My friend seems to think that the NX could use shield frequencies to disable the D but that cannot be right!
I'm not even sure what he means. I guess that he's thinking of Lursa and B'Etor's sneak attack in "Generations".
I see a few obvious flaws in that assessment:
A.) The Klingon's had an inside man (of sorts) to reveal the shield modulation. Archer would not.
B.) Archer and company are unfamiliar with shields, and thus shield modulation.
C.) The NX-01 has no shields, and a 'polarized hull' would probably not withstand a single phaser burst.
D.) The Enterprise-D, however, has been shown to laugh off attacks by primitive starships. Archer would be lucky if 'phase cannons' could peel the paint off of the 1701-D's hull.