In the original FX of the episode, it was not shown where the deflection beam came from and the dialogue specified multiple deflectors and not a single main deflector. SPOCK: ... activate deflectors.
Maybe they channeled the deflector power of the deflector shield generators into the main deflector to get the concentrated beam we saw?
Obviously it emanated from one central point of the ship.
In the TOS-R FX, the deflector beam is shown coming from a point next to the dish and not from the dish itself.
does this beam
come from in your opinion? I think it's rather a bad TOS-R effect that they didn't devote proper attention to.
The thing I find more confusing in this episode is that the fire up to four different phasers but all show parallel phaser beams which would suggest up to 8 phaser emitters in closest proximity...