I currently have Ubiquiti AirMax nanostations, three years old. They seem to be failing for sending wifi to my work shed 600 feet away. I have an AP at the house sending signal to an AP at the shed, connnected to a router for the wifi signal out there. I am looking to replace these APs. Should I use TP Link APs or is there one extender that will work? I need signal inside and around a metal building out there. All components should be rated for outdoor. Thanks!