More information: https://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System

http://aprs.org/ http://www.arrl.org/aprs-mode

http://www.aprs-is.net/

https://aprs.fi/#!lat=33.5&lng=-86.5 https://www.aprsdirect.com/center/33.50000,-86.80000/zoom/8/time/60

APRS Packet Nodes and Locations

Frequency	Location	Callsign	Type
144.39	Birmingham	K4TQR-1	DIGI
144.39	Cheaha	WB4GNA-7	DIGI
144.39	Moody	KD4EXS	IGATE
144.39	Pinson	KM4NDI-10	IGATE
144.39	Warrior	N4XWC	IGATE
144.39	Bear Creek	KG4PID-14	IGATE
144.39	Tuscumbia	W4ZZK-11	IGATE
144.39	Corner	KD4CIF	DIGI
144.39	Vincent	KU4BL-3	IGATE