What is CBAPRS?
CBAPRS stands for Citizen Band Automatic Packet Reporting System which consists of a server listening for APRS packets relayed over the internet by radio operators and a webinterface displaying the received information on a Worldmap.
I am using the DUTCH-CB ARPS services hosted by Niels (NL1ZLD) located in The Netherlands. Have a look at his website for more information about packet-radio.
Another APRS map?
Relaying packets to other APRS maps is restricted to ameteur radio operators. As more and more people are starting to use APRS on non amateur radio bands, i.e. citizen band, the need for an open APRS map had to be met. On this page you can find information about three "open" CB APRS services that can be used if you are not a radio amateur.
How to relay packets ?
To send and receive APRS packets on the CB packet radio network please configure your APRS software with one of the following APRS servers:
Host: cbaprs.de Port: 27235
Host: dnr875.de Port: 26875
Host: packet-radio.nl Port: 10152
Keep in mind that you might need to set a valid passcode for your software to transmit packets to an internet server.
APRS (Automatic Packet Reporting System), is a digital communications protocol for exchanging information among a large number of stations covering a large (local) area, often referred to as "IP-ers". As a multi-user data network, it is quite different from conventional packet radio. Rather than using connected data streams where stations connect to each other and packets are acknowledged and retransmitted if lost, APRS operates entirely in an unconnected broadcast fashion, using unnumbered AX.25 frames.
APRS packets are transmitted for all other stations to hear and use. 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. All stations within radio range of each digipeater receive the packet. At each digipeater, the packet path is changed. The packet will only be repeated through a certain number of digipeaters — or hops — depending upon the all-important "PATH" setting.
Digipeaters keep track of the packets they forward for a period of time, thus preventing duplicate packets from being retransmitted. This keeps packets from circulating in endless loops inside the ad-hoc network. Eventually, most packets are heard by an APRS Internet Gateway, called an IGate, and the packets are routed on to the Internet APRS backbone (where duplicate packets heard by other IGates are discarded) for display or analysis by other users connected to an APRS-IS server, or on a Web site designed for the purpose.
While it would seem that using unconnected and unnumbered packets without acknowledgment and retransmission on a shared and sometimes congested channel would result in poor reliability due to a packet being lost, this is not the case, because the packets are transmitted (broadcast) to everyone and multiplied many times over by each digipeater. This means that all digipeaters and stations in range get a copy, and then proceed to broadcast it to all other digipeaters and stations within their range. The end result is that packets are multiplied more than they are lost. Therefore, packets can sometimes be heard some distance from the originating station. Packets can be digitally repeated tens of kilometers or even hundreds of kilometers, depending on the height and range of the digipeaters in the area.
When a packet is transmitted, it is duplicated many times as it radiates out, taking all available paths simultaneously, until the number of "hops" allowed by the path setting is consumed.