Tracker hardware is the same as B-10 and B-12.
Balloon entered saturated clouds at 8000m and seem to have picked up enough icing to cause it to descend to the Finnish-Russian border. Finnish radioamateurs organised extensive search expedition to find the balloon but sadly were not able to locate it. It could have drifted a long way at a few hundred meters over ground level from the last known position.
Search party video
Related discussion on a Finnish forum.
Payload weight - 10.4 grams.
Free lift - 3.3 grams.
Telemetry - 434.500 MHz, USB, DominoEX 16, vertical polarisation
Launch time 4 October 2013 10:00 UTC
How to setup tracking equipment
B-15 travelled over the following countries:
Big thanks to all who helped tracking the balloon!
Altitude in metres.
Great circle distance between launch site and last known position:
(C)2013 Leo Bodnar