Someone is bound to say “Wait ! Cars ? People ? Weather Stations ? These things are small potatoes. How do they ‘get out’ ?”
Go listen to the short bursts on 144.390 MHz for a few minutes.
Messages (aka “packets”) transmitted from these transmitters (the soft bursts) are stored then repeated (the LOUD bursts) shortly there after by digipeaters (digital + repeater, get it?). The “digis” are also called store-and-forward repeaters, and long story short, each one makes an adjustment in the “header” of the packets (think address and return address of a letter) and passes along a perfect copy of the packet’s “payload” (consider the payload like the body of a letter.)
The local Digi is called ETULSA. Check it out.
RF to Internet
So what gets the packets flying around Tulsa into the Internet ? That is a special type of repeater composed of an Internet connection and a radio (instead of two radios) called an IGate.
The regional IGATE is W5BGM. It hears ETULSA and passes those packets over the Internet to a server in Texas.
See ? http://aprs.fi/?call=a%2FW5BGM
Click around and have fun.
Scott / KD5NJR