[amsat-bb] Re: APRS GO-32

Robert Bruninga bruninga at usna.edu
Wed Sep 26 05:51:40 PDT 2007


> When using my D700 in TNC APRS [for GO-32], 
> the TX'd unproto looks like:
> KG4YEV to 36TYPO via 4XTECH. 
> Can anyone explain the 36TYPO. 

Yes, D700, D7 and many other devices use the Mic-E APRS format.
To make this packet as short as possible, the LATITUDE is placed
in the AX.25 TOCALL.  In this case, your latitude is 36TYPO.
Which is actually 364900.  Some of the digits carry additional
bits, and that translates them to other ASCII bytes as in the
"TYPO".  The conversion of those bits to digits of LATITUDE are:
P = 0
Q = 1
R = 2
S = 3
T = 4
U = 5
V = 6
W = 7
X = 8
Y = 9

So my LATITUDE at work is 3859.11N or can be SXUYQQ.  3 of those
extra bits are the position comment bits, one, is the N/S bit,
one is the E/W bit and one indicates if longitude is greater
than 100.

You typed that as TYPO, and "O" is not valid.  Are you sure it
was not a "0" instead?



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