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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.
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.
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.
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]
An SWR meter for CB radio equipment. 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).
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 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.
The high reactance vs the low resistance give the antenna a high Q factor; the antenna and coil act as a high Q tuned circuit, reducing the usable bandwidth of the antenna. At lower frequencies mast radiators are replaced by more elaborate capacitively toploaded antennas such as the T antenna or umbrella antenna which can have higher efficiency.