820S alignment and speed question

I’m setting up my first 820S PTP. LinkPlanner shows the link should be RX -44 and distance is 4 miles. I still have to fine tune the far side on the mountain, but my RX Level are both -53 and MSE is -35 on one end and -28 at the other. When I enable Adaptive Power TX the link shows speeds as 278Mbps/345Mbps which is pretty good. However, when I run a speed test I get about 40-50Mbps.

I’m guessing that will improve when I tweak the alignment, but I’m not understanding why my speeds are so bad when the radio says the links should support much higher speeds. Can anyone help a newbie understand?

Hi Philip.

Cambium support were pretty good helping me get my first link setup. These speeds seem low but you haven’t advised what bandwidth and frequency you’re using.

IME Cambium radios’ reported speeds are accurate. I’d run an iPerf or bTest straight between both ends of these radios (laptop, rasperry pi or mikrotik at each end). You may have some sort of switch buffering issue or a faulty cable.

Under Radio->MRMC->Symmetrical Scripts ensure you’ve got the correct one chosen (mine are normally ETSI 1501) and you’ve chosen Adaptive MRMC operation mode with suitable max and minimum (10 and 0 on mine)

Ensure you’ve got the management of the radio on a different VLAN

I’m not sure if my normal config is 100% correct but they seem to work Ok!

Service ID 1 - Type PTP. Service points Radio slot 2 port 1, eth slot 1 port 1. Service type PIPE. C-VLAN-encapsulation N/A. (a.k.a. a dumb pipe)

Service ID 257 - Type MNG. Service Points Radio slot 2 port 1, eth slot 1 port 1 (I guess you could add management port untagged). C-VLAN encapsulation 2 (So VLAN2 for management)