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Repeater frequency sets are known as "repeater pairs", and in the ham radio community most follow ad hoc standards for the difference between the two frequencies, commonly called the offset. In the USA two-meter band, the standard offset is 600 kHz (0.6 MHz), but sometimes unusual offsets, referred to as oddball splits, are used. The actual ...
The type of radio emission is “F1D”, frequency-shift keying. A message contains a station's callsign, Maidenhead grid locator, and transmitter power in dBm. [3] The WSPR protocol compresses the information in the message into 50 bits (binary digits).
M17 uses Frequency-Division Multiple Access (FDMA) technology in which different communication streams are separated by frequency and run concurrently. It utilizes 4,800 symbols per second, 4-level frequency-shift keying (4FSK) with a root Nyquist filter applied to the bitstream. Radio channels are 9 kHz wide, with channel spacing of 12.5 kHz.
Repeater systems use two different radio frequencies; the mobiles transmit on one frequency, and the repeater station receives those transmission and transmits on a second frequency. Since the repeater must transmit at the same time as the signal is being received, and may even use the same antenna for both transmitting and receiving, frequency ...
Automatic Packet Reporting System (APRS) is an amateur radio-based system for real time digital communications of information of immediate value in the local area. [1] Data can include object Global Positioning System (GPS) coordinates , non-directional beacon , weather station telemetry, text messages, announcements, queries, and other telemetry .
The current master gateway in the United States is operated by the K5TIT group in Texas, who were the first to install a D-STAR repeater system in the U.S. [10] D-STAR transfers both voice and data via digital encoding over the 2 m (VHF), 70 cm (UHF), and 23 cm (1.3 GHz) amateur radio bands.
Function codes may specify a unit number code (1–16) or a command code. The unit number or command code occupies the first 4 of the 5 bits. The final bit is a 0 for a unit code and a 1 for a command code. Multiple unit codes may be transmitted in sequence before a command code is finally sent. The command will be applied to all unit codes sent.
Monitor mode, or RFMON (Radio Frequency MONitor) mode, allows a computer with a wireless network interface controller (WNIC) to monitor all traffic received on a wireless channel. Unlike promiscuous mode , which is also used for packet sniffing , monitor mode allows packets to be captured without having to associate with an access point or ad ...