Why A single point ground panel is the place where every conductor entering the station (coax, rotator control, ladder line, phone, AC) passes through a surge protector bonded to one common ground bus. Because all the protectors share the same ground reference, a lightning surge lifts them all to the same potential at the same instant, so they clamp together rather than one firing while another sits at a different voltage. That keeps damaging differential voltages from appearing between cables inside the shack.
Watch out The idea that it prevents common-mode transients is backwards: the single point bond deliberately lets everything rise together as a common-mode event, which is harmless, instead of allowing destructive differential surges between lines.
Single point = single potential: all protectors fire together so nothing sees a voltage difference.