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Sailmail
SailMail is radio based e-mail system designed for boat owners operating beyond line-of-sight radio links to the internet. Much of its underlying technology is built upon the Winlink software originally developed by amateur radio enthusiasts. Operation on SailMail network frequencies requires a PACTOR modem and an SSB radio. Sailmail operators do not need to hold an amateur radio Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emer ... license, as is the case for the similar Airmail product. As of December 2023 the annual membership cost was US $275. References External links Official SailMail Site Yachting {{Wireless-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winlink
Winlink, or formally, Winlink Global Radio Email (registered US Service Mark), also known as the Winlink 2000 Network, is a worldwide radio messaging system that uses amateur-band radio frequencies and government frequencies to provide radio interconnection services that include email with attachments, position reporting, weather bulletins, emergency and relief communications, and message relay. The system is built and administered by volunteers and is financially supported by the Amateur Radio Safety Foundation. Network Winlink networking started by providing interconnection services for amateur radio (also known as ''ham radio''). It is well known for its central role in emergency and contingency communications worldwide. The system used to employ multiple central message servers around the world for redundancy, but in 2017–2018 upgraded to Amazon Web Services that provides a geographically-redundant cluster of virtual servers with dynamic load balancers and global cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PACTOR
PACTOR is a radio modulation mode used by amateur radio operators, marine radio stations, military or government users such as the United States Department of Homeland Security, and radio stations in isolated areas to send and receive digital information via radio. PACTOR is an evolution of both AMTOR and packet radio; its name is a portmanteau of these two technologies' names. PACTOR uses a combination of simple FSK modulation, and the ARQ protocol for robust error detection and data throughput. Generational improvements to PACTOR include PACTOR II, PACTOR III, and PACTOR IV which are capable of higher speed transmission. PACTOR is most commonly used on frequencies between 1 MHz and 30 MHz. History PACTOR ''(Latin: The mediator)'' was developed by Special Communications Systems GmbH (SCS) and released to the public in 1991. PACTOR was developed in order to improve the reception of digital data when the received signal was weak or noisy. It combin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency, emergency communications. The term ''"radio amateur"'' is used to specify ''"a duly authorized person interested in radioelectric practice with a purely personal aim and without wikt:pecuniary, pecuniary interest"'' (either direct monetary or other similar reward); and to differentiate it from commercial broadcasting, public safety (police and fire), or two-way radio professional services (maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and ''amateur-satellite service'') is established by the International Telecommunication Union (ITU) through their recommended radio regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-sideband Modulation
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of signal modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
