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An antenna analyzer measuring SWR and complex impedance of a dummy load. MFJ-269, MFJ Enterprises Inc. An antenna analyzer or in British aerial analyser (also known as a noise bridge, RX bridge, SWR analyzer, or RF analyzer) is a device used for measuring the input impedance of antenna systems in radio electronics applications.
Although the same information could be obtained by measuring the load's impedance with an impedance analyzer (or "impedance bridge"), the SWR meter is simpler and more robust for this purpose. By measuring the magnitude of the impedance mismatch at the transmitter output it reveals problems due to either the antenna or the transmission line.
High winds and corrosion Senior Road Tower, Missouri City, Texas, US December 7, 1982: Guyed steel lattice mast 569 Guy support wire severed Total collapse during installation of 6-ton FM antenna on new 1800 ft. tower. Five technicians killed: two on the hoist riding the FM antenna up and three on the tower.
In telecommunications, the free-space path loss (FSPL) (also known as free-space loss, FSL) is the attenuation of radio energy between the feedpoints of two antennas that results from the combination of the receiving antenna's capture area plus the obstacle-free, line-of-sight (LoS) path through free space (usually air). [1]
A directional SWR meter measures the magnitude of the forward and reflected waves by sensing each one individually, with directional couplers. A calculation then produces the SWR. A simple directional SWR meter. Referring to the above diagram, the transmitter (TX) and antenna (ANT) terminals connect via an internal transmission line.
An antenna designer must take into account the application for the antenna when determining the gain. High-gain antennas have the advantage of longer range and better signal quality, but must be aimed carefully in a particular direction. Low-gain antennas have shorter range, but the orientation of the antenna is inconsequential.
Cross-needle SWR meter on antenna tuner. It is a common misconception that a high standing wave ratio (SWR) per se causes loss. [3] A well-adjusted ATU feeding an antenna through a low-loss line may have only a small percentage of additional loss compared with an intrinsically matched antenna, even with a high SWR (4:1, for example). [21]
An antenna control unit utilizes the resulting difference signal to select the optimum signal strength for the particular step of the search pattern. This system is particularly applicable to extremely high frequency communication channels (86 GHz and above) which are subject to atmospheric distortion and noise.