From Hans G0UPL:
Big congratulations to Dave VE3KCL for the U3B-25 balloon flight
which completed its 8th lap around the world yesterday and started lap 9!
U3B-25 uses two inexpensive 36-inch hydrogen-filled balloons from China (about $15 for a 10-pack). It transmits on 20m and 30m using WSPR telemetry (telemetry protocol conceived and developed by Dave VE3KCL and Hans G0UPL).
U3B-25 is a test flight of the QRP Labs HF balloon "U3B" tracker development (see photos of an early prototype at http://hanssummers.com/balloons and scroll down the U3B-25 flight page to see actual photos of the tracker).