How to change TX-power in WRT1900ACS?

Changing the Tx-Power does not change the power, I check the power using a smartphone.

Software: OpenWrt 18.06-SNAPSHOT r7405-06a20afb34 / LuCI openwrt-18.06 branch (git-18.329.26825-5e87083)
OpenWrt 17.01

It's not possible to use a cell phone to do what you describe. Did you confirm the power change on the router's command line (e.g. using iw)?

Why can not I check the signal power with a smartphone?
I changed TX-power from 20db to 4db and power signal has not changed.
wlan1 ESSID: ""
Access Point: 62:38:E0:DA:41:F7
Mode: Master Channel: 13 (2.472 GHz)
Tx-Power: 4 dBm Link Quality: 51/70
Signal: -59 dBm Noise: -66 dBm
Bit Rate: 86.6 MBit/s
Encryption: WPA2 PSK (CCMP)
Type: nl80211 HW Mode(s): 802.11bgn
Hardware: 11AB:2A55 11AB:0000 [Marvell 88W8864]
TX power offset: none
Frequency offset: none
Supports VAPs: yes PHY name: phy1

If v2 flavour power table is fixed

cat /sys/kernel/debug/ieee80211/phy0/mwlwifi/info | grep power

cat /sys/kernel/debug/ieee80211/phy0/mwlwifi/info | grep power
power table loaded from dts: no

I guess, it depends on what you actually changed the power to.

Depending... you need this to check a radio's power:

Or RF power meter.

  • Please explain why the system says 4 dBm - as you wish?

The smartphone accurately represents the change in signal strength.

I do not know what to explain here.

  • It says 4 dBm. That's what you wish, correct?
  • Have you reooted?

I'm not sure what you mean here. I'm hoping you don't mean you believe your phone is actually a RF power meter.

I would experiment by walking a distance with the device or laptop at 20 dBm, then changing it to 4 dBm. You may have to do this via command line, so you can definitely observe the disconnect without it revering because the distance is too far for signal at 4dBm.

I set 1,2,3 ... 19, 20 db. Power signal has not changed.
Of course, I did reboot.

Of course, phone is not RF power meter, but a change from 20db to 1db would certainly have noticed

Are you guessing...using web GUI??

Please post /etc/config/wireless

It’s a known fact that the mwlwifi driver doesn’t allow power changing. The command is ignored by the driver.

** this may only apply to the newer devices which load from internal EEPROM rather than DTS power tables. The device mentioned in this thread fits that description anyway.


the file is the same as in the GUI

something can be done about it?

Your complaint/query falls to Linksys/Marvell. The short answer is “no”, the long answer is that it MIGHT be possible if you modify the driver.
BUT, the firmware is closed source, so you’d be doing a bit of guesswork.