AX won't see all wireless networks

I have a large house with a G network in the basement (Actiontec router), N network off an ethernet connected AX express on the third floor, and a G network on hte second floor off a Linksys router. Two of my AX units connect wirelessly, but neither of them see the Linksys G network on the 2nd floor. My ipad and blackberry both see the Linksys network. I've power cycled the Linksys network and its still not seen (and it is broadcasting its ID).

Thoughts?