[UAT] Dan's Software help

[Basil Gunn]

> Hi again, Erik
>
> I am not absolutely sure, but I believe you're talking about the
> THIRD PARTY FORMAT of aprs packets:
> "One special format character } allows any APRS packet to be carried
> or transmitted by any other station. This is what allows the both the
> ZIPLAN and IGATE messaging capability! On receipt of a 3rd party
> packet, the original header is dropped and the packet is recursively
> parsed again, beginning at the {."
>
> Parsing of such packets is not (yet) implemented by libfap,
> unfortunately. I believe n7nix's branch tries to handle this but
> relies on a libfap patch that has not been accepted yet (correct me
> if I'm wrong).
>
> --
> 73 de LA5NTA

Erik, LA5NTA,

The n7nix branch uses a modified fap parser to be able to handle third
party/encapsulated packets. It's a very simple change that just
returns a packet type of fapTHIRD_PARTY. dantracker code then parses
to the start of the encapsulated packet and resubmits the encapsulated
part to the fap parser just as LA5NTA describes above.

I need to handle third party packets because I'm using dantracker to
send/receive APRS messages.

I've sent a couple of e-mails to the guy (oh2gve at pakettiradio.net)
that I think supports fap with no response. Not sure if I have his
correct e-mail address or if he's too busy to respond.  I will check
in a patch to fap parser in the n7nix branch later on today.

The primary difference between the original code from Dan KK7DS is
that the n7nix branch supports viewing dantracker on a web browser. My
vision is to be able to send text messages (APRS messaging) and e-mail
(paclink-unix) from any WiFi capable device through my 2m or 440 HAM
radio. My mobile setup includes a prototype ARM cpu card that runs
dantracker, paclink-unix and hostapd access point. I use an Android
Nexus 7 as my viewing/sending device.  A requirement is that the
browser has to be web sockets compatible
(http://caniuse.com/websockets).

The n7nix branch will probably never merge back with Dan's original
code.  When I started making changes to Dan's code I wasn't very good
at checking in small atomic changes so the n7nix branch quickly
diverged from the original code.

Current list of differences between n7nix branch & original code.
- Uses web browser for display
- Parses encapsulated packets
- Enables APRS messaging
- Includes packet spy app
- Includes simple fap parser packet verifier app.
- Uses AX.25 protocol stack
- Packet statistics display
- Packet capture in spy, replay in spy or dantracker apps

If you look at aprs.fi, n7nix-3 is a continuously running dantracker
on my workstation, n7nix-12 is my mobile dantracker in my truck,
n7nix-1 is my aprx iGate.

I've been having fun working on and using dantracker since last December.
Big thanks to Dan KK7DS for making his code available.

/Basil N7NIX