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[aprssig] Help with Interfacing a GPS to Kantronics KPC-3

EXT-Maetta, John john.maetta at boeing.com
Wed Jan 3 22:01:19 UTC 2007


Hi Earl,

It has been a long time since I have operated this KPC and packet, so I
am relearning too.

I will try the Beacon. Here's the original message text:

Greetings to all. 
 
This is my first post to the SIG.
 
I am experiencing problems interfacing my Magellan GPS Tracker to the
Kantronics KPC-3. KPC-3 settings are as follows:
 
GPSHEAD
1 $GPGGA
2 $GPRMC

LTP
1 GPS VIA DIGI
2 GPS VIA DIGI
3 GPS
4 GPS
 
BLT
1 EVERY 00:00:10
2 EVERY 00:00:20
3 EVERY 00:00:00
4 EVERY 00:00:00
 
LTRACK   1 LT1 LT2
 
ABAUD    4800
 
I set INTERFACE to GPS, power off KPC-3, connect GPS to DB-25 connector,
power up GPS and then power up KPC-3.  Using the above configuration,
the KPC-3 should Xmit the $GPGGA GPS string every 10 seconds and the
$GPRMC GPS string every 20 seconds.  
 
The Xmit LED does not illuminate so I assume that the KPC-3 is not
recieving the strings correctly or transmiting.
 
I can connect my GPS to my laptop serial port and receive NEMA183 data.
I can view the $GPGGA and $GPRMC strings, along with several other
$GPxxx strings. 
These strings are updated every second, therefore I know my GPS is
transmitting data.
 
The following is captured GPS data from my Magellan Tracker:
$GPGLL,3449.9685,N,12026.9276,W,202153.531,A*23
$GPGGA,202153.53,3449.9685,N,12026.9276,W,1,04,2.0,00032,M,,,,*30
$GPGSA,A,3,01,02,03,04,,,,,,,,,2.0,2.0,2.0*34
$GPGSV,3,1,11,12,87,265,,24,87,254,,05,81,265,,02,61,042,*72
$GPGSV,3,2,11,30,48,312,,10,36,137,,06,24,290,,04,19,046,*73
$GPGSV,3,3,11,09,18,203,,07,12,286,,31,02,327,,,,,*46
$GPGLL,3449.9886,N,12026.9276,W,202156.875,A*26
$GPGGA,202156.88,3449.9886,N,12026.9276,W,1,04,2.0,00032,M,,,,*3E
$GPRMB,A,0.00,R,SIM001,SIM002,3452.5112,N,12026.9276,W,002.5,000.,021.7,
V*00
$GPRMC,202156.88,A,3449.9886,N,12026.9276,W,21.7,000.0,030107,15.,E*75
$GPAPB,A,A,0.0,R,N,,,345.3,M,SIM002,345.3,M,345.3,M*71
$GPGSA,A,3,01,02,03,04,,,,,,,,,2.0,2.0,2.0*34
$GPGSV,3,1,11,12,87,265,,24,87,254,,05,81,265,,02,61,042,*72
$GPGSV,3,2,11,30,48,312,,10,36,137,,06,24,290,,04,19,046,*73
$GPGSV,3,3,11,09,18,203,,07,12,286,,31,02,327,,,,,*46
$GPGLL,3449.9886,N,12026.9276,W,202156.875,A*26
$GPGGA,202156.88,3449.9886,N,12026.9276,W,1,04,2.0,00032,M,,,,*3E
$GPRMB,A,0.00,R,SIM001,SIM002,3452.5112,N,12026.9276,W,002.5,000.,021.7,
V*00
 
I then tried send this text file from the laptop to the KPC-3 while in
GPS mode. Still, no Xmit LED or data from the KPC-3.  The KPC-3 should
be parsing the $GPGGA and $GPRMC strings and transmitting them.  
 
Please review my configuration and offer any suggestions.  
 
Thanks,
 
73
 
John N6VMO

-----Original Message-----
From: Earl Needham [mailto:needhame1 at plateautel.net] 
Sent: Wednesday, January 03, 2007 1:57 PM
To: TAPR APRS Mailing List
Subject: RE: [aprssig] Help with Interfacing a GPS to Kantronics KPC-3 

At 02:38 PM 1/3/2007, EXT-Maetta, John wrote:
>Hi Earl,
>
>Yep....I will worry about frequency choice and packet length, for this 
>new project, when the basics start working.
>
>Ok, I can successfully see the Xmit LED illuminate when in CONV mode.
>Text typed is transmitted, so the TNC is working.
>
>This is very frustating.  Are you using the KPC-3 with a GPS receiver?

         I have done so in the past, but it's been several years.  At
this point, you know the TNC is doing what it should.

         I'm doing all this on memory, but it seems to me that the
KPC-3 would send a blank position if it was in GPS mode and didn't get
good data from the GPS.

         Does the BEACON work?  Set BText to something or other, and B E
1 or something, and see if it automatically lights up the XMIT LED ever
so often.  Don't forget to go back to B E 0 when you're done with this
one!

         Uh -- I've already erased the original message, could you
resend your GPS settings, i.e. beacon timings, etc?

         Earl

KD5XB
Clovis, New Mexico DM84jk
http://groups.yahoo.com/group/cw_bugs
"Just say NO to DHL" 



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