Failure to maintain chosen WiFi connection.

[jayess]

I have been discussing a problem with a friend who operates a Macbook (High Sierra). This computer changes from the 2.4 GHz to the 5G Hz band of its own volition whenever the mac is woken from sleep. Does anyone have an explanation for this behaviour? Where do you think we could start looking for a fix?

 

[Howard2k]

Assuming you have the same SSID on both, your MacBook is supposed to select the best choice based on various criteria such as signal strength, noise, and hopefully other factors.

I keep my 5Ghz and 2.4Ghz networks with separate SSIDs so I can put different devices in different spaces. I then manually select the 5Ghz channel or the 2.4Ghz channel.

 

[RichardF]

Ditto.

But my MacBook Pro does this even if I have a different SSID (but the same password) for the 2.4GHz and 5GHz broadcasting (NETWORK and NETWORK5).

I believe it's all in the keychain.
I did "forget"/ delete the 2.4GHz SSID from the Settings in macOS but the MacBook Pro reconnected to it anyway.

Perhaps starting with a clean/ bank keychain would solve it?
There is so much in there, I have not taken the step to back up and create a new one yet to test this hypothesis.

 

[tromboneaholic]

Assuming you have the same SSID on both, your MacBook is supposed to select the best choice based on various criteria such as signal strength, noise, and hopefully other factors.

I keep my 5Ghz and 2.4Ghz networks with separate SSIDs so I can put different devices in different spaces. I then manually select the 5Ghz channel or the 2.4Ghz channel.

Same here.

I actually removed the 2.4Ghz network from Keychain as @RichardF mentioned to force all my Apple devices to use the 5Ghz network.

 

[jayess]

Assuming you have the same SSID on both, your MacBook is supposed to select the best choice based on various criteria such as signal strength, noise, and hopefully other factors.

I keep my 5Ghz and 2.4Ghz networks with separate SSIDs so I can put different devices in different spaces. I then manually select the 5Ghz channel or the 2.4Ghz channel.

Many thanks for the information. The SSID is, indeed, the same on both and also the same password.