APRS logo

New version 2.0 software using

for both normal tracker and TXtracker

APRS logo

The new software uses an AT89S4051 from Atmel. This CPU is an upgraded version of the "old" AT89C4051.
Some of the new Features in AT89S4051 are :
On-chip Analog Comparator with Selectable Interrupt.
Programable x2 Clock Option.
256 Bytes of Internal RAM.

The following features has been added to the Tracker:

  • Timestamp of Packets (Gets time from GPS in the format hh:mm:ss).
  • Warm-up Time for the GPS Adjustable from 1 sec to 255 sec.
  • Option for 300 Baud with 1600 Hz/ 1800 Hz tones for HF use.
  • Option for 300 Baud with NRZI for HF use .
  • Option for Receive Packets (Not available in smartbeaconmode and in the TXTRACKER !!)

For receiving packets adjust R18 to an DC voltage difference of 100 mV between pin 13 and pin 12 (the comparator inputs) of the AT89S4051.
or you can make the hardware modifications show below :

Modifications for version2

Part of the shematic with the modifications
Modifications for version2

On the PCB component side remove the original R18 (50 KOhm variable resistor)
and on the copper side of the PCB add (a new) R18 (39 KOhm) and R33 (560 KOhm)

There are only 1 connector for RS232 on the tracker. In order to connect both a GPS and a PC or LCD unit you must split the signals.
The PC or LCD unit are connected to TXD (Data FROM the tracker) and the GPS unit are connected to RXD (Data TO the tracker).

Connection to GPS and PC Connection to PC

Interface cable between tracker and PC or LCD unit and GPS

The RS232 signals are divided in two on P2 and P3 :
PC or LCD are connected to TXD (Data from the Tracker) on P3
and the GPS are connected to RXD (Data to the Tracker) on P2
and GPS power to the mini DIN connector on the Tracker.

Interface cable between tracker and PC or LCD.

Used if the Tracker are modified for GPS BR355. The GPS
is connected directly to the mini DIN connector ( P2)
on the Tracker or TXtracker.
See the modifications HERE

The above shown interfaces can not be used for programming the tracker

For programming use the interface cable shown below connected directly to the Tracker P1.
Programming cable

PCB with LCD

PCB with AT89C4051 showing the packets on
a 4 lines 20 characters display.


Communication program with a screendumb of received packets
(on an "old" DOS computer).

Setup program

Setup program

There is a small "bug" in the Configuration Program. If you are using WIDEx-x
you must replace "-" with a space i.e. "WIDE1 1" and NOT "WIDE1-1". See picture below

Wide corrections

After connecting power to the tracker the green and red LED will be flashing. The last LED lit shows the configuration used.
Green LED : configuration 1
Red LED     : configuration 2
When the LEDs stops flashing the tracker sends a string out on the RS232 dataline (with 4800 Baud) :
OZ4HZ APRS (RX) Tracker with 80S4051 ver 2.0 07 07 06
If the GPS unit is connected to the tracker it is powered up as well and the tracker will wait for approx. 30 sec for the GPS signals to get valid. If the GPSdata are valid a transmission takes place and the transmitted data are also send out on the RS232 dataline ie.: )
OZ4HZ>APTZ20,TRACE2-2:/102745h5541.90N/01230.41E-176/000 Tracker from OZ4HZ config 2 15 min fixed
If you don't use SmartBeacon mode then ( and a receiver are connected to the tracker ) the received packet will be available on
the RS232 dataline (some examples are shown below) :
OZ1ISU-9>APZ100,OZ5DIB-1*,OZ4DIB-2*,TRACE4-3:!5556.37N/01216.87E>011/000/A=000234/QRV 434.850gilleleje pilot 82hz -2mhz
OZ7QF-9>APZ100,RELAY,TRACE3-3:!5539.19N/01228.05E>000/000/QRV Repeater 51.950 & 145.750, 434.675, 1297.150 MHz
OZ0CAB-7>APU25N,RELAY,TRACE3-3:@091019z5541.18N/01227.03E>161/024_OZ1IEP at his Taxi {UIV32}

The normal function of the LEDs:
Red LED :
On for 50mS once every second
On when TX are keyed
Green LED :
On with activated carrier detect or when receiving packets.
On when TX keyed and data from GPS is OK.

During normal operation you can switch to another configuration with the switch S1. The LEDs will flash and show the new configuration

 Monterings vejledning ver 2
 Setup program decription (pdf)
 Setup program and decription (zip)
 Ver 2 (rev. 2008-12-08) 8051 Assembler files (zip)
 Ver 2 (rev. 2008-12-08) HEX file (zip)
 Ver 2 (rev. 2008-12-08) HEX file for DJ7OO PCB (zip)
 Ver 2 Schematic (pdf)