Balloon Flight B-2, 2 July 2013


36" Qualatex foil balloon
Payload weight 13.4 grammes
Free lift 1 gramme
Single AAA Energizer Lithium battery
Telemetry downlink using DimonoEX 16 mode on 434.600 MHz

Results: Balloon slowly reached 6525m (21400ft) altitude and after becoming super-pressurised levelled off. However some Helium seemes to have escaped and B-2 settled into a gentle 1m/s descent ending up 50 miles NE off the UK coast probably still inflated.

DominoEX mode had great response and provided stable decoding for those who could pick up the signal. GPS-locked carrier ensured the transmitter tuning did not move more than a few Hz during the whole flight.

Annoyingly the old bug with coordinates showing zeros in seemingly random order appeared again. It can probably be traced to a routine that converts binary coordinates value into human-readable form transmitted on the downlink. Ironically both office and home location have GPS coordinates that do not expose the bug but the launch location has been affected even though it was just 500 yards from the office. After attributing the loss of coordinates to a lose contact or local RF interference, travelling back from the launch site to the office several times to fix the problem and finding that tracker was working fine the decision has been made to "just chuck it." If one imagines the Earth surface as a checkerboard where white squares are OK and black ones produce unuseable GPS coordinates and where office and home both ended up on white squares and launch site on the black one it would be easy to understand why it was so confusing when perfectly working tracker would refuse to work on the launchpad but appears to be in perfect shape back in the workshop. Well, there were worse flight control bugs than this!

Flight path:

Flight profile, altitude is in metres: