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Hallicrafters founder William J. Halligan depicted in a 1944 magazine ad. William J. Halligan (1898–1992), founded Hallicrafters Company in Chicago in late 1932. Prior to this, he had been involved in radio parts sales for some years but decided the time was right for a handcrafted amateur radio receiver - the company name being a combination of Halli(gan) and (hand)crafters.
Other radios from other Chinese manufacturers have mainly the same range of functions, specs and menu like the UV-5R, for example the Retevis RT5. [ 7 ] The UV-5R has attracted the attention of multiple telecommunications regulators due to problems relating primarily to frequency interference and is banned from sale and use in Switzerland ...
Vintage amateur radio is a subset of amateur radio hobby where enthusiasts collect, restore, preserve, build, and operate amateur radio equipment from bygone years, such as those using vacuum tube technology.
An amateur radio propagation beacon is a radio beacon, whose purpose is the investigation of the propagation of radio signals. Most radio propagation beacons use amateur radio frequencies. They can be found on LF, MF, HF, VHF, UHF, and microwave frequencies. Microwave beacons are also used as signal sources to test and calibrate antennas and ...
Vibrators are relatively unreliable as electromechanical components of limited life, buzz audibly, and produce radio interference. A few radios used a bulkier and more expensive motor-generator or motor-alternator set called a "dynamotor" that spun a high-voltage generator or alternator using a 6- or 12-volt DC motor. Filaments were powered ...
Limiting pressure velocity is a tribological term relating to the maximum temperature and compression that an assembly with rubbing surfaces can bear without failing. Pressure-limiting valves are a type of pressure control valve. They safeguard the system against excessive system pressure or limit the operation pressure.
ADCPs with three beams resolve the three components of velocity. (Models Aquadopp Profiler 1MHz and 0.6 MHz, Nortek) Head of an ADCP with four transducers (Model WH-600, RD Instruments) ADCPs contain piezoelectric transducers to transmit and receive sound signals. The traveling time of sound waves gives an estimate of the distance.
The 8–meter band (40 MHz) is at present the lowest portion of the very high frequency (VHF) radio spectrum available for national amateur radio use. The term refers to the average signal wavelength of 8 meters. The 8–meter band shares many characteristics with the neighboring 6–meter and 10–meter bands.