Opened 8 years ago

Closed 7 years ago

Last modified 4 years ago

#7160 closed defect (wontfix)

madwifi doesn't support Uniquiti XR2 cards full power output

Reported by: Gus Wirth <gwirth79@…> Owned by: nbd
Priority: normal Milestone: Barrier Breaker 14.07
Component: packages Version: Trunk
Keywords: Cc:


I acquired a Soekris net4521 (x86 based board) and installed a Ubiquiti XR2 card. I built two images for it. The first image was OpenWRT trunk r20838 using the provided madwifi (2009-05-08). Testing with that image showed no change from previous test results with other boards (Ubiquiti Router Station) and images. Consider this baseline. An extensive writeup is on the Ubiquiti forum.

The second image was kamikaze_7.09 using the ubnt_hal and the
instructions on the Ubiquiti Wiki "Building_Radio_Driver_for_OpenWrt".

By using the old ubnt_hal I got about 3-4dB improvement over the current OpenWRT trunk. There is still a lot of signal missing but this proves that there are issues with the XR2 card families and the OpenWRT madwifi.

This is a serious problem because the Router Station boards ship with OpenWRT and could be considered defective because they can't run the XR2 cards to full power. Or you could consider the XR2 cards defective, depending on how you want to look at it.

But this is definitely a software issue.

There is an outstanding bug (two years old) listed in the Madwifi TRAC that says the Madwifi driver doesn't work properly for the XR series cards, as measured directly with a power meter, essentially confirming my measurements.

Ticket 2115: new 20080815 hal doesn't correctly set tx power on Ubiquiti XR2

But according to older links (2008) on the OpenWRT forums:

Marek indicates that the stock madwifi driver that comes with OpenWRT should directly support the cards.

Attachments (0)

Change History (6)

comment:1 Changed 8 years ago by anonymous

Just a thought, but have you considered using ath5k instead of madwifi? It may not make a difference though.

comment:2 Changed 8 years ago by thepeople

  • Owner changed from developers to nbd
  • Status changed from new to assigned

comment:3 Changed 8 years ago by Gus Wirth <gwirth79@…>

I've already tried ath5k and it didn't make any difference. My thread on the Ubiquiti forum is at

Ignore the part about the spectrum analyser. There was confusion about what it was reading. To find out what it's really telling you requires knowing the bin width and then summing the power in each bin across the full modulation bandwidth, because the power coming from the card is spread in a wide bandwidth which exceeds the bin size. It falls in the category of "too hard". I'm working on trying to get access to some high-end lab grade equipment which will allow direct power measurements.

As it is, the 3dB difference means that half the output power is missing going from the proprietary ubnt-hal to the Madwifi in OpenWrt. This is directly measurable in both "direct connect" and through the air using another Atheros card as the measuring device.

Now if only I could spell Ubiquiti :)

comment:4 Changed 7 years ago by nbd

  • Resolution set to wontfix
  • Status changed from assigned to closed

comment:5 Changed 6 years ago by ubuntroid

does Ubiquiti change the chipset such that the binary HAL could no longer communicate with XR2?

comment:6 Changed 4 years ago by jow

  • Milestone changed from Attitude Adjustment 12.09 to Barrier Breaker 14.07

Milestone Attitude Adjustment 12.09 deleted

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