Today, after an announcement on his blog , SV1NJX activated briefly a balloon tracker on 433.708 kHz using CW and FSK (ASCII 7N1, 50 baud, 450 Hz) at about 08:45 UTC.
The tracker signals were of good strength but with very poor stability, with pronounced chirp in CW and gradual frequency shift on FSK. I managed to decode a few packets using my Icom IC-7100 with DL-FLDIGI 3.21.5 and with an RTL-SDR receiver with SDR# and FLDIGI 4.1.06. AFC was absolutely necessary in order to keep decoding.
$$$$SV1NJX-1,34,08:45:11,38.079212,23.881712,01054,001,0.12,43.0,06,01*82AA
$$$$SV1NJX-1,35,08:45:28,38.079308,23.881735,01044,001,0.12,43.5,07,01*87B3
$$$$SV1NJX-1,36,08:45:44,38.079281,23.881693,01056,002,0.11,44.5,07,01*E6BE
$$$$SV1NJX-1,55,08:55:02,38.079262,23.881783,01052,000,0.32,37.0,07,01*71C6
$$$$SV1NJX-1,90,09:12:02,38.079319,23.881777,01057,000,0.31,36.5,06,01*9C68
$$$$SV1NJX-1,91,09:12:18,38.079288,23.881748,01050,001,0.31,37.5,07,01*F973
$$$$SV1NJX-1,92,09:12:18,38.079288,23.881748,01050,001,0.31,37.5,00,00*7A36
The actual balloon launch will take plane in mid-July 2021.
