[Moon-net] Changing mounting plate location...?

[Jordan]

Hi...Can someone tell me if the location of the mounting plate can be changed without to much change in the pattern?

I'm trying to allow as much room above roof level for elevation and given the fact that there will be added weight to the rear section of the antenna already with the feedline, can I move the mounting plate back one element spacing...?   This would move the plate from between D-4 and D-5 to between D-3 and D-4. This would provide about 18" of extra room for elevation as well as more separation between the reflector and the roof.

Opinions most welcome...!   73...Jordan....P.S... this is for 2 meters, and possibly for K1FO 432-25 yagis...