Oh, thank you for that link! I’ve been struggling to find exactly that FCC filing :)
I’m not surprised that GSM uses higher transmit power than Iridium/Globalstar actually – GSM phones were basically portable microwave ovens compared with modern mobile radio technologies.
But if you look at the table closely, the 5G C-band frequencies have even higher power outputs than Globalstar/L-band too! That's presumably because they are so wide, though (channels in band n77/n78 can be up to 100 MHz wide; compared to > 2W for 0.2 MHz wide channels for GSM, that's nothing).
Also, for bidirectional communications path losses are usually symmetric, and since satellites are usually severely power-limited compared to terrestrial base stations, blasting dozens of watts of transmit power from the mobile device wouldn't help with receiving the satellite's response.
> Also, I'm not suggesting that the antenna is a "reflector dish" as you specified.
Ah, I misunderstood then; I thought that's what you meant by "foldable antenna". I thought phased arrays are mostly solid-state (at least they are on comparable last-gen LEO satellites). But it makes sense for Starlink to do that; every bit of antenna aperture presumably helps when trying to talk to unmodified 4G mobile devices from space.
I’m not surprised that GSM uses higher transmit power than Iridium/Globalstar actually – GSM phones were basically portable microwave ovens compared with modern mobile radio technologies.
But if you look at the table closely, the 5G C-band frequencies have even higher power outputs than Globalstar/L-band too! That's presumably because they are so wide, though (channels in band n77/n78 can be up to 100 MHz wide; compared to > 2W for 0.2 MHz wide channels for GSM, that's nothing).
Also, for bidirectional communications path losses are usually symmetric, and since satellites are usually severely power-limited compared to terrestrial base stations, blasting dozens of watts of transmit power from the mobile device wouldn't help with receiving the satellite's response.
> Also, I'm not suggesting that the antenna is a "reflector dish" as you specified.
Ah, I misunderstood then; I thought that's what you meant by "foldable antenna". I thought phased arrays are mostly solid-state (at least they are on comparable last-gen LEO satellites). But it makes sense for Starlink to do that; every bit of antenna aperture presumably helps when trying to talk to unmodified 4G mobile devices from space.