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Sending POSIT DATA to a THD7 walkie



Here's how to send POSITIONS/STATUS data to a THD7 Kenwood HT if you are
not using APRS, but just a dumb terminal.
 
LATITUDE is encoded in your UNPROTO as follows:
 
    UNPROTO LLmm0P VIA R0MIR   for Longitudes less than 100
    UNPROTO LLmmPP VIA R0MIR   for Longitudes greater than 100
 
    Where:  LL is your latitude in degrees
            mm is your latitude minutes using this conversion:
               For the numeral 0 1 2 3 4 5 6 7 8 9
               Use the letter  P Q R S T U V W X Y
 
    Example.   For 38 deg, 45 min use  UNPROTO 38TU0P VIA R0MIR
 
LONGITUDE is encoded in the first 9 bytes of your UI packet as follows:
 
                'DM!l  -/status goes here
 
All of the first 9 bytes must be exactly as shown including the two
spaces.  The "status" can be any status text up to 20 characters.   
The "D" byte is your longitude in degrees (0-99) and the "M" byte is
the minutes (0-59) from the following table:
 
        0         1         2         3         4        
VAL:    01234567890123456789012345678901234567890123456789
CHAR:   \]^_ !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLM
        ^^^^
        5         6         7         8         9
VAL:    01234567890123456789012345678901234567890123456789
CHAR:   NOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}
 
Examples:
        For a longitude of 076deg 29min then `h9!l  -/Testing via MIR
        For a longitude of 118deg 36min then `.@!l  -/Email @amsat.org
              But in this case notice that your UNPROTO must end in PP
              to indicate that it is greater than 100 degrees.
 
NOTICE:  that the first 4 values for 00 to 03 are control chars
 
OPERATIONS:   Since every packet now contiains your LATITUDE (in the
unproto) then you must include the `LM!l  -/ at the start of your
position/status packet.  This is easy to do by putting this and your
status in your TNC BTEXT.  Or you can just type these 9 characters
at the start of each line if you want to try to communicate via the
status field.
 
DETAILS:  If you really want to be precise, this explains all the bytes:
   "0P/PP" is actually the hundredths of a minute of LAT using the same
           table.  Plus one BIT to indicate the presence of 100 Longitude.
   "`"     Identifies the packet as the Mic-Encoder compressed format
   "!"     is the hundredths of longitude using the same table.  But
           who needs accuracy to 60 feet via a satellite?
   "l  "   is your course and speed.  Here simplified to 004/000
   "-/"    is the HOUSE Icon. (just one of 350 such icons)

FOR EAST and SOUTH Hemispheres, use the actual numerals in the TOCALL
instead of the encoded ALPHABETIC characters in these places:

         UNPROTO xxxS1E VIA R0MIR

This shows you which bytes to change to numeric for SOUTH and EAST.
The 1 shows you where the "1" in 100 degrees longitude shows up by
also using numeric instead of alphabetic.

Hope this helps you to communicate with those THD7's.  Especially via MIR.
If the packets are not in this format, they wont see you.

de WB4APR, Bob




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