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Voltage standing wave ratio (VSWR) (pronounced "vizwar" [1][2]) is the ratio of maximum to minimum voltage on a transmission line . For example, a VSWR of 1.2 means a peak voltage 1.2 times the minimum voltage along that line, if the line is at least one half wavelength long. A SWR can be also defined as the ratio of the maximum amplitude to ...
For example, the SWR bandwidth is typically determined by measuring the frequency range where the SWR is less than 2:1 . Another frequently used value for determining bandwidth for resonant antennas is the −3 dB return loss value, since loss due to SWR is −10·log 10 (2÷1) = −3.01000 dB.
A standing wave ratio meter, SWR meter, ISWR meter (current " I " SWR), or VSWR meter (voltage SWR) measures the standing wave ratio (SWR) in a transmission line. [a] The meter indirectly measures the degree of mismatch between a transmission line and its load (usually an antenna). Electronics technicians use it to adjust radio transmitters and ...
The J-pole antenna is an end-fed omnidirectional half-wave antenna that is matched to the feedline by a shorted quarter-wave parallel transmission line stub. [5] [1] [6] For a transmitting antenna to operate efficiently, absorbing all the power provided by its feedline, the antenna must be impedance matched to the line; it must have a resistance equal to the feedline's characteristic impedance.
Height above average terrain (HAAT), or (less popularly) effective height above average terrain (EHAAT), is the vertical position of an antenna site above the surrounding landscape. HAAT is used extensively in FM radio and television , as it is more important than effective radiated power (ERP) in determining the range of broadcasts ( VHF and ...
The discone antenna has a useful frequency range of at least 10 to 1. [2] [3] When employed as a transmitting antenna, it is often less efficient than an antenna designed for a more limited frequency range. SWR (standing wave ratio) is typically 1.5:1 or less over several octaves of frequency. [4]
He traveled to Japan for a “temporary” work assignment back in 1992, and Dave Prucha, from the US, was enthralled with the East Asian country that he ended up staying for good.
Effective height. In telecommunications, the effective height of an antenna is the height of the antenna's center of radiation above the ground. In low- frequency applications involving loaded or nonloaded vertical antennas, the effective height is the moment of the current distribution in the vertical section, divided by the input current.