Wireless Bridge Using N type cards problems

hi there im using 2x routerboard 433AH with Os level 5 on 4.5 firmware and
2 x r52N 802.11 n radio cards.

i am setting up a wireless bridge for a back bone link whice i have succesfully done using N mode on 5ghz N only mode.
and succesfuly got a link that i can use.

but i am only getting like 50mb aggregate so about 25 each way. my test conditions are in a office with all frequancies clear no interferace. i have also ajusted the power setting.

could anyone give me some tips. i would like some screen shots from anyone else that has setup a link like this and managed to get full 200mb at worst 150mb.

thank you for any help

Do you use both chains or only 1?

thanks for the post. im using both chains. i have tried 1 as well but make no difference