Many of you may have read about the successful QSO between DJ5AR and Jan, PA3FXB using the ISS as a passive reflector, similar to airplane scatter or EME.
Using EME protocols and periods of 30 seconds, they completed the QSO using CW. This involved modifying satellite tracking software, and compensating for the Doppler shift. You can read details and hear audio files on DJ5AR's blog here:
This is quite an accomplishment, but I instantly began to wonder if it couldn't also be pulled off with much simpler equipment using WSJT software such as FSK441 (commonly used for rapidly moving meteor scatter QSO's). Doppler shift would not be a problem, even with the quick moving ISS, since the software is already optimized for short transmission periods.
It might be necessary to modify the standard messaging to allow for a complete QSO exchange to happen faster, or to shorten the periods to 15 seconds.
432 MHz has already proven to be very productive for airplane scatter, so I also wondered if 432 might be a good band for this type of experimentation. Lots of satellite operators are already equipped to operate on 432 and to track the ISS in real time with their antennas.
I'd love to hear some discussion about the possibility of this. It could open up a lot of potential grid squares on 432 and 1296 simply using FSK441.
Another problem to be solved is classifying the propagation mode in LoTW and other logging software. Would this be considered "airplane scatter" or would we have to invent a whole new name for this?
Congratulations to both hams for this accomplishment!