Aprs Networks; Servers; Igate - Kenwood TM-255A Product Manual

7 APRS NETWORKS

7.1 Servers

In the beginning, APRS networks consisted only of general packet transmissions through digital
repeaters. To expand network coverage much further, HF gateway stations that were interfaced
with the VHF stations were added. This arrangement evolved still further when it became
common for personal computers to be connected with the Internet. Internet gateways provided
another way to expand APRS coverage. APRServe, developed by Mr. Steve Dimse, K4HG,
allows information that is gathered from the Internet to be transferred to client computers. The
worldwide APRS network was completed. The service is called APRS IS (APRS Internet Service).
At present, there are several basic servers that are called Core servers. Approximately 40 local
servers, called Tier 2 servers, are located worldwide in each participating country and work under
the Core servers. Later, Pete Loveall, AE5PL developed javAPRSSrvr to establish a Tier-2
distribution system to better handle regional APRS-IS feeds. The Internet part of the APRS
system is called APRS-IS (APRS-Internet Service).

7.2 IGate

There are basically two ways to use APRS-IS effectively when operating APRS: a client personal
computer connected directly to Core/ Tier 2 servers, and using amateur radio with IGate (Internet
gateway).
For client use, a callsign is required, but amateur radio equipment is not necessary. You simply
install APRS software on a personal computer, configure the necessary station information and
connect to an APRS server via the Internet. With this arrangement, you can enjoy the basic
features of APRS such as transmitting your own station position, exchanging messages and
dispatch or receipt of weather information.
Using TM-D710A/E or RC-D710, you can transmit your own packet signals via amateur radio and
use APRS-IS to access IGate. IGate acts as a two-way interface between the Internet and
amateur radio packet signals. The IGate function is obtained through various releases of APRS
software and IGate is commonly available as a result of many volunteer amateur radio operators.
IGate connects directly to Core servers and Tier 2 servers. Information received by amateur radio
packet transmissions is transferred to the servers, and server information can be passed via
packet radio transmissions back to amateur radio operators.
New IGate stations in areas where IGate access is already available are added as necessary as
traffic warrants. Traffic from IGate to amateur radio stations increases air traffic which can
undesirably overload frequencies. Therefore, you must be familiar with operational configurations.
Various filtering functions exist so you should be knowledgeable about your local existing IGate
station. It is best to minimize traffic as much as possible. In the case of packet messaging,
bidirectional data transfers are used.
To use TM-D710A/E or RC-D710 efficiently at a fixed station includes configuring the callsign and
the packet path to your local IGate station. In cases of mobile stations, you can similarly initially
configure the packet path, but it is good to follow local rules of each new area where you may
operate.
TM-D710A/E 31
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