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The 70-centimeter or 440 MHz band is a portion of the UHF radio spectrum internationally allocated to amateur radio and amateur satellite use. The ITU amateur radio allocation is from 430 to 440 MHz; however, some countries, such as the United States, allocate hams 420 to 450 MHz.
An example of an inverting transponder would be a 70cm to 2m transponder which receives on the 432.000 MHz to 432.100 MHz frequencies and transmits on the 146.000 MHz to 146.100 MHz frequencies by inverting the frequency range within the band. In this example, a signal received at 432.001 MHz would be transmitted on 146.099 MHz.
A440 (also known as Stuttgart pitch [1]) is the musical pitch corresponding to an audio frequency of 440 Hz, which serves as a tuning standard for the musical note of A above middle C, or A 4 in scientific pitch notation. It is standardized by the International Organization for Standardization as ISO 16.
The list of frequency ranges is called a band allocation, which may be set by international agreements, and national regulations. The modes and types of allocations within each frequency band is called a bandplan; it may be determined by regulation, but most typically is set by agreements between amateur radio operators.
Other frequencies are designated for low power simplex operation only. In certain urban areas, additional UHF allocations in the 422-430 MHz band (areas: Buffalo, New York, Detroit, Michigan and Cleveland, Ohio) and/or the 470-512 MHz UHF-T band are also available.
Same band repeaters operate with input and output frequencies in the same frequency band. For example, in US two-way radio, 30–50 MHz is one band and 150–174 MHz is another. A repeater with an input of 33.980 MHz and an output of 46.140 MHz is a same band repeater.
This is a list of the fundamental frequencies in hertz (cycles per second) of the keys of a modern 88-key standard or 108-key extended piano in twelve-tone equal temperament, with the 49th key, the fifth A (called A 4), tuned to 440 Hz (referred to as A440). [1] [2] Every octave is made of twelve steps called semitones.
All signals in the specification use combination (by addition) of audible tones of four frequencies: 350 Hz, 440 Hz, 480 Hz, and 620 Hz. Equipment is required to maintain tolerances within ± 0.5% in frequency and ±1.5 dB in amplitude stability. Harmonic distortion is to be at least 30 dB below the applied tone level. [1] The tones are as ...