Also these guys will like it: OK - different modulation, simpler, but a predecessor of the LoRa-fied RFM9x (SX1276…) , the RFM22 (Si44xx) took years ago even space as challenge several times for a longer distance (but extra LNA) - I guess they report how these SX127x spread-spectrum RF ICs perform on upcoming CubeSats:
Out of the 4 PQ “veterans” in space, at least 2 ($50Sat and T-LogoQube) are known to have used the HopeRF RFM22B radio module. This is a tiny 16x16mm RF tranceiver module, that is capable of +20dBm output (That’s 100mW for those that haven’t googled it yet), in the UHF frequency range. It is based on the Silicon Labs Si4432 Radio IC. Despite the seemingly limited power output, some of the data types can be detected almost horizon to horizon - approx 2900km range! Data packets can also be decoded at up to 900km with just a 10db gain Yagi and a LNA. Not bad for a sub $25 radio module!!!
BTW: for those who need to calculate RF distribution, laforge wrote a RF coverage/path loss -plugin for gnumeric (Free Space; Egli; Hata (open space); Hata (suburban); Hata (small city); Hata (medium city); Hata (large city)).