[MNAPRS] APRS issue in western MN

Sat Mar 29 08:24:01 CDT 2014

Doug,

Thanks for all of the information. I will capture the output of my TNC when
I get up to the site again.

It appears that QXM is reporting again. The local igate, NG0W-10, is down,
so QXM is being heard via a new route. I wonder if NG0W-10 might be part of
my problem too.  With NG0W-10 down, the path to an igate is longer.
Is WIDE2-1 allowing my packet to be repeated enough times to reach a more
distant igate?

I have a new antenna for the site. Waiting for the weather to improve. I am
also considering upgrading my node to an igate, but would rather leverage
existing igates.

I have spoke to the owner of the local repeater that my node announces. I
hadn't considered asking to leverage his site for APRS, but it's a great
site with great coverage.  I'll see if he is receptive of the idea.

Thanks again,

Keith
kc0zzq
keith at lakeman.org

On Thursday, March 27, 2014, Doug Reed <n0nas at amsat.org> wrote:

> You are about 55KM from QXM and about 75KM from CBV. That may be some
> of it right there.
>
> According to aprs.fi, you are on the fringe of the CBV coverage
> area and it hears a LOT of activity from Fergus Falls, Fargo,
> Detroit Lakes, and all the traffic on I-94 and Hwy 10.
>
> You are also on the fringe of the QXM coverage area, and on the far
> side of I-94 to boot. But QXM only hears about 20% as many packets as
> CBV so there is a lot better chance you'll be heard.
>
> But also remember that aprs.fi only saves and stores the FIRST
> reception report it receives. If one station has a faster network
> connection,  it might be heard first more often. And if there are
> fewer hops to the I-gate, it will be reported more often. But in this
> case, the aprs.fi data seems to indicate reception by CBV is VERY
> spotty.....
>
> So the problem could be just due to collisions with other packets. It
> doesn't really sound like a TNC problem, You are running a KPC-3plus,
> QXM is running an OpenTracker 3, and CBV is running UIDIGI on a TNC-2
> compatible of some sort. I suppose that CBV could be on a MFJ TNC and
> maybe the tone decoder needs a slight center freq adjustment? But CBV
> has the only TNC that has adjustments among the three TNCs. But it is
> seeing plenty of activity from other stations.
>
> But that doesn't explain why CBV repeats packets digied by your
> station more often than it repeats your station's own beacons..... But
> does it really?
>
> Have you actually captured the text strings from your KPC-3 and then
> actually attempted to count and compare how many times you beacon and
> CBV repeats it versus how many times you digi someone elses packet and
> your packet is the one repeated by CBV? It looks like you beacon once
> per hour and QXM last heard 18 beacons in 45 hours, with a bias toward
> hearing the night-time packets rather than daylight. There would be
> less traffic on the highway in the night.
>
> CBV only heard 4 packets in the last 4 days and there is no
> significant bias toward AM or PM hours. So QXM was hearing maybe 40%
> of your beacons but CBV is hearing less than 5%.
>
> I will frequently capture a couple days of text from my TNC so I have
> sample activity to look at. If every digi is properly doing no-wait
> digipeating as they are supposed to, it can be very difficult to
> figure out how far you are being heard, but with enough data, you can
> try....  So go through the text capture and count how often ZZQ and
> CBV appear in the same line of text. This is something you could do
> with a simple BASIC program. There may even be some existing software
> for analyzing APRS or packet traffic that might help.
>
> Overall, I don't really see any reason CBV should be hearing and
> digipeating packets that your WIDE1 retransmitted, but not be seeing
> beacons originating at your station. I guess I'd make one more change
> to your config just to see what happens. It looks like you are using
> the proper WIDE2-1 outgoing path on your beacons but CBV doesn't hear
> you well. So try changing to WIDE1-1,WIDE2-1 for a while and see what
> happens. The usual rule is that a fixed station shouldn't use WIDE1-1,
> but perhaps in this case it will improve your chances of being heard.
> I don't like the idea, but it is worth trying in case one of the
> stations in Fergus Falls hears you, or maybe KD0NEL.
>
> Have you ever done a radio coverage map of your station? You can go
> over to Radio Mobile Online, create a free account under your
> callsign, then enter in your station location as a new site. (It is
> probably best to drill down to your street by zooming and centering
> the map until you find it.) Be sure to tag it as your home station
> too, when you save it. Once that is done you can create a coverage map
> based on your station and antenna parameters. What I usually use is
> the existing antenna height, gain, coax loss, and TX power. Then
> configure the mobile as a default quarter-wave on the car roof, 2M
> height & 1dB gain, with 1 or 2dB coax loss and 1uv receive
> sensitivity. I use those numbers because they are conservative and
> will indicate less range than might actually be obtained. .
>
> The resulting coverage map will show about how far a mobile should be
> able to hear your station. The critical part here is that the coverage
> map will show you how the terrain is effecting your antenna pattern.
> If there is a ridge in one direction, your coverage will be less in
> that direction. If you are looking down a river valley, your coverage
> will be better in that direction.
>
> After you get your home coverage map working, you can add the
> locations of QXM and CBV and run coverage maps based on the info in
> their beacons. That will show you where you are from their
> perspective. If you are behind a ridge from CBV but down valley to
> QXM, that pretty well explains your problem.... It may not prove
> anything but the coverage maps can be fun to try.
>
> One simple config change you can try would be to change your beacon
> time to 3595 seconds or 3005 seconds, or some similar random
> difference from exactly 3600 seconds. Perhaps your beacon is happening
> about the same moment as someone elses beacon? I usually make a small
> change of 1 to 3 seconds on my beacon times, just to be safe.
> Actually, why don't you change back to 30 minute beacons, maybe 1798
> seconds? 30 minute beacons for a fixed station is not excessive and
> will keep your symbol on the map all the time.
>
> Overall, my guess would be that CBV is just much busier and you are
> farther away from it. If you can throw in a terrain problem, it is
> likely everything is working as well as can be expected. You might
> find significant improvement by raising your antenna another 10 feet.
> But I think what you really need is a nice high WIDEn-n somewhere
> between Wadena and Alexandria., or preferably in both cities...  :-)
> You are beaconing out two repeater frequencies. What are your chances
> of moving your WIDE1-1 to one of those sites?
>
> By the way, did you try to contact N0QXM and tell him the digi is down
> and ask when it will return? He may not know it is down, or possibly
> it will be a permanent loss..... I don't think his beacon message is
> in the correct format either, PHG is at the end rather than
> immediately after the lat-lon.....  I didn't find an email address for
> him, just a street address, and a white pages phone number.
>
> Maybe someone will have some better ideas.....
>
> 73, Doug Reed, N0NAS.
>
>
> On 3/27/14, Keith Lakeman <keith at lakeman.org <javascript:;>> wrote:
> > I'm looking for a little help in diagnosing an inconsistency I'm seeing
> in
> > APRS with my digipeater node, KC0ZZQ-5.
> >
> > My node is located near Battle Lake MN.  It's been up since last July.
> >
> > My nearest digi's are N0CBV-1 - Barnsville,MN and N0QXM-1 - Morris,MN
> >
> > N0QXM-1 has been the node that consistently repeating my node's
> > announcements.  Last weekend that node went down.
> >
> > N0CBV-1 very occasionally repeats packets that originate from my node.
>  It
> > is very consistent repeating packets that my digi has repeated orginating
> > from another node.
> >
> > I'm trying to figure out why N0CBV-1 will not consistently repeat packets
> > that originate from my node.
> >
> > Any ideas on what could cause this would be appreciated.
> >
> > thanks,
> > Keith
> > kc0zzq
> > keith at lakeman.org <javascript:;>
> >
> _______________________________________________
> MNAPRS mailing list
> Post msgs to MNAPRS at lists.twinslan.net <javascript:;>
> Sub/Unsub at https://lists.twinslan.net/twinslan/listinfo/mnaprs
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.twinslan.net/pipermail/mnaprs/attachments/20140329/5bb4b759/attachment.html>