> (antennas can be larger at lower frequencies without requiring steering than at higher frequencies).

No.

1. Iridium uses frequencies fairly close to GPS (~1.6GHz).

2. Iridium uses cylindrically-polarized transmissions (like GPS), which enable compact omnidirectional helical antennas

> They recently had some forays into steered, high-bandwidth antennas with their Certus line and their second-generation satellites that now allow native packet switching (the first gen was circuit-switched at 2.4 kbps only), but that brings you into the bandwidth-limited regime,

This is AI slop?

No, the point of using an electrically-steered beam antenna is that it improves SNR, so that you are not bandwidth limited.