AirOS 3.4 is stealing 4dBm from my PicoStation2!!!!

[MCunha]

Last week I've tested my pico2 with OpenWRT. Today, one week after run the pico2 with OpenWRT, I change back to AirOS 3.4. Right after the firmware change I noticed a signal loss.

Because of this signal loss, I started several tests. Just before give-up and change back to OpenWRT, I saw a very strange report from iwlist: it was reporting 4dBm less then I've set @ AirOS web interface.

Then, I've reset the Pico2 to default settings and, immediately after that, logon by SSH and the power was right, 20dBm @ AirOS and SSH:

http://img195.imageshack.us/img195/5374/20dbmafterressetok.th.jpg (http://img195.imageshack.us/my.php?image=20dbmafterressetok.jpg)

I thought everything was OK, solved by a reset. But, unfortunately, as soon I've change ANYTHING in 'wireless basic' and save the AirOS starts to steal 4dBm again!
When I say anything is really anything: if I reset and change from station to AP, will cheat 4dBm; if I reset then change the country, will steal 4dBm. If I check 'obey regulatory power’ will steal 4dBm; if I uncheck it, will steal...

So, the only moment it will work @ 20dBm is after reset, before the setup.
Since a picture says more than a thousand words, let’s see a few:

http://img197.imageshack.us/img197/3338/20dbmcheating.th.jpg (http://img197.imageshack.us/my.php?image=20dbmcheating.jpg) http://img37.imageshack.us/img37/6325/15dbmcheating.th.jpg (http://img37.imageshack.us/my.php?image=15dbmcheating.jpg) http://img44.imageshack.us/img44/6546/12dbm.th.jpg (http://img44.imageshack.us/i/12dbm.jpg/)

I can force the Pico2 switch back to 20dBm using telnet or SSH by 'iwconfig ath0 txpower 20', but this will keep it at the full power just after the next restart.

Is this a bug or what?

Thanks in advance.

[UBNT-Mike.Ford]

Asking my software team to respond.

Thanks,

Mike

[MCunha]

Thanks Mike!

Just correcting the last part:

I can force the Pico2 switch back to 20dBm using telnet or SSH by 'iwconfig ath0 txpower 20', but this will keep it at the full power until the next restart.

Regards.

[MCunha]

Hi Mike,

Any word from software team about this issue?

This bug is not present in Bullet2 AirOS:

http://img32.imageshack.us/img32/6262/bullet216dbm.th.jpg (http://img32.imageshack.us/i/bullet216dbm.jpg/)

So, I'm starting to think maybe this isn't a bug, but a safety precaution. Do the Pico2 radio can handle with 20dBm without distortion or without risk the device?
If I switch back to OpenWRT, can I set it to 20dBm or respect the 16dBm from AirOS (not the web one, but the real one)?

Regards and thanks in advance.

[MCunha]

Hi,

I did more tests today. I downgraded the unit to version 3.3.2.
The same estrange behavior occurs: the real TX Power is 4dBm less then the power set in AirOS:

http://img246.imageshack.us/img246/5299/pico33216dbbug.th.jpg (http://img246.imageshack.us/my.php?image=pico33216dbbug.jpg)

I suggest to PicoStation owners to verify the REAL power, by login in SSH or telnet, and run the following command to know the real TX Power from the unit:

iwlist ath0 txpower

Looks like this "bug" isn't new... I'm afraid to ask, but, can this "bug" be premeditated? Perhaps the unit can't survive very long @ 20dBm, or generate to much distorted signal?

Regards.

[j7r4]

Chances are it's actually the opposite to what you think. See here: http://www.ubnt.com/forum/viewtopic.php?t=12788

So you will probably find the real power is 4dB greater then what you see via iwlist and the power displayed in AirOs is correct.

[UBNT-Edmundas]

Hi all,

iwconfig command shows tx power set in driver, but real transmit power is calculated with offset. So if you set 20dBm from UI, it will be real device's transmit power.
Forcing higher tx power from shell can damage your radio. Better don't do it. :)

-Edmundas