TX-Power limits for ath10k based card on Linux 3.18.24 (long term support)?

Ben Greear greearb at candelatech.com
Tue Nov 17 09:11:31 PST 2015

On 11/17/2015 09:02 AM, Joerg Pommnitz wrote:
> Ben,
> thanks for taking the time to answer. I followed your suggestion and repeated my tests
> with your beta-15 firmware.
> The results are interesting. At first I thought nothing had changed. The txpower was about 10dB,
> far short of the expected 20dB. Playing around with "iw dev ap set txpower fixed ... " did not result in significiant changes.
> However, when I add an attenuator between the powermeter and the antenna, the measured txpower markedly increased. With 10dB attenuation I get 12dB, with 20dB attenuation the txpower increases to more than 15dB.
> Question: Is this the expected behaviour? Can I force a fixed txpower instead of this dynamic adaptation?

I'm not aware of any logic in the firmware that would adjust power automatically
based on attenuation on the antenna connectors.

Any chance the issue is how you are measuring things?

Maybe try the same test with an ath9k NIC and see how it performs?

Do you see similar results with other firmware when you add attenuation?

Are you connecting just to channel 0 on the NIC, or are you connecting to
all three antenna ports?  With 11g, you should only see signal on the
first channel I think.


Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

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