Airport Extreme: Turn off 2,4 GHz wireless network

No, this is not possible.

The AirPort Extreme will always produce both a 2.4 GHz and 5 GHz band. It is not possible to turn one off and leave the other on.

It is possible though, to assign a separate wireless network name to the 5 GHz band....if that is of any interest.

Well, it is possible, but only if you purchase an A1184 AirPort Extreme which is no longer being sold (as you choose 2.4 or 5). Bob Timmons is correct when speaking about the latest Extremes (3rd, 4th and 5th generations).

Good catch. I assumed that andrepeternell had a newer simultaneous dual band AirPort based on his question.....but assuming anything is dangerous.

Did you consider the option to assign a separate name to the 5 GHz network? Or, are you saying that you have a separate name for the 5 GHz network and the iPhone still connects at 2.4 GHz?

If I assign a separate name to the 5 GHz band here, I can "point" my iPhone at that band and it always connects to 5 GHz. You should be able to do this unless the iPhone is having a WiFi issue.

Try Deleting the WiFi settings on the iPhone and then set up a new connection to connect to the 5 GHz name.

If that won't work....you have an iOS issue, not an AirPort Extreme issue.