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[aprssig] RE: 6 meter APRS or meteorscater?

Robert Bruninga bruninga at usna.edu
Wed Dec 19 22:56:21 UTC 2007


Here is more of the idea for an APRS meteor Scatter first
response communications system:

1) I already mentioned adding 51.63 MHz receive monitors running
1200 baud APRS to many strategic Igates.  This listens 24/7 for
outgoing emergency emails from the affected area.

2) How about we use 2 meters, 147.585 at 9600 baud to throw any
emergency response traffic back into the area...

Using 100 Watts, a good beam pointed at the affected area from
about 500 miles away, and then continuously beaconing any needed
APRS one line messages back into the area at 9600 baud, would
let anyone driving around in the area possibly receive this
traffic on their D7 or D700 radios without having to keep a PC
runnning.

We have demonstrated that 6m works great, and 2m can work during
meteor scatter, so this is an area ripe for experimentation.  I
think the 6m will work fine.  But we need people to test the
success rate of forcing a message into an area using 2m.  And to
determine if 9600 baud is that much better than 1200 in this
case...  

It is the one-hand-clapping advantage of APRS that can help make
this testing more successful.  Receivers just inject into and
Igate,  Then Transmitters test at will.  When the other end
receives their packet, they can see it themselves on the
APRS-IS.  For this test, then I would receommend transmitting
every single packet with a unique serial number embedded in it
so that the APRS-IS dupe filters will not filter out all the
successes.

Any teams want to start testing?

Bob, WB4APR

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert
Bruninga
> Sent: Wednesday, December 19, 2007 5:40 PM
> To: 'Stephen H. Smith'; 'TAPR APRS Mailing List'
> Subject: RE: [aprssig] RE: 6 meter APRS or meteorscater?
> 
> >> Since Meteor scatter is a continuous statistical
> >> process, then as long as the outgoing message has 
> >> been in the TX queue for X minutes, then there is 
> >> a 99% probability that it was received and injected 
> >> into the internet.  Done.
> >>
> >> We can experiment to find out what X is.
> >> One X for using a 2 dBi gain vertical and 
> >> another X for using a small beam.  
> >
> > Huh??   How would you aim a beam at randomly 
> > occurring events? 
> 
> Say if you were in New Orleans, you would point your beam
> towards the highest density of potential listeners that are
> about 500 to 1000 miles away.  That is the optimum range for
MS.
> So I'd point towards the Eastern Seaboard.  Then hammer away.
> See my meteor.txt with the original APRSdos:
> http://www.ew.usna.edu/~bruninga/meteors.html
> 
> > I'd be ready to give this a try...here in the 
> > greater L.A. area,  weak-signal 6M receive is 
> > totally buried under 50-100 uV of lower-sideband 
> > "grunge" from channel 2 ...
> 
> You could still make a great TX site for the TX end of the
> test...
> Bob, WB4APR
> 
> 
> 
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