[Xastir] Still have questions if all is working correctly

[Norman Heyen]

Thanks James, for the kind help.

I think I see what you are saying but I still don't see why there aren't
more raw packets for my station. If I look at another local station, say
N9QIP, I see there are:
(a) lots more packets sent out. I don't think he is configured to beacon
randomly every few seconds

(b) many of the packets contain station ID's where it looks like there is a
path involved. Examples are like these:
2010-05-29 00:04:27 CDT:
N9QIP>APU25N,K9ESV-3*,qAR,W9MKS-15:>221202zUI-View32 V2.03
2010-05-29 01:34:24 CDT:
N9QIP>APU25N,K9ABC-1,K9ESV-3*,qAS,K9IJ:=4320.16NI08923.41W&PHG6550/ - N9QIP
I-GATE {UIV32N}

While it looks like I'm doing my part, I don't understand why the traffic I
must be sending to APRS-IS isn't showing up. Shouldn't there be a packet
recorded for everything that I send to APRS-IS?

When I go to the 'station tracing' mode on APRS.FI (where you can hover the
mouse over a station and see the path traced out - not sure what it is
really called), I can see that several stations go from one to another and
finally terminate at my station. But there is no evidence of that in the raw
packets seen. My Xastir monitor window is pretty busy, a new line every few
seconds, so something seems to be happening. But I don't see the red
transmit LED come on.

Is it because I'm sort of isolated and there just isn't anyone else to
receive packets? It is almost like getting to APRS-IS is the end game, the
final goal. But I don't think that is how APRS is supposed to work.

Again, thanks for the detailed explanation and your patience leading me out
of the realm of APRS mystery...

73
Norman
Kc9NVN

-----Original Message-----
From: xastir-bounces at lists.xastir.org
[mailto:xastir-bounces at lists.xastir.org] On Behalf Of James Ewen
Sent: Friday, May 28, 2010 4:02 PM
To: Xastir - APRS client software discussion
Subject: Re: [Xastir] Still have questions if all is working correctly

On Fri, May 28, 2010 at 2:10 PM, Norman Heyen <n.heyen at comcast.net> wrote:

> When I look at the raw packets in APRS.FI (or any other site) all I ever
see
> are the twice per hour beacons. When I look in the station info page,
there
> isn't a section for "Stations which heard KC9NVN directly on radio". Even
> though I am acting as a fill-in in a fairly low traffic area, I would
think
> that at some point I would transmit something to someone.

You probably do send packets out onto the RF network, however you are
connected directly to the APRS-IS stream


2010-05-27 13:10:10 MDT:
KC9NVN>APX199,TCPIP*,qAC,T2MIDWEST:=4217.27N108940.67W#XASTIR-Linux-Freeport
,IL
2010-05-27 13:40:11 MDT:
KC9NVN>APX199,TCPIP*,qAC,T2MIDWEST:=4217.27N108940.67W#XASTIR-Linux-Freeport
,IL

See the TCPIP in the strings? That says that you are injecting your
packets directly into the APRS-IS stream. The APRS-IS network filters
out any copies heard after the initial packet is heard. You will NEVER
see multiple copies of a packet UNLESS something is screwed up. Copies
do end up being seen when i-gates screw up the packets by doing
erroneous character translations, a packet gets corrupted on the air,
or a Kantronics TNC running in KISS mode gets backed up and delays the
packet for more than 30 seconds before injecting it into the APRS-IS.

> There are a reasonable number of stations in the "Stations heard directly
by
> KC9NVN", that makes sense. It seems I can hear OK. I agree that I'm
hearing
> a fair number of packets and sending them to the APRS-IS (Igate?) OK, but
> shouldn't I transmit at least every once in a while?

According to what we can see, you are transmitting packets once every
30 minutes.

> Sorry if this is an obvious question but I just don't understand.

Duplicate removal... look at everyone else... only one copy of every
packet sent, but if you listen to the RF network, you'll hear multiple
copies of the packet, one for each digipeater you can hear, and
possibly the original packet heard directly from the originating
station.

It's this "clean-up" process that can lead people to believe that they
need LONG paths because their packet was ONLY heard by digipeater XXXX
located 50 miles away, or some other such excuse.

When looking at the APRS-IS stream of information you must always
remember that you are looking at a heavily filtered output stream, and
you can not base any judgements on the total health of the APRS-RF
network on just the information see on the APRS-IS stream.

James
VE6SRV
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