[aprssig] RE:] APRS coverage maps for the American West

[Cap Pennell]

At http://www.bestbits.org/aprs/dv-trip-06.html you wrote:
"The way I read this data set, there were no areas where three hops were required. In each case where a packet has three hops (like the first one above), there are also one- or two-hop packets from the same initial digi (like the second packet above). This means I didn't need to use a three-hop path. Am I reading this right?"

Yes, I believe so.  <grin>


BTW, your maps are great, and they remind me of the pictures I've seen of "city lights from space", and they do indeed tend to show "where the people are" as well as where the coverage is, I think.  I can largely name the sparsely populated mountain and desert regions that show through as yellow (no posits).  If there was a way to get all the years' worth, you'd see more intrepid APRS travelers have left more tracks in that back-country, at least from the ridgetops.  Heck, crazy as it sounds, I've been known to drive to the mountain-top specifically just to get a packet out to the outside world from such a wild and faraway place!  Just ask my wife, she'll tell you I'm not alone.  hi hi

I don't know how tough it is to do, but now if you could attach a "hop-count-minimum colored dot" to each of the positions on your maps, like the old Jim KB0THN's aprsworld.net version California map, you'd have a even bigger picture.  

Then too, if I really need to get a packet out, there's the ISS passing overhead a few times a day.

Now I admit there are a few areas in South Eastern Central Nevada (and more where it's flat East of the Rockies) where you need three hops to get to an IGate, and IGate stations do go down sometimes, like digis and other stations do, so nothing's perfect.

I have an idea for more empirical testing.  Use a tracker device that can cause transmissions on a variety of digipaths and intervals, like a KPC-3 (v6.0 or greater) TNC.  Then you could transmit with NO digipath once a minute, and through one hop (WIDE1-1) once every other minute, and with two hops once every 3 or 4 minutes while moving.  Something like that would put a lot more packets into the APRS-IS without as much airtime consumption at high elevations between all the high digis that hear each other at such great distances.

Example KPC-3 commands:
BLT 1 EVERY 00:01:01 CLEAR
BLT 2 EVERY 00:02:03 CLEAR
BLT 3 EVERY 00:03:07 CLEAR
BLT 4 EVERY 00:39:55 CLEAR
GPSHEAD 1 $GPRMC
GPSHEAD 2 $GPRMC 
GPSHEAD 3 $GPRMC
GPSHEAD 4 $GPRMC
LTP 1 GPSLK 
LTP 2 GPSLK Via WIDE1-1
LTP 3 GPSLK Via WIDE1-1,WIDE2-1
LTP 4 GPSLK Via WIDE2-2

It's not the "compressed format" so the full NMEA sentences make longer-length (more air time) packets, but it can be compensated for with more variety of path and interval.


Anyway, Allan, thanks for your work and the cool maps online!
73, Cap KE6AFE

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org
> [mailto:aprssig-bounces at lists.tapr.org]On Behalf Of apratt at bestbits.org
> Sent: Saturday, May 06, 2006 22:58 PM
> To: aprssig at lists.tapr.org
> Subject: [aprssig] APRS coverage maps for the American West
> 
> 
> As I threatened to do a little while ago, I have taken three months'
> worth of data from the APRSWorld archives and used it to create
> coverage maps for California and the American West.
> 
> You can go to http://www.bestbits.org/aprs to see the results of my
> study. (Follow the "Coverage maps" link.)
> 
> The data I used is not complete: it only stores one position per
> station per hour. Also, the data doesn't support a "hop count" study,
> and I couldn't tell if any reports were from stations that were
> feeding APRS-IS directly (not over the air). You can see more about
> what I did by going to the report page on BestBits.
> 
> Thanks everybody for the help and info. Who knows? I might keep
> fiddling with this and maybe do it again for the Eastern US.
> 
> -- Allan Pratt, apratt at bestbits.org
> 
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