Timewave DSP-232, Operating Manual

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Chapter 6 GPS Applications
1. Connect your TNC to your computer and get it up and running following the directions in Chapter 2.
2. Type MY <your call sign>-9 , then press ENTER. For example, if your call sign is WA7GCI you would enter
MY WA7GCI-9, then press ENTER. The -9 will cause others to see you as a car on the APRS map.
3. Program the UNPROTO command to: UN APRS via RELAY , then press ENTER. This programs your
unproto path to APRS via RELAY.
4. Type GLOCtx 6, then press ENTER. This causes the TNC to transmit its GPS location every 60 seconds.
The seconds can range from 0 (disabled) to 255 in ten second increments.
5. Now you need to program the commands, GNMEA1 and/or GNMEA2, for the desired NMEA (GPS)
sentences for the DSP-232 to parse. Not all GPS receivers can send all NMEA sentences. So, the instructions
you see below depend on the ability of your GPS receiver to send desired NMEA strings. In any case, the
DSP-232 can handle any NMEA strings your GPS or Loran receiver can produce.
To program GNMEA1, type GNMEA1 $GPGLL and press ENTER. This command allows the DSP-232 to
parse the Position-Only NMEA string coming from the GPS receiver and place the string in the transmit
buffer. The result of $GPGLL is that you will be able receive from the GPS receiver Position-Only
information and transmit it over the ham bands. (Any NMEA string your GPS receiver can produce can be
entered in this command line.)
The neat thing about the DSP-232 is that you can choose not one, but two NMEA strings to parse. You can,
for instance, use Position-Only and Course/Speed. To program the second NMEA string for the DSP-232,
type GNMEA2 $GPVTG and press ENTER. This sentence alone allows you to transmit course and speed.
When coupled with the GNMEA1, your position, course, and speed will be transmitted together. (Again, you
can use any NMEA string your GPS receiver can produce in this command line.)
Note: The NMEA sentence $GPRMC is the recommended sentence for tracking moving objects as it contains
time, latitude, longitude, course, and speed information--all in one sentance.
6. Now type GPSAuto ON then press ENTER. This will cause the DSP-232 to look for GPS data (coming from
an attached GPS receiver) the next time it is powered on, and if it sees GPS data the DSP-232 will
automatically switch to GPSMode 1 .
7. Now you need to program the DSP-232’s terminal baud rate to match that of the GPS receiver, which is
normally 4800 baud. To program the DSP-232 terminal baud rate, type TBAUD 4800 , then press ENTER.
8. Now turn your DSP-232 off and disconnect your TNC from the computer. Take the DSP-232 to your vehicle,
connect the TNC to the GPS receiver and the radio, plug it in, power it up and you’re in business.
Connecting the GPS receiver to the DSP-232
6-4 September, 05