[Xastir-dev] understanding APRS messages from xastir

[Kristoff]

Hi Tom,


Thank you for the very quick reply. :-)


I thought I was lucky as I managed to find just one single document that 
contains all specs of a protocol in one place (which is a rarety in the 
amateur-radio world)


looks like I have some additional reading to do. :-)




73
kristoff - ON1ARF



On 27.10.21 00:04, Tom Russo wrote:
> I should note that while APRS101 is the official "1.0" spec, it has been
> set in stone since 2004, which is so long ago that APRS has had many, many
> additional hacks tacked on since.  Creating the 1.0 spec was a herculean effort
> that never got repeated for subsequent revisions.
>
> These tend to be found only in Bob's "addenda" pages and in discussions on
> APRSSIG, but many of them were so good (like reply-ack) that they really are
> implemented by most codes.
>
> You can find the "1.1" and "1.2" addenda on Bob's web site, http://aprs.org/
>
> http://aprs.org/aprs11.html
> http://aprs.org/aprs12.html
>
> On Tue, Oct 26, 2021 at 03:59:10PM -0600, we recorded a bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
>> This is the "Reply-Ack" feature.
>>
>>
>> It's not part of the 1.0 APRS spec, it's in one of Bob Bruninga's "addenda"
>>
>> http://www.aprs.org/aprs11/replyacks.txt
>>
>>
>> The short story is that it improves messaging, because the reply to a message
>> contains an "ack" of that message.  This is just in case the real "ack" got
>> lost.
>>
>> On Tue, Oct 26, 2021 at 11:56:22PM +0200, we recorded a bogon-computron collision of the <kristoff at skypro.be> flavor, containing:
>>> Hi all,
>>>
>>>
>>> I am working on a project to extend the firmware of the TTGO
>>> (aprs-over-LoRa) iGate software.
>>> https://github.com/on1arf/LoRa_APRS_iGate
>>>
>>>
>>> I am currently doing some additional work on the APRS-IS to RF gateway,
>>> specially for APRS "Message" packets.
>>>
>>>
>>> I am using xastir on my linux laptop to test out my code.
>>> (my igate has ON1ARF-12, my linux laptop/xastir has ON1ARF-14)
>>>
>>>
>>> A test message I received is this:
>>>
>>> ON1ARF-14>APX215,TCPIP*,qAC,NINTH::ON1ARF-12:test 1.2.3.{3y}12
>>>
>>>
>>> Can somebody help interpret this message?
>>>
>>> Looking at the "APRS 101" document (which I guess can be considered to be
>>> the more-or-less official specification for APRS), this seems to be a normal
>>> "Message" APRS-message, with message identifier (which should be
>>> acknowledged by a reverse "ack" message).
>>>
>>> But as I had just previously received a "ack12" in a previous message from
>>> the xastir station, it looks like that the "{12" is in fact a repetition of
>>> that.
>>>
>>>
>>> So, can I interpret this message as a combination of two messages: "test
>>> 1.2.3.{3y" and "ack12"
>>>
>>> I do not find anything in the "APRS101" document (version 1.0.1 d.d. 29 Aug
>>> 2000) that describes this kind of "two-in-one" messages.
>>>
>>> So, I am a bit confused why xastir sends this kind of messages packets.
>>>
>>>
>>>
>>> Can somebody shed some light on this?
>>>
>>>
>>> 73
>>> kristoff - ON1ARF
>>>
>>> _______________________________________________
>>> Xastir-dev mailing list
>>> Xastir-dev at lists.xastir.org
>>> http://xastir.org/mailman/listinfo/xastir-dev
>> -- 
>> Tom Russo    KM5VY
>> Tijeras, NM
>>
>>   echo "prpv_a'rfg_cnf_har_cvcr" | sed -e 's/_/ /g' | tr [a-m][n-z] [n-z][a-m]
>>
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