MikroTik RB941-2nD-TC low speed wifi?

Question

WiFi

MikroTik RB941-2nD-TC, 5 meters, line of sight, beeline, tariff tx 50, rx somewhere around 70, ipoe. By cable: either directly to laptops (2 different ones), or through the local port of the router - tx is at least 50Mbps. On the waffle - sometimes it drops to 5, sometimes it grows to 40, on average - 20-30Mbps. It interferes with inconstancy and jumps, causes lags. And it's just not clear why. Are the channels clogged or something is configured wrong? Could it be a marriage? What can cut the speed in the settings?

Answer 1

Most likely you did not include 40Mhz.
The settings should be like this:

/interface wireless
set [ find default-name=wlan1 ] adaptive-noise-immunity=ap-and-client-mode \
    band=2ghz-onlyn basic-rates-a/g="" basic-rates-b="" channel-width=\
    20/40mhz-eC country=ukraine disabled=no distance=indoors frequency=2472 \
    hw-protection-mode=rts-cts mode=ap-bridge multicast-helper=full name=wlan \
    ssid=Mikrotik supported-rates-a/g="" supported-rates-b="" \
    wireless-protocol=802.11 wmm-support=enabled

20/40mhz- eC or 20/40mhz- Ce depends on the channel number.
wiki.mikrotik.com/wiki/Manual:Initial_Configuratio...
eC = 20/40MHz-ht-below
Ce = 20/40MHz-ht-above
Why is the Internet speed less than the presented black...