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[aprssig] Failed APRS?

Wes Johnston, AI4PX wes at ai4px.com
Mon Jan 19 20:59:02 UTC 2009


This guy is right about smart beaconing... one of my complaints for years...
when you STOP it doesn't beacon for 30 minutes.  Smart beacon should at
least beacon as you come to rest, or preferably, go into a standard APRS
decay until the interval reaches 30 minutes.

As for trackers not being heard, Bob and I were advocating the use of
144.99mhz as an alt input frequency.  This would be perfect for the blind,
TX only trackers.  Problem is, there is not universal support for that
frequency.  It has great potential if you work out the digipeater details
that allow the 144.99 packet onto 144.39 w/o collisions!

As far as network congestion goes, I had to learn the hard way... BYOD
(bring your own digi) to your event.  We have programmed 4 D700 radios with
the SCn-n alias and are able to qsy them as needed.  We set them up in boxes
in the field with portable antennas as needed.  Back about 4 years ago, we
tried to track busses from a hospital to a shelter and found two
problems.... 1) the network was saturated (before the new wideN-N came
about) and 2) mag mount antennas don't stick well to alumium roofs on
busses.

Gale, KC4PL runs a smart digi that restricts hops, but some of our neighbors
don't.  We tried in vain to contact the digi owners and got no response
(another problem in the aprs network, errr ham radio in general - some folks
embrace new ideas more slowly than others).  I think they have at least
switched to the new widen-n system, but still don't filter excessive hops.
If anyone around central SC has checked lately, please let me know that my
facts are incorrect.

When we ran the aforementioned drill in the neighboring town, you would have
thought aprs stunk.  But one year later when we ran a motorcycle race thru a
forest with our own portable digipeaters on a frequency other than 144.39,
wow what a difference!  It worked perfectly.  We were able to use photomap
overlays and a backpack tracker that left an icon on the map to indicate the
location of problems on the race course.

Ohh... another lesson learned.  Busses at evac points like to creep forward
at, say 3mph.  Setting the smart beacon speed to 5mph causes them to be able
to travel an entire parking lot w/o triggering a transmission.  Set the slow
speed to 1mph in these cases!

Wes
---
It may be necessary temporarily to accept a lesser evil, but one must never
label a necessary evil as good.


On Mon, Jan 19, 2009 at 3:28 PM, Jason KG4WSV <kg4wsv at gmail.com> wrote:

> Sounds like this guy's biggest disappointment is that he has smart
> beaconing misconfigured, or else doesn't understand how it works.
>
> He's also guessing about congestion.  It may be congestion, or
> something wrong with his rig, or something else entirely...
>
> -Jason
> kg4wsv
>
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