Hi Guys.

We are seeking to create a wireless wide area network in an area that is saturated in wireless ubiquiti antennas. We have tried our own ubiquity antennas and have discovered that there is way too much noise in the area for the equipment to function properly.

The areas that need to be connected are approximately 4km apart.

What are the possible options for connecting these two locations in a way that would be robust enought to handle VOIP phones ?

I take it you did your research and now realize 2.4GHz links are impractical and noted widely such as https://en.wikipedia.org/wiki/Long-range_Wi-Fi

Since you want ROBUST then you must over design the link to be something for 10 to 20 KM distances.

Since this is an area of OVERCHOICE, you need to talk to the makers about possible solutions like https://www.balticnetworks.com/ubiquiti-airmax-5ghz-ptp-super-long-range-link-kit.html but once in a while I'll see a client that has no IT staff or networking skills trying to install this. They fail everytime. For those folk, get it done by a local networking company or even Cisco.