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[aprssig] APRS Desert?

Stephen H. Smith wa8lmf2 at aol.com
Fri Aug 27 18:32:54 UTC 2010


  On 8/27/2010 6:19 AM, Steve_wG0AT wrote:
> Did a 1000 mile road from my QTH to Kearney,NB and back yesterday. (glad I 
> don't do that often!)
>
> I was really surprised to find out that there's virtually no APRS activity in 
> NB along I-80. I saw no stations being heard on the radio stn list (VX8) and 
> for awhile I thought my radio was broken! It wasn't  until I got back into CO 
> in the range of the mountains that I started seeing call signs in the 
> calls-heard list again.  I thought I would have heard at least a few trackers 
> on RVs, trucks or hams in general along I-80 but nothing? 

Bear in mind, that simplex mobile-to-mobile range for packet on flat ground is 
only going to be 3-5 miles max. If you and a vehicle going the other way are 
both doing 75 MPH, the relative speed is 150 MPH,  You will come into the other 
car's range, and then leave it again in only 2 or 3 minutes.  If the other 
party beacons once every three minutes, you will be lucky to even 1 or 2 beacons.

> Grand Island was the only object heard/seen. Sure glad to be back in CO where 
> there's plenty APRS activity! Or so it appears?
> 73, Steve/wG0AT

I make a round-trip from my current QTH in Pasasena, CA to my hometown of East 
Lansing, MI about once a year, and pass through the I-70 / I-76 / I-80 UT-CO-NE 
corridor each time.      The APRS  "black hole" on the eastern plains of CO and 
most of Nebraska has been true for years!

It was only about 2 years ago that Grand Island even became active.   Before 
that you saw and heard NOTHING between Ft Morgan, CO and Lincoln, NE.    Even 
the vast expanses of the southern Utah desert have continuous coverage due to 
digis on 7,000 to 10,000-foot mountains.

It's the combination of very low population density -AND- absolutely flat 
terrain on the plains that kills you -- no high locations for WIDE digis.    
And of course, using an underpowered hand-held as a mobile --  you need real 
power (50 watts or more) into a decent antenna in these places.

There has been an intermittent digi for the last two or three years,  that was 
too far away to link to any others,  in the Sterling, CO area.  Did you hear it?

It is in this vast black hole area on the plains that I switch the HF rig to 30 
meters to beacon on both conventional 300 baud AX.25 packet APRS and on the new 
PSK63-based APRS.     On my trip this last May and June, not only was I heard 
consistently by igates all over the country on this band,   I actually carried 
on two-way APRS messaging with stations on both coasts with a single RF hop.

Details on HF APRS here on my website:

Conventional (AX.25 packet) APRS
<http://wa8lmf.net/aprs/HF_APRS_Notes.htm>

New PSK63-based HF APRS
<http://wa8lmf.net/APRS_PSK63/index.htm>



-------------------------------------------------------------------------------

--

Stephen H. Smith    wa8lmf (at) aol.com
EchoLink Node:      WA8LMF  or 14400    [Think bottom of the 2M band]
Skype:        WA8LMF
Home Page:          http://wa8lmf.net

=====  Vista & Win7 Install Issues for UI-View and Precision Mapping =====
     http://wa8lmf.net/aprs/UIview_Notes.htm#VistaWin7

*** HF APRS over PSK63 ***
    http://wa8lmf.net/APRS_PSK63/index.htm

"APRS 101"  Explanation of APRS Path Selection & Digipeating
   http://wa8lmf.net/DigiPaths



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