Path Loss for 239,000 miles at 436.4 MHz = 197 dB. Tx output is 2W (+33 dBm) thus signal at earth will be +33 dBm-197 dB = -164 dBm. With a 20dBi gain antenna that is -144 dBm... a very weak signal. I'm not up to speed on digital signals like "GMSK with 1/4 turbo code and 250 baud GMSK with 1/2 turbo code, etc." but I think this path pushes the limits a bit whenever the satellite is near Apogee. Then again, the satellite may have some gain on 436 MHz thus improving the link budget by 3-7dB. I didn't see any satellite antenna gain or EIRP figures online.
If you're interested in this mission, the place to be is Twitter (in fact, many of the hard core ham radio experimenters hang out on Twitter). Here's some folks to follow. https://twitter.com/bg2bhc https://twitter.com/coastal8049 https://twitter.com/ea4gpz https://twitter.com/uhf_satcom
