"H",
"I"/"J"/"K"/"L",
"M"/"N"/"O",
"P"/"Q",
"R",
"S",
"T",
"U"/"V"/"W"/"X"/"Y"/"Z"
Scattering: The spreading or breaking up of electromagnetic waves when they encounter objects of different electrical properties than those in which the wave is traveling.
Schmidt Antenna: A style of scanning microwave antenna.
Shortened dipole: A dipole antenna made to resonate at a lower frequency by use of a coil.
Signal: A radio wave that contains the transmitted message.
Signal loss: The amount of signal power lost between the transmitter and receiver.
Signal-to-noise ratio: [SNR] The power intensity of the signal compared to that of the noise.
Single, Stationary-Lobe System. Antenna (with a single, stationary beam) that is rotated to obtain 360-degree coverage.
Skip distance: The distances on the Earth’s surface between the points where a radio wave sky wave leaves the antenna and is successfully reflected and/or refracted back to Earth from the ionosphere. At a given azimuth, the minimum distance between the transmitting station and the closest point of return to the Earth of a transmitted wave reflected from the ionosphere.
Skip zone: The space or region within the transmission range where signals from a transmitter are not received, i.e., between the ground wave and the point where the refracted wave returns.
Sky wave: A radio wave that is reflected from the ionosphere. A radio wave that travels upward from the antenna.
Sloping long-wire antenna: A wire antenna of length greater than one wave-length and supported in an inclined orientation with respect to the ground.
Slot Antenna: A radiating element formed by a slot in a conducting surface or in the wall of a waveguide.
Spoiler Antenna: An antenna used to change (spoil) the antenna pattern of a second antenna so as to reduce the nulls in the pattern of the second antenna. See also Null Fill.
Spreader: Insulator used with transmission lines and antennas to keep the parallel wires separated.
Standing-wave: The distribution of voltage and current formed by the incident and reflected waves which have minimum and maximum points on a resultant wave that appears to stand still.
Standing-wave ratio: [SWR] The ratio of the maximum to minimum amplitudes of voltage, or current, along a transmission line.
Standing waves: Waves that appear not to be moving as the result of power traveling in both directions along a transmission line.
Stratosphere: The second layer of the Earth’s atmosphere, extending from 10 to 50 km.
Stub: Short section of a transmission line used to match the impedance of a transmission line to an antenna.
Superturnstile Antenna: A stacked antenna with radiation elements shaped like a bat-wing.
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Antenna "T" Terms and definitions
