[aprssig] AL, GA, TN, VA APRS network Reliability

Rusty Hemenway nnn0fjk at gmail.com
Sun Apr 19 09:13:18 EDT 2009

I just made a trip from Southern California to Atlanta GA via I10 to I20.
Good APRS coverage in the West, poor in Alabama and Mississippi. I went
quite a while between hitting digi's.  


-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Rich Garcia
Sent: Saturday, April 18, 2009 8:24 PM
To: bruninga at usna.edu; TAPR APRS Mailing List; 'Lynn W. Deffenbaugh (Mr)'
Subject: Re: [aprssig] AL, GA, TN, VA APRS network Reliability

I know the message is old but I wanted to comment on this since I did
something similar and have been trying to decode the data as best as
possible for the past hour which is difficult since I don't have a huge high
speed pipe. My high speed connection here is a very weak EVDO modem
servicing the house, more like DSL "lite" speeds.

My trip started Tuesday from the Charlotte NC area to Gatlinburg /Pigeon
Forge TN via I-85 to I-26 and I40, then it was off to Nashville TN via I40.
I spent 2 days there then back tracked I-40 to I-81 Bristol then I-77 near
Bluefield/Princeton WV for the day and I just came back home via I-77 into
NC and finally at home in SC.

All in all it seemed that APRS coverage was good except south and north of
Asheville along I-40 and then it was very poor once I passed Bristol TN and
got into the area of the I-81 I-77 interchange. I know there are issues
between digis in the VA/WV/NC area I think that follow the old WIDE and the
newer WIDE-n but I also often changed between the two on my D700 but still
no dice, no coverage.

I am trying to figure out exactly what is going on, I think it's a
topographic problem considering all the tall ridgelines and peaks in the
area AND also a mix of Alias settings and locations of Igates vs digi's.
Even though we have some major highway's in the area the population density
is very light and digi's/Igates are not in the best area. KD8HE is a I-Gate
Beckley WV and also a WIDE, I am taking a wild guess at an older KPC-3 at a
home station. There is a digi further north which is also an older WIDE and
I do not belive heard by anything except KD8HE.

The I-81 I-77 interchange has got to see several hams a day cross the area,
it's a busy region for highway travelers. Looking at APRS.FI I would have
never thought that Beckley WV would have seen a lot of APRS activity but
today alone me included there were 3 APRS equipped hams, that is a lot for a
rather small WV coal town!

A digi closer to the I81/I77 split is really close but I think on the wrong
side of the mountian and offers no coverage as far as I could tell, one or
two packets that did make it to the APRS IS today from me was from a digi
4x+ the distance away and quite spotty as can be expected. I am guessing
that it has good coverage to the east side towards Roanoke and needed but
it's leaving the west side, Wytheville/Princeton area really naked for a
digi and the only I-gates are too far away in Roanoke and Beckley.

I know a ham in the area who may be able to contact the powers that be and
get some action going. Honestly I think the equipment was installed YEARS
ago to help the region but I don't think very many if any people use APRS
other than the travelers that cross those roads on a daily basis. The
digi/igate owners may not even have any idea of what is going on and the
changes that have happend over the past several years. It's a 3.5 hour drive
for me but I am willing to go up there for a day or two and help out if
invited to do so. I may even have some extra commercial gear here to put
towards the cause if a few good sites can be found for some additional
digi's. With those mountians and roads I doubt there can ever be 100%
coverage but improvements can be made with some luck and effort.

Lynn could you make heads or tails any better of this using one of your
maps? I would say my setup is average or a bit above with a D700 on high
power, a low loss NMO through roof mount and a gain antenna on a rather
large high ground plane (Expedition). If I were getting those results I can
just guess how the coverage would be for a tracker and magnet mount setup.


-----Original Message-----
From: Robert Bruninga [mailto:bruninga at usna.edu]
Sent: Wednesday, January 21, 2009 5:50 PM
To: 'Lynn W. Deffenbaugh (Mr)'
Cc: 'TAPR APRS Mailing List'
Subject: [aprssig] AL, GA, TN, VA APRS network Reliability

For Alabama,Georgia, Virginia, North Carolina, and Tennessee:

Here are two maps (1 meg each) of my 50W APRS D710 mobile
between N.Alabama and Wash DC through AL, GA, NC, VA and MD.  I
was running proportional pathing, so direct lines to Igates are
every 1 minute (rare) but red lines via a digi (1 hop are every
2 minutes) and those that took two hops, red-then-green were
once every 4 minutes.  Path Tracing by Lynn Deffenbaugh KJ4ERJ.

See:  www.aprs.org/I-81virginia.PNG

I-66 from DC to I-81 and down to Harrisonburg was very good.
I-81 Harrisonburg down past Lynchburg to Roanoke was poor
I-81 Roanoke to Bristol was very good.

See: www.aprs.org/AL-GA-TN.PNG

Alabama(north) track was very good.
Tennessee: I65 Lawrenceburg to Columbia was poor
Tennessee: I40 Nashville to Knoxville was very good
Tennessee: I40/81 from Sevierville to Bristol was poor
Georgia:  Blairsville to Dalto to Chatanooga was poor
North Carolina: North Georgia through Ashville and I26 to
Elizabethtown was very poor

The ray-tracing also gives very good coverage plots of some

Bob, Wb4APR

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