Omni interference?

We have our 900MHz AP’s on the same platform as an omni. Would this intefere with our transmission and if so, how far away do we need to be?

If the omni is in the same band and powerful enough then yes it can cause interference. The best thing to do is run the spectrum analyzer to check your noise floor and then determine what distance you need to be. Keep increasing until the C/I is good enough to efficiently pass data.

Its tough to tell how far you need to be without knowing the actual data.