KPC3.TXT KPC-3 LTRACK BUFFER COMMANDS Document version: 8.3.5 10 Mar 99 Author(s): Bob, KC5EJK or ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ COMMENTS ON THE LTRAK BUFFER: Bob, kc5ejk@onramp.net or kc5ejk@amsat.org Here's how to set the buffer storage inside the TNC to save the GPS data. Do only once before getting data, as I think this clears the buffer. LTRACK LTRACK 5 LT1 LT2 LT3 LT4 or LTRACK 5 LT2 for only saving the LT2 data which is $GPRMC per my GPSHEAD setting. With the standard 32K of memory 17 is the largest I could set this value. Note the data is stored in the buffer at the rate set by the BLT beacon command not the rate the GPS sends date to the TNC. INTERFACE GPS causes the TNC to power up in GPS mode. INTFACE {TERMINAL | NEWUSER | BBS | KISS | HOST | GPS} ----------------------------------------------------------------------- How to READ GPS track DATA from the TNC buffer: login to the TNC BBS as callsign-1 LTRack n [string] DISPLAY LAST n MSGS IN TRACK BUFFER LTRACK 50 Read 50 lines of data from the buffer LTRACK 50 $GPGGA Read 50 lines of $GPGGA data from the buffer. The data is dumped back in LIFO format (last in first out) which is backward of what you are expecting for a trip log using APRS. --------------------------------------------- The other settings you must do to the kpc-3: Setting for which NEMA sentences you want to record or beacon You get to set up to 4. I use only two GPSHEAD 1 $GPGGA 2 $GPRMC The LT buffer filled with real GPS data LT 1 $GPGGA,064301,3250.743,N,09645.669,W,1,05,2.6,236.7,M,-24.8,M,,*71 2 $GPRMC,064303,A,3250.742,N,09645.668,W,002.4,121.2,040695,,*06 The LT buffer when the GPS is not seeing any satellites. LT 1 $GPGGA,100552,,,,,0,00,,,M,,M,,*65 2 $GPRMC,100551,V,,,,,,,020695,,*39 Setting the beacon time for the GPS data, I use $GPGGA two times a min and $GPRMC once a min. Note the offset so DIGIs have time to respond BLT 1 EVERY 00:00:30 2 EVERY 00:01:10 3 EVERY 00:00:00 4 EVERY 00:00:00 Setting for the output APRS format LTP 1 APRSM VIA RELAY 2 APRSM VIA RELAY,WIDE 3 NONE 4 NONE