[aprssig] APRS Meteor Scatter test!

Wed Nov 11 16:38:06 EST 2020

Scheduling and callsigns. and APRS-IS load

Yes, once we know the volunteer high power TX stations, I uess we will just
assign them one of the 4 slots.  If there are more, then we can separate
the 4 slots into regions.  THinkiong is that if say there are 4 stations in
the USA NW, SE, SW, NW, then they beam (if they have it) back to any big
pupulated region about 500 miles away.  there were some sucesses with omnis
too.

And the only stationjs that need special software are the few TX stations.

It does not make sense to beam to the middle of the coutry because there is
not a density of APRS receivers there.  Remember none of this will show up
on the APRS-is since the packet will always be captured on the first local
xmission.  Useless data.  So pick a dense populated APRS area bout 400-600
miles away.

But the APRS-IS will be loaded.  WIll this bring it down?  Or will the
first packet frame in the 15 second burst go into an IGAte and all the rest
will be ignored as dupe?  In that case it is only one packet per minute per
TX station?  But wait, Every packet will be identical so they will all be
dupes after the first.  So does this make it OK for the APRSIS?

The reason for being on 144.39 is so that no one but the TX stations have
to do anything.  Just look at their logs in the morning.

We can have 15 TX stations as METEOR-1 through METEOR-15.  More by changing
the spelling somewhat.

I thought about the problem of using a KWD radio for RX with only 100 slots
in the station list.  If that cycles through in some busy areas due to
local activity, then the meteor might drop off the bottom.  But recently I
notice traffic os down, especially if mormal people only use 2 hops.

Easy to test.  Run your radio overnight and see the date/times of all
stations in the lisrt and see if it didnt cycle to the bottom in the hours
from midnight to say 8 AM?

Bob
On Wed, Nov 11, 2020 at 11:26 AM spam8mybrain via aprssig <
aprssig at lists.tapr.org> wrote:

> Greetings.
>
> Could you clarify what this meteor mode is? I'm not sure I understand,
> between your email and the webpages.
>
> Please correct my interpretation:
>
> The station sends repeated back-to-back APRS status packets using
> Maidenhead grid locators as fast as it can for 15 seconds, then listens for
> 45 seconds, basically using timeslotting with a 1-minute cycle and 4 slots.
>
> Which part of North America gets which timeslot?
>
> If I can get this clarified, I might be able to get a meteor-mode-capable
> build of YAAC out the door by the end of the week.
>
> Andrew, KA2DDO
> author of YAAC
>
>
> -------- Original message --------
> From: Robert Bruninga <bruninga at usna.edu>
> Date: 11/11/20 04:05 (GMT-05:00)
> To: TAPR APRS Mailing List <aprssig at lists.tapr.org>
> Subject: [aprssig] APRS Meteor Scatter test!
>
> With the Leonids Meteor shower coming up in a week After Midnight next
> Monday (Tues AM), maybe its time to have some fun with APRS again!
>
> Last time we did this was 1998 and over 48 MS packets were seen over 500
> to 600 miles on the APRS channel..  Here is the report:
> http://aprs.org/APRS-docs/LEONIDS.TXT
>
> THis year I propose not a free-for-all but just a few HIGH power stations
> transmitting and everyone else in the country checks the next morning to
> see what they copied..  Best TX stations are those with several
> hundred watts and a beam.  Even one such station would be a great test,
> because on 144.39 we would have maybe 10,000 receivers. I dont have the
> power nor the beam
>
> So first, do we have any such stations?  And then We can further organize
> the test.
>
> But it would go something like this.  Say 4 TX stations around the country
> would TX a continuous keydown string of short packets for 15 seconds.  Then
> the next, and so on till the minute is up and then start again.  Xmission
> is on 144.39 national channel to maximize the number of people that might
> copy one.  Transmissions begin at midnight and runs to 6 AM.  We all wake
> up the next morning to see what we got.  Yes, this will burn the local
> channel within about 20 miles of the TX station. but since the packets have
> no path, they can only be heard in simplex range of a transmitter and
> everyone is sleeping anyway.
>
> But if a meteor happens, someone will likely capture it.  Remember, our
> own APRS stations these days only hears a packet say once ever 3 or 4
> seconds and that gives everyone a receive window of 75% of the total slots
> available.  And even if the 4 TX stations are not even synchronized it
> doesnt matter because a given meteor path only exists for a fraction of a
> second and only between two fixed 100 mile or so areas for that instant.
>
> The original APRSdos had Meteor Mode built in and did the timing and
> transmissions.  WIth a very short packet and  short TXD a single key down
> could transmit about 30 packets during each 15 second period.
>
> Any stations?
> Oh, here is the original page:  http://aprs.org/meteors.html
> Look about 75% down the page for the map of that 2m experiment.
>
> IGNORE the majority of that page.  It was showing how an emergency
> response station for example could go to an area of total devastation with
> all APRS wiped out, and with enough power and persistence could likely get
> out an emergency email message.
>
> Bob, WB4APR
> _______________________________________________
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> aprssig at lists.tapr.org
> http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org
>
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