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DECODE_APRS(1)		    General Commands Manual		DECODE_APRS(1)

       decode_aprs - Convert APRS raw data to human readable form.

       decode_aprs [ text-file ]

	      text-file	 should	contain	AX.25 packets in the standard monitor-
	      ing format or as a series	two digit hexadecimal numbers.	If the
	      first  number  is	 00 or c0, it will be treated as a KISS	frame.
	      If no file specified, data will be read from stdin.

       decode_aprs is useful for understanding sometimes obscure APRS  packets
       and finding errors.


       You see something like this show	up on your screen:

	      M0XER-3>APRS63,WIDE2-1:!/4\;u/)K$O J]YD/A=041216|h`RY(1>q!(|

       What  does  it  mean?   If you haven't spent a lot of time studying the
       APRS protocol specification, most of  it	 probably  looks  like	random
       noise.  Pipe it into decode_aprs	to find	out.

	      echo			   'M0XER-3>APRS63,WIDE2-1:!/4\;u/)K$O
	      J]YD/A=041216|h`RY(1>q!(|' | decode_aprs has a  never-ending  collection
       of  packets  with  errors.   Sometimes it's  not	 obvious what is wrong
       with them.  Dire	Wolf will usually tell you what	is wrong.  First, cut-
       n-paste the bad packets into a text file.  Here a few examples:


	      K0YTH-10>APNU3B,NULL,qAR,K0DMF-10:!4601.5NS09255.52W#PHG6360/W2,MNn 444.575

	      00 82 a0 ae ae 62	60 e0 82 96 68 84 40 40	60 9c 68 b0 ae 86 40 e0	40 ae 92 88 8a 64 63 03	f0 3e 45 4d 36 34 6e 65	2f 23 20 45 63 68 6f 6c	69 6e 6b 20 31 34 35 2e	33 31 30 2f 31 30 30 68	7a 20 54 6f 6e 65

       If  you	simply	fed  this  into	decode_aprs, it	would complain about the
       lower case in qA-something, added by the	IGate, in the via path.
       We can take it out with something like this:

	      cat findu-errors.txt | sed -e 's/,qA.*:/:/' | decode_aprs

       In the first case, we get,

	      Address has lower	case letters. "n2cma" must be all upper	case.

       After changing the source address to upper case,	there are other	issues.	 Identifying them is left as an	exercise for the reader.

       In the second example,

	      Invalid character	in latitude.  Found 'N'	when expecting 0-9 for hundredths of minutes.
	      Invalid character	in longitude.  Found '9' when expecting	0 or 1 for hundreds of degrees.

       In the third example,

	      Warning: Lower case letter in Maidenhead locator.	 Specification requires	upper case.
	      Digi2 Address, " WIDE2-1"	contains character other than letter or	digit in character position 1.

       More   detailed	 information   is   in	 the  pdf  files  in  /usr/lo-
       cal/share/doc/direwolf, or possibly /usr/share/doc/direwolf,  depending
       on installation location.

       Applications  in	 this package: aclients, atest,	decode_aprs, direwolf,
       gen_packets, ll2utm, log2gpx, text2tt, tt2text, utm2ll



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