This is the power and frequency. So the first thing is it 2 x 40 would give a better result if you are licenced to do that. At this distance we normally get 800/800. We have links up to 8 km on Radio Waves 2’ dishes. We find the radiowaves to be excellent professional grade quality.
If you send me an email, I’ll send you a picture. But there is also even when it is running 800 x 800 it will only get about 600 MAC and it will IPERF test.
A regular signal tested speed-test will only use 1/4 of the Radio as it uses 1 MIMO. It will test 150 Mbps.
The AF24 HD if you have clear line of distance out performs 40 Mhz B11. Of course the B11 is licenced and is prone to less interference.
We have tested the real max range of AF24 HD at sea level in 80% humidity as 5 KM to get real good speed.
Lastly I would start the power at -60 and turn it up until you get 800 x 800 and then watch it in heavy rain and turn it up so it retains approx that DB. We have tuned all of ours and are not having rain fade even at 12 km. These are running at about 6dB more.