Change the Wi-Fi channel: 2.4 GHz or 5 GHz, which fits?

What the message looks like

Viele Nachbarnetze auf demselben Kanal, das WLAN ist langsam oder instabil, 2,4 oder 5 GHz unklar.

Common causes

• On 2.4 GHz the channels overlap. Only 1, 6 and 11 do not interfere with each other.
• Many neighbouring networks and devices use the same channel, especially in apartment buildings.
• The 5 GHz band usually has less interference but shorter range through walls.
• The router's automatic channel choice picks badly or switches during use.
• The device supports only 2.4 GHz and cannot see the 5 GHz network at all.
• Router and repeater use the same channel and interfere with each other.

Check

1. Show nearby networks, channels and bands on Windows
   netsh wlan show networks mode=bssidCopy
2. Show your own band, channel and signal strength
   netsh wlan show interfacesCopy
3. Check reachability of the router (Windows; on macOS/Linux use -c 20 instead of -n 20)
   ping -n 20 192.168.178.1Copy
4. Check whether the device supports both bands (driver info, radio types)
   netsh wlan show driversCopy

Fix

• Use the command above to see which channels your neighbours use. For 2.4 GHz pick channel 1, 6 or 11 with the fewest networks.
• Open your router's page in a browser (the address is usually on the device) and look for the section on Wi-Fi, wireless or radio channel. Names vary with the firmware.
• Set 2.4 GHz to a fixed channel and save. Then test again.
• Use 5 GHz for devices near the router, such as laptop and TV. Use 2.4 GHz for far-away devices and simple smart-home gadgets.
• If needed, give the two bands different names so you can choose on purpose. Some routers also offer a shared name, depending on firmware.
• If it does not improve, try another of the three channels and watch for a few days.

FAQ

Which channel is best?

On 2.4 GHz it is usually one of 1, 6 or 11, the one with the fewest neighbours. On 5 GHz there is more choice and automatic selection often works well.

Why can't I see the 5 GHz network?

The device may not support it, or you are too far away. 5 GHz has less range. Also check that it is switched on in the router.