Testing at altitude

Recently, a friend invited me to take a trip in a small aeroplane from Moorabbin to Ballarat, around 100km west of the city.  This provided the perfect opportunity to test the tracker at altitude - especially the reliability of the live imagery and telemetry.

I've put a fair bit of work into the script since the last update, which is now largely feature complete.  The results were as good as I could have hoped for - as high as 1200 meters (4000 feet), signal was patchy, but still reliable enough for live telemetry and email imagery to be sent, with strength averaging around -86 dBm (around 3-4 'bars' of reception on your average handset.)  With the use of an external antenna, I'm hoping that I'll be able to achieve reliable signal to at least 3000 meters (10,000 feet), which should see around 11 minutes of live imagery and telemetry.  Best case estimates see signal continuing to around 6000 meters (20,000 feet) - but at that altitude I'd expect only SMS-based telemetry to be transmitted.

This was also the perfect test of the KML output, which previously I'd only been able to test at ground level, which produced fantastic results:

One issue I did encounter, however, is the way in which the phone handles roaming to other networks in 'emergency calls only' mode.  The device will continue to report the signal strength of the network onto which it has roamed, rather than reporting no signal.  This causes the script to continue to attempt to send imagery and telemetry, despite the fact that it will never be received.  I believe I've found a workaround for this by checking the value returned by getNetworkOperatorName() - however this will require further testing.  Sadly, I don't think I'll have the opportunity to test this in a plane in the future!