Digipeater
A digipeater (from English digital repeater ) is an automatically operating transmitting and receiving station for forwarding digitally coded information between two radio stations . Analogous to the digipeater in radio data transmission, speech radio is referred to as a relay station and data transmission via cables is referred to as a repeater .
Digipeaters are mainly used for packet radio in amateur radio and now also in CB radio .
Digipeater in the amateur radio service
In the amateur radio service there are currently more than 512 digipeaters in Germany and around 1800 in Europe. In Germany the digipeaters are interconnected with more than a thousand connections. Users can contact the digipeater on selected frequencies and then connect across the network.
The speed of data connections from the user to the digipeater is usually 9600 baud (Bd) today . Often there are still accesses with 1200 Bd., But also those with 38.4 kBd in operation. In the case of link connections, symbol rates of 300 Bd. In shortwave bands up to 1.2 MBd in VHF and gigahertz bands can be found. A digipeater can have several entrances and connections to other digipeaters.
In the past, computers with a modem connected to each serial interface often worked as digipeaters. Several modems were later combined at one interface using a token ring . Special interface cards have also been developed. There are now Terminal Node Controllers (TNC) with such large computing capacities that there is no need for an additional computer.
Often other computers are connected to digipeaters to provide additional services. So a large mailbox network has been organized in which one can distribute personal and public messages. The DX clusters and the POCSAG transmitters for radio signal receivers are also connected to one another via digipeaters.
Digipeater in amateur radio satellites
Digipeaters are also available in various amateur radio satellites as well as on board the International Space Station as part of the ARISS project .
Routing
A distinction is made between logged packet radio connections with a specific remote station and unlogged transmissions to all. In the case of unlogged connections, the originating station specifies how many digipeaters the message is to be transmitted over. Each digipeater reduces this value by 1 when it is forwarded.
See also
literature
- Steve Ford: VHF digital handbook. ARRL, Newington CT 2008.