ignored txpower offset on Ubiquiti NanoStation M2

[T-X]

It seems that the 12 dBi antenna of the Ubiquiti NanoStation M2 is properly set in the firmware, at least a 12dB txpower offset is noted in iwinfo. However, the txpower is not reduced accordingly:

$ iwinfo
wlan0     ESSID: "luebeck.freifunk.net"
          Access Point: 24:A4:3C:AC:F4:AC
          Mode: Master  Channel: 1 (2.412 GHz)
          Tx-Power: 30 dBm  Link Quality: 40/70
          Signal: -70 dBm  Noise: -89 dBm
          Bit Rate: 43.6 MBit/s
          Encryption: none
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: 168C:002A 0777:E012 [Ubiquiti NanoStation M2]
          TX power offset: 12 dB
          Frequency offset: none
          Supports VAPs: yes

wlan0-1   ESSID: "02:d1:11:37:fc:38"
          Access Point: 02:D1:11:37:FC:38
          Mode: Ad-Hoc  Channel: 1 (2.412 GHz)
          Tx-Power: 30 dBm  Link Quality: 69/70
          Signal: -41 dBm  Noise: -89 dBm
          Bit Rate: 102.3 MBit/s
          Encryption: unknown
          Type: nl80211  HW Mode(s): 802.11bgn
          Hardware: 168C:002A 0777:E012 [Ubiquiti NanoStation M2]
          TX power offset: 12 dB
          Frequency offset: none
          Supports VAPs: yes

The "Tx-Power" field seems to include the tx power offset (https://dev.openwrt.org/browser/branches/attitude_adjustment/package/iwinfo/src/iwinfo_cli.c?rev=36121#L433). However it should say "Tx-Power: 20 dBm".

The reg domain is set correctly, too:

$ iw reg get
country DE:
        (2400 - 2483 @ 40), (N/A, 20)
        (5150 - 5250 @ 80), (N/A, 20), NO-OUTDOOR
        (5250 - 5350 @ 80), (N/A, 20), NO-OUTDOOR, DFS
        (5470 - 5725 @ 80), (N/A, 27), DFS
        (57240 - 65880 @ 2160), (N/A, 40), NO-OUTDOOR

$ iwinfo wlan0-1 txpowerlist
  12 dBm (  15 mW)
  13 dBm (  19 mW)
  14 dBm (  25 mW)
  15 dBm (  31 mW)
  16 dBm (  39 mW)
  17 dBm (  50 mW)
  18 dBm (  63 mW)
  19 dBm (  79 mW)
  20 dBm ( 100 mW)
  21 dBm ( 125 mW)
  22 dBm ( 158 mW)
  23 dBm ( 199 mW)
  24 dBm ( 251 mW)
  25 dBm ( 316 mW)
  26 dBm ( 398 mW)
  27 dBm ( 501 mW)
  28 dBm ( 630 mW)
  29 dBm ( 794 mW)
* 30 dBm (1000 mW)

[ohrensessel]

Is there a fix for this bug on the horizon? Or is this an openwrt issue?

[lost-tty]

All OpenWRT builds for Ubiquiti devices are affected so it would be best to fix it upstream.

[ohrensessel]

is there an openwrt bug report already or should we create one?

[T-X]

Sorry, had forgotten to forward it to OpenWRT, here it is now: https://dev.openwrt.org/ticket/16744

[corny]

This problem does also appear on my Ubiquiti PicoStation M2. Probably more Ubiquiti devices are affected.

[lost-tty]

Upstream has changed the issue to "wontfix" a few days ago. Any suggestions on what do to next?

[ohrensessel]

bekommen wir das nicht gelöst, in dem wir $irgendwie für die betroffenen geräte die sendeleistung manuell festlegen, ohne uns auf upstream zu verlassen?

ähnlich zu https://github.com/freifunk-gluon/gluon/wiki/Commandline-administration#sendeleistung-auf-nanostation-m2

[lost-tty]

Wenn wir das tun, können wir den Patch auch gleich Upstream einreichen. Im Endeffekt läuft es ja wirklich nur auf eine Liste mit den Verstärkungsfaktoren der Geräte hinaus.