We (Westbury Park Primary School Coding Club) are hoping to launch an 800g balloon this weekend, with 300g payload comprising 2 GPS radio trackers, LoRa and RTTY, with SSDV on the main tracker. Estimated burst altitude is 34-36km and the general direction of the flight is currently predicted to be SE towards Shaftesbury.
The main tracker is on 434.225MHz, payload ID AETHER, LoRa Mode 1, telemetry and SSDV.
The backup tracker is dual LoRa and RTTY, with loRa on 434.450MHz Mode 1, and RTTY on 434.400MHz, 300 baud 8 N 1, 440Hz shift. Telemetry only no SSDV. The tracker generally sends a couple of packets on LoRa then a couple of RTTY, but periodically it also sends out a calling mode message (433.650MHz mode 3). For RTTY you'll probably miss the start of the first packet as the decoder wakes up, but the second packet should be fine.