GPS Receiver User Manual

2 HOW YOU ENJOY APRS WITH TH-D72A/E (WRITTEN BY BOB BRUNINGA, WB4APR)
6 CONTENTS TH-D72A/E
APRS-IS
In 1997, K4HG and the Mac/WinAPRS Sproul brothers tied APRS to the Internet and the APRS-IS
system as shown above was born. While this was a huge success that enabled instantaneous global
APRS texting connectivity beyond our wildest dreams, it also further enhanced the map view
experience of casual APRS viewers. Looking at an APRS map was colorful but it did not obviously
convey the human contact and connectivity inherent in the system. Also, it was impossible to
communicate with all of the one-way trackers equipment and the value of two-way amateur radio
communications was further being lost in favor of simple two-dimensional icons on maps. Further
these simple icons omitted the other 8 dimensions of color attributes that gave additional at-a-glance
real time information to viewers.
See http://aprs.org/symbols.html
APRS Handheld and Mobile Radios
To counteract this trend, we stopped using “Position” and went back to the original “Packet”
nomenclature for APRS. Then in 1998, Kenwood gave a landmark boost to APRS in the field and to
this digital communications capability by introducing the fully integrated TH-D7A/E. Thus TH-D7A/E
put APRS in the palm of the hand of ham radio operators worldwide. Not only did it take GPS inputs,
but it fully implemented the APRS messaging, bulletins and texting capabilities. Over the next 11
years, this predecessor to the TH-D72A/E was the most popular Kenwood HT ever as APRS brought
new life to packet radio. In parallel, Kenwood also introduced the fully integrated TM-D700A/E
mobile APRS radio in 2000. These APRS front-panel-display radios now brought the full APRS local
situational awareness to the mobile operator as shown below. With these displays, the APRS
information content delivery system was in place without any need for mobile PC’s or laptops.
Further, the attached GPS provided the map display and the radio display provided all the other
information content.