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RadioShack (formerly written as Radio Shack) is an American electronics retailer that was established in 1921 as an amateur radio mail-order business. Its original parent company, Radio Shack Corporation, was purchased by Tandy Corporation in 1962, shifting its focus from radio equipment to hobbyist electronic components sold in retail stores.
An SWR meter does not measure the actual impedance of a load (the resistance and reactance), but only the mismatch ratio. To measure the actual impedance requires an antenna analyzer or other similar RF measuring device. For accurate readings, the SWR meter itself must also match the line's impedance (typically 50 or 75 Ohms).
In radio engineering and telecommunications, standing wave ratio (SWR) is a measure of impedance matching of loads to the characteristic impedance of a transmission line or waveguide. Impedance mismatches result in standing waves along the transmission line, and SWR is defined as the ratio of the partial standing wave 's amplitude at an ...
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 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.
When measuring with a field strength meter it is important to use a calibrated antenna such as the standard antenna supplied with the meter. For precision measurements the antenna must be at a standard height. A value of standard height frequently employed for VHF and UHF measurements is 10 metres (33 ft).
Their TRS-80 (1977) and TRS-80 Color Computer ("CoCo") (1980) line of home computers were popular in the years before the IBM PC became commonplace, and had wide distribution in Radio Shack stores at a time when there were few computer stores. Tandy had 60 Radio Shack Computer Centers by 1980, and expected to have 250 Radio Shack stores that ...
With fewer than 100 stores, far fewer than the aggressively expanding Radio Shack's thousands of local outlets, Lafayette Radio remained more of a dedicated enthusiasts' store than a mass marketer. The company was also hurt by the advent of electronics retailers relying on aggressive marketing techniques and competitive pricing in the late 1970s.