Setting Up an APRS/Internet Gateway

Steve Dimse K4HG

I am often asked how to set up an internet gateway (IGate) for APRS data. Doing so requires dedicating a computer/radio/tnc to the task, along with some method of connecting to the internet, either a full time network connection or dedicated phone line.

Software Selection

There are two methods of placing APRS data onto the internet. The first of these involves saving blocks of data to a file at regular intervals, usually between 5 and 15 minutes. Such "almost live" sites often provide a number of files that go back different lengths of time, or report different types of data. The best examples of this method is Bob Bruninga's site in Annapolis. These programs are written by their operators, as far as I know there is no 'package' of this software, if you'd like to do it this way, contact the authors for details.

The second way is to gate data onto the internet is as a continuous live stream. This method has the advantage of allowing continous update of the display. At present, the software has been written for the following platforms:

OS Name Author
Macintosh APRServe Steve Dimse K4HG
OS/2 and Linux APRS Server Dale Heatherington WA4DSY
Windows NT LIDS Steve Boyle KD6WXD
Windows 95 QQServ Brad McConahay N8QQ
Linux aprsmon Alan Crosswell N2YGK

These programs are each in use at a handful sites. The installation of such a site is still very much a one-off operation, so contact the author of software appropriate for your OS for help.

Internet Connection

To provide a useful service, an APRS IGate should be available all the time...this provides the hurdle that keeps most people from setting up IGates. The best solution is a direct, high speed internet connection. I was lucky enough to get access at the Miami Museum of Science, others have done this at schools or work. One site (WA4DSY)uses high speed RF modems over ham frequencies to accomplish the connection. A handful of others use dial up connections to do it. While most people have access to dial up connections, there are a couple of pitfalls that need to be avoided.

Most ISPs are not too happy about a user that stays connected all the time. They may try to force you to a dedicated commecial line at $100 or more a month, or try to limit the length of each session. I have no good advice here, I get nasty letters from both my ISPs all the time, and I only connect when I am at the computer.

Once you have found a sympathetic ISP, you need to address the dynamic IP problem. When you log on the internet with most dial-up ISPs, you are assigned an IP number (a 32 bit number, usually expressed like for their available pool--this number will be different each time you log on. In order to access your computer, a user need to know this 32 bit number. Since humans don't remember numbers too well, the internet includes a way to translate a name like into the IP number. However, this system was only designed to translate fixed IP cannot handle dynamic IP. The best solution to this I've found is a company called They provide a server that listens for short packets sent by a program running on your computer, and from that figures out your current IP number and handles the conversion. I wrote the Macintosh client (freeware) for this system (Disclaimer: I get free service, otherwise I have no stake in the company). They charge $19.95 per year for this. Users access your computer by entering the name you choose followed by am "".

A less elegant, but free, solution is available from Monolith Internet Services. They rely on you to update your record every time you change IP numbers, and have no time out...if you get disconnected, people connecting to your name will get routed to someone else's computer!

Another Way...

My APRServe program not only takes the local data from Miami and places it on the internet, it also connects to all the other live servers and consolidates the data into a single stream. In this way a user may get all the internet activity on line from a single site. APRServe has another feature that is useful. Any data it hears on a connected port is echoed to all other connected ports. In this way, it will be possible for part time users running Mac/WinAPRS to fill in the gaps between full time stations. MacAPRS and WinAPRS already has the ability to access APRServe directly and there is a special version of APRSdos called APRSnet that can work through Telnet connections. This also provides a good opportunity for special events...I have a simple Mac program that echos TNC data to APRServe from a local TNC via a dial-up connection, and QQServ can be used in this fashion as well

The Bottom Line

This is still not a plug-and-play thing. If you have the internet access and the hardware, contact me or one of the other gate software authors to help you get going. I have written a little more information for Macintosh users.