Cannot reduce range when lowering tx power


I have a client station (sta/managed) for which I need to restrict the wireless range. That client use a ubiquiti nanostation m2 (whose integrated antenna is 10 or 11dBi) and runs openwrt 15.05 (custom compiled). That client easily access an AP at 2.5km from it when its tx power is 20dBm.

When I lower tx power to 3dBm (using 'iwconfig wlan0 txpower 3), iwconfig actually shows that 3dBm level but I still can connect to and exchange with that AP at 2.5km far from the client.

Is that normal, or could actually the radio be still using its max power without linux knowing it? How can I check it?

Thank you for your help.

With a extremely clear line of sight (radio-wise) and little other 2.4 GHz inference, yes. That's more common in rural areas

You could lower the Distance Optimization to lower the range.

Try iw dev wlan0 set txpower fixed 300. I had a lot of problems finding a way to set it that actually works, but this seems to. The number is mBm, which is 100 dBm. I don't think all numbers are valid, so try 200 or some other number if it doesn't work.

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