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Grundig Satellit 400 solid-state, digital shortwave receiver, c. 1986 [1]. Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength).
ARQ-M, short for Automatic Repeat reQuest, Multiplex, is a radio telegraphy protocol used to reliably forward telex messages over partially reliable radio links. [1] It is a low-speed system designed to match the performance of landline telex systems and allow those messages to be forwarded over long distances using shortwave radios.
Many raters misunderstand the code and will rate everything either 55555 or 11111 when in reality both extremes are unusual in the extreme. 55555 essentially means perfect reception akin to a local station while that is occasionally possible, when talking about long-distance short-wave reception, it is rarely the case.
ARQ-E is a radio transmission method used to send data over short wave radio. ARQ-E is a full duplex synchronous data communications system that requests repeats if data is not received correctly. It uses an alphabet that can detect errors.
Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency [MF] band and all of the high frequency [HF] band). Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a ...
Each channel symbol conveys one sync bit (LSB) and one data bit (MSB). Duration of transmission is 162 × 8192 ⁄ 12000 = 110.6 s. Transmissions nominally start one second into an even UTC minute: e.g., at hh:00:01, hh:02:01, etc. Minimum S/N for reception is around –34 dB on the WSJT scale (2500 Hz reference bandwidth).
The S stands for "Strength". Strength is an assessment of how powerful the received signal is at the receiving location. Although an accurate signal strength meter can determine a quantitative value for signal strength, in practice this portion of the RST code is a qualitative assessment, often made based on the S meter of the radio receiver at the location of signal reception.
A shortwave radio receiver is a radio receiver that can receive one or more shortwave bands, between 1.6 and 30 MHz. A shortwave radio receiver often receives other broadcast bands, such as FM radio, Longwave and Mediumwave. Shortwave radio receivers are often used by dedicated hobbyists called shortwave listeners.