APRS Performance Report from the Colorado Plains

[grenwis]

Yesterday I flew from Denver to Colorado Springs, but I also went East over Limon. The country around Limon is such that you'd have trouble hitting something if you landed blindfolded. That said, the performance of the Micro-Trak 300 was impressive. It looks like it missed only a point or two over the 1.7 hour flight, and some of the receptions were from 180+ miles away. This is with the J-pole antenna's middle taped to the center bar of the canopy and the sides loosely taped to the canopy insides.

Here's the link to the track:
http://aprs.fi/?call=ka4hrd&mt=m&z=11&timerange=10800

Does anyone know how to get a listing of data points that includes speed, heading, altitude, lat, long? Clearly it is in the data packet being plotted, but how can we see it?

In case you're wondering, I flew to Meadow Lake for a visit and then I decided to run one wing tank dry over an airport (Limon) so I could calibrate my fuel level in my new Dynon EMS-D120. I went through the calibration filling procedure at Front Range after landing.

Rick Grenwis
RV6AQB 200 hours

[petehowell]

The techy gurus hopefully can get the data for you. Here is my first attempt at a sky write.

R for Ryan, K for Kate. Clearly more work to be done:

[Davepar]

In theory, you should be able to download the position data from findu.com with the following URL:

http://www.findu.com/cgi-bin/posit.c...t=24&length=24

where the start and length parameters are in hours. Replace "posit" with "rawposit" if you want to see the raw APRS packets.

However, I cannot get this to work for Sam, Pete, or your tracks. I don't know why. It works fine for other IDs like:
http://www.findu.com/cgi-bin/posit.cgi?call=ki6ils-9

I'm a bit baffled by it.

Actually, I just found another path to the raw data:
http://aprs.fi/?c=raw&call=KA4HRD

[kevinh]

Here are the docs on all the structured cgi queries. Wow - runwayfinder + aprs would be great...

http://www.findu.com/cgi.html#wxxml

Dave - I think the reason it may have not worked for some is the choice of the start parameter. Just pick something big:

http://www.findu.com/cgi-bin/posit.c...ii-1&start=120

[Davepar]

Doh! I get it now. "Start" is the start going forward. I was thinking backwards.

Rick, you can find your positions with http://www.findu.com/cgi-bin/posit.c...4hrd&start=120

[bigbill25]

I am looking into a way to convert the comma separated variant of that file (http://www.findu.com/cgi-bin/posit.c...time=1&comma=1) into a .gpx file so it could easily be used to geocode photos, load into other GPS receivers, etc. Currently having problem converting the YYYYMMDDHHMMSS data format...

--Bill

[bigbill25]

OK, I think I figured it out.

First, you need to get your data. We will use the CGI at findu.com that Dave found. Here it is:

http://www.findu.com/cgi-bin/posit.c...time=1&comma=1

Now, after the '?', there are a couple parameters you need to set:

• call - This is your call-sign. In my example, I used Rick's
• start - The number of hours before now that you want to start fetching data. I am writing this on March 20th and want to grab Rick's flight from March 18th, so I used 72 hours to be sure
• time - This just needs to be a '1' to get a time stamp
• comma - This just needs to be a '1' to get text back rather then a HTML file

After you run this URL, you will get something like the following:

20080318220359,39.25100,-103.62583,327.0,141.0,9561
20080318220423,39.26033,-103.64033,297.0,136.0,9436
20080318220503,39.27367,-103.66817,303.0,132.0,9374
20080318220543,39.28717,-103.69650,299.0,154.0,9328
20080318220622,39.30100,-103.72733,303.0,147.0,9354
20080318220702,39.31600,-103.75533,304.0,141.0,9377
20080318220742,39.33117,-103.78250,304.0,135.0,9164
20080318221101,39.41033,-103.91333,308.0,135.0,8491
20080318221419,39.48983,-104.04150,309.0,136.0,8524
.
.
.

Copy all of this data and put it into a new text file (with notepad.exe or whatever you have handy for such purposes). Save the file and remember where it is.

Now, start GPSBabel (Download and unzip it if this is your first time) by running GPSBabelGUI.exe.



Make sure

• Input Format is set to "? Character Separated Values"
• Style is set to findu.style (see below)
• Input File is set to the text file you saved above
• Output Format is set to "GPX XML"
• Select an output file to save to
• Only have the "Tracks" box checked

Here is the findu.style that you will need for this input. Copy it and save it as findu.style:

# Format: findu.com APRS track via http://www.findu.com/cgi-bin/posit.cgi
# CGI Usage: http://www.findu.com/cgi.html#posit
# Author: Bill Anderson
#   Date: 03/20/2008
#

DESCRIPTION  findu.com APRS Track
EXTENSION    csv
DATUM        WGS 84
DATATYPE     TRACK

#
# FILE LAYOUT DEFINITIIONS:
#
FIELD_DELIMITER COMMA
RECORD_DELIMITER NEWLINE
BADCHARS "

#
# INDIVIDUAL DATA FIELDS, IN ORDER OF APPEARANCE:
#
IFIELD GMT_TIME, "", "%Y%m%d%H%M%S"
IFIELD LAT_DECIMAL, "", "%f" # Latitude
IFIELD LON_DECIMAL, "", "%f" # Longitude
IFIELD PATH_COURSE,"","%f"
IFIELD PATH_SPEED_KNOTS,"","%.1f"
IFIELD ALT_FEET,"","%.0f"

Get this dialog by clicking on the Input Format Options button. Make sure you have the findu.syle file in the last option. Click OK to close.

Click the "let's go" button, and it's done!

Now, you can use the created .gpx for a lot of stuff. You can load the track up to a GPS receiver so you can re-fly it. You can use it in a program like GeoSetter (free) or RoboGEO (no so free) to geocode the pictures you took while flying...

Hope that is of value to someone!

Assumptions: Time is UTC, Map Datum is WGS-84, Speed is in Knots, Altitude is in Feet

--Bill

[Sam Buchanan]

Originally Posted by bigbill25

OK, I think I figured it out.

Now, you can use the created .gpx for a lot of stuff. You can load the track up to a GPS receiver so you can re-fly it. You can use it in a program like GeoSetter (free) or RoboGEO (no so free) to geocode the pictures you took while flying...
<big snip of great info>
Hope that is of value to someone!
--Bill

Bill, really cool stuff! It'll take me a little while to work through this.

Can the data be loaded into MS Flight Sim so the flight can be flown/reviewed?

(Yeah, I know, a little juvenile, but hey.......)

[L.Adamson]

Originally Posted by Sam Buchanan

Can the data be loaded into MS Flight Sim so the flight can be flown/reviewed?

(Yeah, I know, a little juvenile, but hey.......)

That's okay...........

As a whole lot of commercial, military, and GA pilots mess around with MS Flight Sim too...

In reality, the topography data (as in mountains) of today's desk top flight simulations is very accurate; and makes them benefical for pre-flying to un-familiar areas. Someday, even the synthetic vision MFD's will look as good!

L.Adamson

[grenwis]

Thanks Bill,
I can't believe I didn't think of that. hahahahahahahahahahahahaha

I'm not even sure why I asked for the raw data now, but it might be interesting to play with. Thanks for all the effort.

Rick