WiFi at 200 and then at 700m, through obstacles perhaps?

Question

WiFi

There are 3 buildings (1st - the highest point, one-story; 2nd - the second point after 200m 5-story, but the office is on the first floor, it houses the server; 3rd after 680 meters, on a hill).
There are also Ubiquiti Nanostation M2 access points.
I would like to organize ip-telephony between offices, should everything work well with such equipment, are there any nuances?
An important point, the map shows houses between our buildings, they make their way through WiFi at the moment.
It's just that there are problems with telephony in the network in the form of "stuttering" and "wheezing", but everything is fine on the server in the recording.
I sin on points and WiFi ... Unfortunately, there is no way to connect with a wire ...

Answer 1

For telephony, it is not so much the channel that matters, but the jitter, on radio links, and even with interference, it is very problematic to achieve an acceptable communication quality, depending on a bunch of factors, including the phase of the moon. Get better from any local transport provider, otherwise wheezing, stuttering, speech delay, etc. will be your constant friends. Here the problem is not in the points, but most likely in the network architecture.

Answer 2

Can scan the signal paths and select a freer channel? It once helped me to improve the signal quality. For telephony, unfortunately, I will not tell.