APRS TNC Settings -- What You Should Use In 2009 and Beyond
APRS is a very popular digital mode. You can send and receive short messages, track vehicles, announce meetings, identify critical locations, etc. The problem with APRS is that there is far more outdated information on how to setup your TNC than there is good information. Do a search and you'll find hundreds of web sights on how to configure APRS. The vast number of them a) have no date so there's no clue as to whether they are current, and b) give you information that if followed today will actually hurt APRS network performance. Hint: If the web site tells you to use settings that include WIDE or RELAY in the path it is seriously out of date. Do not follow the instructions there.
Bob Bruninga WB4APR invented APRS and remains extremely active in it's use and development. With him still involved I believe it's a safe bet that he would have the most current information available on what to do and what to not do in terms of settings.
The link below is a PDF file created from Bruninga's July 24, 2009 paper describing the recommended settings for the Kantronics KPC-3+ TNC. I created the PDF version solely to end up with an uneditable version that had the date as a part of the name. If you are not using a Kantronics TNC many of the settings will still need the same values given. The commands to change them may be slightly different.
24-JUL-09 KPC-3 WIDEn-N Settings
The original plain text files with this information are available online as well as a lot of other good information. The site includes a lot of historical information which is interesting but can lead you astray if you think you are implementing the current practice when in fact you are looking at old materials.
Click Here for the APRS.org Web Site
TACTICAL CALL SIGNS
There are occasions when it is advantageous to use a "tactical call sign" as opposed to your FCC issued call sign. For example, when supporting a bicycle race if the Support and Gear Vehicles would show up on a live APRS map as SAG1, SAG2, etc. that provides useful information. No one may remember whether N9PUZ-7 is a SAG vehicle or is carrying a medic.
If you use a tactical call sign in the MYALIAS field of your TNC you must still include and broadcast your FCC call sign once every 10 minutes to remain legal. The easiest way to do this is to include your FCC call sign in the beacon text and setup the TNC so it is transmitted once every ten minutes.
Updated April 9, 2012