From the website of Hans Summers (GØUPL) comes news of a 3rd balloon launch from Canada.
David, VE3KCL, used a special U3 firmware version of one of the kits available from QRP Labs and an Arduino Nano board driven by a QRP Labs Si5351A Synthesizer board. Special WSPR codes were used for vehicle telemetry which sent Callsign, Power, Locator, Altitude, Temperature, Battery, Groundspeed, GPS Status and Satellites Found. A 30m HF data download link was used with the help of a full-sized dipole hung between the system's two support balloons as well as a CW identifier on several other bands.
Hans describes the system used:
David VE3KCL launched his third balloon flight S-3 on 28-Jul-2015 at about 11:40Z. Like the former S-2 flight, this one also uses a special U3 firmware version on an Arduino Nano board, with QRP Labs Si5351A Synthesiser. Two foil "party" balloons were used, filled with hydrogen. The earlier balloons S-1 and S-2 apparently suffered burst failure before reaching float altitude due to polluted gas mix - there was a lot of propane mixed in with the hydrogen. This flight S-3 successfully climbed to almost 8,000m so this problem is now solved.
The transmission schedule includes CW on several different bands (for the reverse CW network), 30m JT9 and a special WSPR message on 30m. The special WSPR message types encodes two additional WSPR messages which contain the additional 5th and 6th character of the locator, altitude, battery voltage, temperature, ground speed, GPS status, and number of GPS satellites (a single bit, 0 means under 8, and 1 means 8 or more). The "special" WSPR transmissions therefore show up in the WSPR database with locators and powers which are not the actual locator and power, but encode the additional data. The conversion back to actual flight data is done later in an Excel spreadsheet. This is very experimental at the moment.
|courtesy: VE3KCL, GØUPL and https://www.google.ca/
|courtesy: VE3KCL and http://www.qrp-labs.com/
More information and pictures of VE3KCL's adventures can be viewed on the QRP Labs website. For those who are software-savvy, it looks like a simple system could be put together with some of the available kits.
On another note, it does appear that Andy's amazing Pico-Sat balloon did indeed go down, south of Madagascar, after almost completing its 3rd circumnavigation of the globe.