[aprssig] Another 60 Meters APRS Test This Week: Tuesday 26 June - Thursday28 June

Stephen H. Smith wa8lmf2 at aol.com
Mon Jun 25 10:29:20 EDT 2018

On 6/25/2018 5:31 AM, Miroslav Skoric wrote:
> On 06/25/2018 08:13 AM, Stephen H. Smith wrote:
>> After the screwup last weekend due to a flakey driver for the uBlox GPS I was
>> using (which caused me to appear to have never left home), I am trying 60 
>> meters
>> APRS again this week.
> Regarding uBlox chip -based GPS devices: I was recently done some APRS tests 
> in Rabat, Morocco, and I had a Taiwanese G-mouse having an uBlox chip. But 
> something caused me to appear on the map some 1500-2000 km to the east 
> (somewhere near Algerian-Tunisian border). Any idea what might have happened? 
> And when I returned back to Europe, everything was fine again with reporting 
> my locations. (The same hardware & software used. The software is dxlAPRS by 
> Chris OE5DXL.)
> Misko YT7MPB 

Were you seeing the error on your own computer & display,   or was it on APRS 
displays on the Internet?

In Rabat, you would have been west of 00 00.000 longitude, while most of Europe 
is EAST of the prime meridian (i.e. positive longitude).    In the past, I have 
observed some mis-configured igates running buggy software in southern Portugal 
and Spain passing trash into the APRS Internet System,  when mobiles would go 
west of 00 00.00 longitude.  (Apparently had problems with negative values of 


In my case, the u-Blox driver problem was quite different.   After running 
constantly for  a day or so, the GPS suddenly reverted to reporting  my start 
location (where the device had been powered-up) instead of my current 
location.   The driver did NOT lock up or crash -- it just started reporting my 
initial home location instead of the current one.   The applications using the 
data kept accepting the position as valid.  There were no "Invalid Position", 
"No GPS Fix",  or"Los of GPS Data" -type error messages.

Normally, I would have noticed something was wrong by seeing my own position in 
the wrong place on a map display.   But in this case (experiments on 60 
meters), I was running running APRS Messenger blind as a transmit-only tracker 
without a mapping display in the car.   As a result, I did not discover the 
problem until a day later when I started checking my home display and APRS 
mapping sites like APRS.fi .

Tomorrow, I WILL be running a mapping display in the car, so I can spot such an 
error and reboot the system, if needed.


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