Help with MikroTik LHG-5axD PtP: reason code 3 and ~7 Mbps throughput

RouterOS Wireless Networking
1

Hello everyone,

I need some help with a point-to-point link using two MikroTik LHG-5axD devices.

I’m trying to build a PtP link. Initially, the distance was 8 km, but I couldn’t get the radios to connect. To validate the setup, I installed them on another link with 2 km distance.

Both devices are running RouterOS v7.21.

Current configuration

Radio 1 (AP)

SSID: pop59_51

Band: 5 GHz (802.11ax)

Channel width: 20/40/80/160 MHz

Frequency: 5580 MHz

Security: WPA2-PSK

Password: teste123!@#

Radio 2 (Station)

SSID: pop59_51

Security: WPA2-PSK

Password: teste123!@#

Issue

The Station radio can see the AP, but it fails to connect with:

reason code 3

signal -58 dBm

If I change the channel, it can connect, but throughput is very low: TX and RX around 7 Mbps.

Question

Could someone share best practices for configuring a PtP link with the LHG-5axD (especially on RouterOS v7) to ensure stability and good performance?

If possible, I’d also appreciate guidance on:

best channel width for PtP

power/antenna alignment recommendations

recommended wireless settings (mode, band, frequency, etc.)

what to check when it connects but throughput is extremely low

Thank you!

2

Did you adjust the distance property (in configuration part of wifi configuration)?

As per documentation (WiFi doc)) when unset, PtP links up to 2km will work.

As to your questions about recommendations:

  • best channel width is the narrowest which gives you required performance. Narrower channels will have better power density giving you some margin (needed in case of interference or temporary signal attenuation, e.g. in case of rain)
  • use highest power possible/allowed and align antennas as perfectly as possible
  • best channel for PtP is the one with least interference (as seen on both ends of the link) ... which might be some DFS channel (many APs tend to avoid DFS channels) but make sure there are no radars around your link (and there aren't many false detections either)
  • check signal levels ... for well working wifi link, Rx levels should ideally be between -40dBm and -60dBm ... higher than -40dBm is "screaming" and will make receiver create noise to itself ... lower than -60dBm reduces SINR and SINR defines link quality (and possible speeds). Also check channel occupation, other APs on the same channel (check whole channel width, not only control channel) will increase interference/noise and thus drop throughput.
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