They made it clear that they needed to use the satellite dishes to complete the rising spell (sending the girl up to move the dish)... But we know that Morgana wanted to do this 1000+ years ago. How would she have done it when satellite dishes didn't even exist? lol. also, the new york city, 2000 shot shows a Manhattan skyline without the twin towers visible.
shareAn illustration in the Encantus shows a sorcerer performing the spell with the Merlin Circle in the sky behind him. Presumably, only Merlinians can conjure the Merlin Circle, which would be why Morgana's aerial creation was a pentagram.
I'm guessing that the satellite dishes were meant to amplify the range of the spell, sending it over the entire world instead of keeping the power local. I agree that they shouldn't be needed for completing the spell itself.