But then with the difference in distance from LEO stuff like Iridium (RIP - I actually saw the ground flash of an Iridium flare once!) you'd need a truly *massive* antenna to hear that out at geosync.
Same concept for an Iridium 9555 or its successor in a dock plugged into the small coaxial cable that goes to the external hockey puck sized antenna. This is all happening between approx. 1400 to 1700 MHz in either system.
Look up the detailed RF specs for the isatphone 2.
Both of these only work because the channel size is extremely narrow.
The antenna on the commercial satellites that do two way S/L-band to handheld stuff (or INMARSAT BGAN size terminals) from geostationary is massive, I've no reason to believe that a high budget billion dollar NSA satellite at MEO or higher altitudes wouldn't have a similarly gargantuan unfolding antenna.