Borrowed from NWAPRS

Basic Settings for Home Ops Mobile KPC-3/+ v8.2 Notes for KPC-3+ 8.3

Wide digipeater site KPC-3/KPC-3+ v8.2+

Mobile TM-D700/TH-D7A

WX Stations
Portable (MIM, PIC, TigerTrack, TinyTrack)  

Basic TNC Settings for Home Operations

When you purchase a new TNC and turn it on for the first time, it contains several default settings that you must first re-program before operating it with APRS.

If the new TNC is a Kantronics KPC-3 Plus or KAM, in addition to the MYCALL and MYPBBS and other settings, you also must adjust INTerface from NEWUSER to TERMINAL. This opens additional fields for re-programming. Adjust HEAderline to OFF, and MCOM and MCON to OFF. For home ops you can use any BAUD rate setting, but I like to use 4800 because it keeps me consistent with all my TNCs since the Tracker TNCs require ABAUD 4800 for interface with the GPS. Whatever ABAUD setting you choose, remember it, as when you start APRS for the first time it will ask you, among other questions, what your baud rate is set at.

There are several improvements with the introduction of Kantronics firmware releases 8.3 and 9.0. Most importantly, the GPS data output can be inserted via DE-9 pins 2 and 6 on the TNC. Also, you do not need to change INT to GPS. Leave INT TERMINAL when using an 8.3 TNC. More info is available separately. This applies to using a newer KPC-3+ for use as a mobile tracker.

After starting APRS, and you believe you are communicating OK with the TNC, you can now watch for stations to appear, and your packets to begin sending over the system.


IMPORTANT: Set your path to minimum to reach an Igate: Wide2-1 preferred


Note that you DO NOT have to purchase one of the brand-spanking new APRS/GPS capable TNC's in order to participate in APRS activities. Many older TNC's can be used, including the AEA PK-88, TAPR-2, TAPR-2 clones made by various manufacturers, etc. These units can be put to use as home stations or as mobile APRS stations. For a home station the position is set in the beacon text and is broadcast at 10 minute intervals. For mobile APRS these TNC's must have a computer attached and running APRS software in order to update the position. The older TNC's are not usable as WIDE digipeaters, and are ill-suited as mobile/portable trackers unless some form of computer is attached constantly.

TAPR-2 clones can be upgraded with new EPROM's to make them GPS-aware. There are certain caveats with this, because the processor inside the TAPR-2 TNC's is slow and may not handle continuous sentences from a GPS. If your GPS has enable/disable for individual sentences then you may want to turn off all strings, and then re-enable just the $GPRMC or the $GPGGA string so the TNC can keep up with the data. See the TAPR Site for information about updated EPROMS. These updated EPROM's are only necessary if you wished to run a mobile APRS setup with no computer attached.

When using an older TNC for your house and WIDE1-1(old relay) station, insert your position fix in the BTEXT, set the TNC to beacon at 30 minute intervals, and set up an alias of "WIDE1-1". Here is an example:

	mycall ab7c

	myalias WIDE1-1

	unproto aprs via WIDE2-1

	btext !1234.56N/76543.21W-

	beacon every 30 (might need to be 600 depending on TNC)

	txdelay 30

	digipeat on

	xmitok on

TNC's are now available that have two serial ports and a radio port. One serial port can connect to a computer, while the other connects to a GPS. If you already own TNC's that only have one serial port, don't despair, there is a way to hook up a GPS and the TNC to the computer at the same time: It's called an HSP (hardware serial port) adapter. You can either build or buy an HSP adapter, and it generally consists of a Y-adapter cable with a small circuit inside. The circuit switches between the TNC and the GPS based on a handshake line coming out of the computer. This handshake line is in turn controlled by the APRS software running on the computer. You merely have to inform the APRS program that you're using an HSP adapter. See the main NWAPRS web page for a pointer to the circuit, or visit the TNC manufacturer's web pages to see what they offer.

Kantronics KPC-3 and KPC-3 Plus

(For KPC-3, connect GPS data to Pin 2, GPS Ground to Pin 7 of TNC DB-25 terminal connector)
(For KPC-3 Plus, connect GPS data to Pin 2, GPS Ground to Pin 6 of TNC DE-9 radio connector)

TNC SETTING KPC-3, KPC-3 Plus TRACKER (up to 8.2, not 8.3)




E 30


1 E 00:01:00
2 E 00:02:00 START 00:01:00 CLEAR
3 E 00:03:00 START 00:02:00 CLEAR


>(Text), begin with a > so it shows up in the status line of APRS software






1 $GPGGA (don't use a combo of $GPGGA and $GPRMC.)
3 $GPGGA   (USE $GPGGA or $GPRMC only)






1 GPSLV (refer to mysymbol.txt for your Icon)
3 GPSLV V WIDE1-1,WIDE2-1 (or wide2-2 in rural areas)


NONE (Do not use WIDE1-1 here)




(CALLSIGN SUFFIX)R-9 (EG GPSR-9).... up to you


(Secret text known only to the control operator)




If you have a KPC-3 Plus with 8.3 or 9.0 firmware, input the GPS data to the KPC-3 Plus DE-9 pins 2 and 6 (data and ground, respectively). This frees up the DB-25 port, so if you want to run it as a tracker, you can, and if you want to run APRS mobile with a laptop, just plug in the computer cable and go. No other changes are necessary. Additionally, make these settings in the KPC-3 Plus (8.3 or 9.0 only):


*Check the SYMBOLS.TXT file for recommended settings for special event trackers. You can use tactical callsigns such as SAR01, Bike1, EOC1, etc, and then place the station callsign in the BTEXT with a 10 minute beacon. To get the desired symbol, place it in the TO CALL of the UNPROTO line, e.g. U GPSxyz via WIDE1-1,WIDE2-1 where "xyz" is derived from SYMBOLS.TXT. Most common symbols:

GPSHT = Running Man
GPSLJ = Jeep
GPSPU = Pickup Truck


If you have a weather station (Davis, Peet Brothers, Radio Shack, etc) at your home or remoted station, we want to see the weather data every 15 minutes. Not more, not less. Additionally, those with weather stations may use WIDE2-1 for their outgoing path from home, or if remoted as a WIDE digipeater on a mountaintop. The extra "hop" helps ensure that the wx data gets to the nearest iGate, which insures delivery to regional NWS stations.

Hooking up a home weather station and integrating it with APRS means you must have two available serial ports on your computer; one for the TNC, and the other for the WX station. If running APRS on a laptop with one serial port, input the weather on the serial port and the TNC via a serial-to-USB connector.


If you operate either the Kenwood TH-D7A or TM-D700, you know how easy it is to reach over and change the periodicity of your transmissions, and the outgoing path. As a default resource, your settings should be WIDE1-1,WIDE2-1 at once every three minutes. However, if you want to transmit every minute, that's OK, just adjust the path down to WIDE1-1. These are very versatile radios, and easy to program "on the fly".

Robert/KD7DPU, added the following: It appears (at least in the NW) that the default setting of 500ms TX delay on the TH-D7A is way overkill. I have successfully tracked with 100ms and 200ms. Up to 400ms of time savings may not seem like much, but it does add up. Moving from 500ms to 100ms (the minimum I believe) is certainly noticeable when monitoring on frequency.


There are several other options, all aimed at size-reduction, for making a tracker. These items inlcude the PIC, MIM, TinyTrack II & III, Mic-E, and Tigertronics TigerTrak TM-1 devices. The smallest of these is about the size of a 9-volt battery, while the largest is still smaller than a pack of Lucky Strikes (non-filtered, of course). All these devices are designed to either fit inside another key component, like a GPS or radio case, and work towards making a smaller, lighter, tracker. These work great for backpack, balloon, vehicle, or rocket trackers, and several of them work off of 5-12 volts. In any case, you typically program these devices externally with a PC, then set them on their way. With exception of the Mic-E and TigerTrak, once programmed, they cannot be changed enroute. Your default settings are determined by the type of operation you are using them in, and will vary accordingly. Typically, it won't be necessary to set any of these trackers above WIDE1-1,WIDE2-1, so you can follow the rules for timing (no relay or WIDE1-1 = 1min, WIDE1-1,WIDE2-1 = 2 mins, WIDE1-1,WIDE2-1 = 3 mins). Use your best judgment when setting the timing options for these kinds of trackers.