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

Lynn W. Deffenbaugh (Mr) ldeffenb at homeside.to
Mon Apr 20 11:54:50 EDT 2009


I wasn't sure what days I was after, so I graphed the data that I have.  
You can view it at


I didn't try to analyze it in detail, but the packet on the 18th that 
shot from South Carolina to central Florida was pretty wild.

Also, I believe my server was down for several hours somewhere over 
those days, so a lack of visibility on the map doesn't necessarily mean 
a lack of coverage...

Lynn (D) - KJ4ERJ

PS.  Feel free to pull these graphs for any use, but please don't link 
to them as my outbound bandwidth isn't that great.

Rich Garcia wrote:
> 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
> in
> 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.
> Rich
> -----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
> digis.
> Enjoy.
> Bob, Wb4APR
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