Based on these logs I’ve worked out a way to visualise the positions received. Since then I had a 250+ mile entry appear on the coverage graph but when I checked the map there was no sign of it, so, in that case at least, I suspect it was bad data. Here’s how to do it.
Start logging the data as per the earlier posts in this thread. If you can pre-filter to log only those entries with lat/lon then even better. I’m on a Mac and I’m using the quick and dirty command below (replace the x’s with your PiAware’s IP). The grep command tells it to only log lines that have a comma followed by two digits, a dot and another digit and ignore lines that don’t have that. In and around the UK that sequence matches lines that contain a latitude co-ordinate, so only lines with lat/lon get logged. It’s a crude filter but it works. Logging is taking place to a file called log.csv on my desktop.
$ telnet 192.168.x.x 30003 | grep '\,[0-9][0-9]\.[0-9]' > Desktop/log.csv
You dont have to pre-filter the logging, it just makes things much easier in the spreadsheet later on. If you’re using Windows just log everything using telnet or Putty (see @abcd567 link earlier) or else someone else may be able to suggest a way to achieve the same pre-filtering on Windows.
Either way, the result is that you end up with a file of comma-separated logs, all or some of which have latitude and longitude entries. In my case they all have lat/lon entries because I pre-filtered with that grep command. I left this running for an hour and ended up with 63,000 lines in the log, each one being a message received with a lat/lon entry.
Next, open that file in Excel or Libreoffice and import it as a comma-separated file. Columns O and P will contain the latitude and longitude respectively. If you pre-filtered the log then every row has an entry. Select all the entries in both columns and copy them to the clipboard.
If you didn’t pre-filter then you’ll have many more lines without lat/lon and you’ll need to use the ‘sort’ feature in your spreadsheet to get all the lat/lon lines together, then copy to the clipboard as above.
Finally go to this very useful site
and click Quick MAP. In the lower left select the example entries and delete them and paste in the entries you copied. Then hit the Regenerate button and all the positions will be displayed. You can use this to scroll around and see if you can locate any distant positions which could be caused by an atmospheric effect.
(This coverage is from my mini mag mount on a coffee tin)
If I did notice a distant position of interest I would establish its approximate lat/lon from the tool here
and I would then search the orginal spreadsheet for the entry in question. That would give the date and time and ICAO so I could use FlightAware to positively identify and confirm the aircraft’s presence in that location at that time.
Suggestions for future improvement to PiAware
- Add the ability to easily log data continuously to either an attached hard drive or a network share.
- Add the ability to load a log file and visualise it on the Skyview map, being able to toggle details when zoomed in on individual entries.
- Add the ability to use this data to build comprehensive coverage maps. This wil allow individuals to start a new log when they make a site change, such as adding a preamp or changing their antenna, and visualising the difference it makes over a period of time.