Tomasz Brol SP9UOB from radio club SP9PDF prepares a trio of balloons including amateur transmitters for launch. The first should start from Gliwice on Wednesday May 1 at 9:00 UTC. It should mainly be test (TX 437.600 MHz).
Two more balloon launches are planned for Saturday May 4 (9.00UTC TX 437.595 MHz and 10.00UTC TX 437.615 MHz).
Small 10mW transmitters will work RTTY 50 baud, 470 Hz shift, 7N1. The dl-fldigi program is suitable for decoding. You can read the program settings at http://sp9uob.verox.pl/ or http://ukhas.org.uk.