Search results
Results From The WOW.Com Content Network
The bands used by ATV repeaters vary by country, but in the US a typical configuration is as a cross-band system with an input on the 33 or 23 cm band and output on 421.25 MHz or, sometimes, 426.25 MHz (within the 70 cm band).
Crossband (cross-band, cross band) operation is a method of telecommunication in which a radio station receives signals on one frequency and simultaneously transmits on another for the purpose of full duplex communication or signal relay.
Morse code is called the original digital mode. Radio telegraphy, designed for machine-to-machine communication is the direct on / off keying of a continuous wave carrier by Morse code symbols, often called amplitude-shift keying or ASK, may be considered to be an amplitude modulated mode of communications, and is rightfully considered the first digital data mode.
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. In same band repeaters, a central design problem is keeping the repeater's own transmitter from interfering with the receiver.
Linking multiple repeaters to enable a repeater outside the communications range of the handheld or mobile device to retransmit messages violates sections 95.1733(a)(8) and 95.1749 of the Commission's rules, and potentially other rules in 47 C.F.R. Repeaters may be connected to the telephone network or other networks only for purposes of remote ...
The nominal "17 m" band actually covers 16.6–16.5 m. The nominal "15 m" band actually ranges from 14.28–13.98 m. By common sense, the "15 m" band ought to be called "14 m", but that name has been in longtime use for a shortwave broadcast band. 80 metres or 80 / 75 meters – 3 500–4 000 kHz – 85.65–74.95 m actual
Some repeaters have automatic call sign transmission at regular intervals and use the secondary suffix /R at the call sign's end. Some jurisdictions discourage this practice on the grounds that it could be confused with an amateur from the repeater's location working portable in Russia.
Some of these repeaters feature CTCSS/PL tone protection, remote control via DTMF, linking via Internet gateways, simulcasting via several repeaters at once, and cross-band repeat connections to the UHF PMR446 service.