Extremly interesting, again congratulations.
the I290 is a very good and cheaper alternative to my tracker (TK201 from http://www.mr-lee-catcam.de/pe_cc_o2_en.htm
, it costs $145).
It's not available in Italy, alas :-(
I'll have to find out if it would work with italian carriers too... Can you use any SIM card in it?
I am extremely curious about the launch parameters:
- how much did you inflate the baloon (diameter or free lift)
- what was the total payload weight? My guess is it should have been around 600 grams, if you followed the official Kaymont of a launch at 1,25 meter diameter.
also, how did you get affordable helium?
You had an ascent rate was around 6 ft/sec, much lower than I dared, for fear of battery failing before returning to earth.