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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 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz [1] in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) [2] [3] and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia).
The standard message is <callsign> + <4 character locator> + <dBm transmit power>; for example “K1ABC FN20 37” is a signal from station K1ABC in Maidenhead grid cell “FN20”, sending 37 dBm, or about 5.0 W (legal limit for 630 m). Messages with a compound callsign and/or 6 digit locator use a two-transmission sequence.
Usually used as an ATV repeater output. VSB filters must be used on this channel to keep the signal inside the ham band. Channels 58 and 59 are often offset in frequency to limit interference to the weak-signal and amateur radio satellite sub-bands (431–433 & 435–438 MHz respectively). Many modern CATV receivers can still lock-on to ...
In order to reduce the interference from the fringe area transmitters transmitting in the same channels, a method named frequency offset is often used. By this method, a slightly shifted RF is assigned for a transmitter which may experience interference from other transmitters. In TV transmission, the shifted RF is calculated by the formula;
(2) Shared FRS and GMRS simplex; GMRS repeater output. (3) GMRS repeater input. The output frequency of this repeater input is the input frequency minus 5 MHz. (4) FRS transmissions are limited to bandwidth of 11 kHz with a transmitter deviation of +/- 2.5 kHz. Channels are on 12.5 kHz centers.
Packet repeaters, called digipeaters, form the backbone of the APRS system, and use store and forward technology to retransmit packets. All stations operate on the same radio channel, and packets move through the network from digipeater to digipeater, propagating outward from their point of origin.
These satellites can be used free of charge by licensed amateur radio operators for voice (FM, SSB) and data (AX.25, packet radio, APRS) communications. Currently, over 18 fully operational amateur radio satellites are in orbit. [2] They may be designed to act as repeaters, as linear transponders, and as store and forward digital relays.