That will be too low. The foliage and obstacles cause huge attenuation. My link is pretty clear. The AP is 100 meters high on a hill, while the client is on a platform at the other side. They...

Channel interference. Try different channels and use channel width 20MHz (HT20). Also, if you are using 7210 as a AP client router, it is a client device, you should both ends to ensure a stable...

AP ))) ((( Client ---------wired-----------router or AP ----LAN ...........................................|<--- inside your house -->|

Believe me, you should choose CPE510. 5GHz is always better than 2.4GHz for outdoor communication of long distance when line of sight is ensured. I have two CPE510 working as a point to point link at...

Is the static WAN IP a public IP address?

Sounds like a power adapter issue? Have your tried plug it into another power outlet? If the noise still remains, you'd better contact the shop for replacement under warranty.