[aprssig] BEACON - APRS or Not?

[William McKeehan]

Have you seen the "FAP - Finnish APRS Parser (Fabulous APRS Parser)"

http://search.cpan.org/~hessu/Ham-APRS-FAP-1.11/

If you're using Perl, it's a quick way to give your application the ability to
parse packets.

Has anyone written anything like this in Java?
-- 
William McKeehan
KI4HDU
http://mckeehan.homeip.net


On Sun, August 9, 2009 9:54 pm, Shawn Stoddard wrote:
> Lynn W. Deffenbaugh (Mr) wrote:
>> Shawn Stoddard wrote:
>>> The two stations in question are W4LAW-5 and W4LAW-6. You can see the
>>> packets on the beacons at http://aprs.fi/?c=beacon&call=W4l*&limit=50.
>>>
>>> Steve responded back with good advice: be prepared for the
>>> unexpected. As my understanding of APRS improves I have a much better
>>> idea of right and wrong. So should my parser.
>>>
>>> The question becomes do you agree or disagree with Steve's response.
>>> If you disagree, why?
>> I completely agree with Steve's response.  In my experience with my
>> own parser (adopted from the Open Source T2-135 source code), not only
>> do you have to ignore anything that may not be in the spec, but you
>> also have to be ready for some truly bizarre packets that DO have an
>> expected datatype.  There are still some Digi's out in the wild that
>> seem to be running with PASSALL (or whatever the equivalent is).  In
>> this mode, the digi/IGate doesn't care about the checksum on the
>> original packet, but rebroadcasts the corrupted contents with a new
>> checksum so later recipients can't even tell it's been mangled.
>>
>> You'll see fixed coordinates that are not even in the range of 0-90 or
>> 0-180.  So far I haven't seen one (that I know of) with the NESW
>> messed up, but I'm sure it's happened.
>>
>> For my parser, I actually log packets received from APRS-IS to one of
>> several directories.  GOOD gets the ones I'm currently handling, BAD
>> gets the ones that I'm not handling, and NOPOS gets the ones that I
>> handle, but do not have a position (like weather, messages, status, ...).
>>
>> May I ask what you'll be doing with the parsed data?
>>
>> Lynn (D) - KJ4ERJ - (No, I haven't check out the W4LAW-* stations yet)
>>
>>
>>
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> I have an interest in writing some APRS software. A good parser is a key
> component in practically any component. It seemed like a good place to
> start to build up a base of knowledge. This group has proved to be a
> good place to validate what I understand versus what the specification
> says versus what is really out there.
>
> Shawn
> KG4OVQ
>
>
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