txpower not configurable?

[ILikeFish]

I'm trying to figure out what's going on with txpower on my Almond+, running the latest firmware.

In the UK, AFAICT 5GHz A-lower bands should be able to transmit at 200mW / 23dBm.

However, txpower is reported by iwconfig as 17dBm.  I don't seem to be able to boost this.

Also, is there any plan to support DFS bands?

Thanks
Jon

[SecureComp]

Make sure you have your country/region set correctly. 

Also double check your 20/40/80Mhz setting as that limits the channels that can actually be used during DCS.

[ILikeFish]

Yes, it's set to the UK.  I have 80MHz selected, though adjusting it appears to have no effect on the txpower reported by iwconfig.

Thanks
J

[SecureComp]

Change it to 20Mhz and set the channel to 36-64 but those will top out at 20mW.

Changing to channels 100-140 ups the power.

Really the best thing to do is run with 80Mhz and let the system do it's thing to hunt up bandwidth.  If you have a lot of interference (not seeing the throughput you are hoping for), then drop it to 20/40Mhz.

[SecureComp]

A quick look at my iwconfig. (U.S. specs)
Tx Power at 29 dBm or 800 mW

Running 80MHz, not a lot of interference in the area so it can hunt up the preferred channels with room. My 3x3 channel shows up nicely at 1.3 Gb/s.  Note that my 5gig frequency is 5.745MHz putting me in the 800/1000mW range and the Tx Power is right there where it needs to be. Maybe post up your iwconfig output. (remove encryption and SSID info)

These guys did a nice basic writeup of what is possible in the US and Euro specs.
http://www.quantenna.com/pdf/Intro80211ac.pdf

sensitive info removed

Code: [Select]

wlan00    IEEE 802.11ac  ESSID:"XXXXXX" 
          Mode:Master  Frequency:5.745 GHz  Access Point: XX:XX:XX:XX:XX:XX   
          Bit Rate=1.3 Gb/s   Tx-Power=29 dBm   
          RTS thr:off   Fragment thr:off
          Encryption key:RRRR-DDDD-BBBB-NNNN-YYYY-XXXX-XXXX-XXXX [2]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:795  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

wlan10    IEEE 802.11ng  ESSID:"YYYYY" 
          Mode:Master  Frequency:2.452 GHz  Access Point: XX:XX:XX:XX:XX:XX
          Bit Rate:450 Mb/s   Tx-Power=29 dBm   
          RTS thr:off   Fragment thr:off
          Encryption key:RRRR-DDDD-BBBB-NNNN-YYYY-XXXX-XXXX-XXXX[2]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:2301  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0



[SecureComp]

I should also mention, given the title of this thread, that the power isn't "configurable" and shouldn't be. It is set according to the Standards and Specs of the given Region and Frequency/Bandwidth being used.

That said, without seeing the exact results of your iwconfig, can't help you much more but the US Region/Frequency Specs appear to be implemented correctly.

[ILikeFish]

Thanks for the detailed response 

My iwconfig output:

wlan00    IEEE 802.11ac  ESSID:""
          Mode:Master  Frequency:5.18 GHz  Access Point:
          Bit Rate=1.3 Gb/s   Tx-Power=19 dBm
          RTS thr:off   Fragment thr:off
          Encryption key: [3]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:2354  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

wlan10    IEEE 802.11ng  ESSID:""
          Mode:Master  Frequency:2.462 GHz  Access Point:
          Bit Rate:216.7 Mb/s   Tx-Power=20 dBm
          RTS thr:off   Fragment thr:off
          Encryption key: [3]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:2752  Rx invalid crypt:8201  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

It's currently on channel 36 (there are only 4 channels available, and IIRC 80MHz will cover them all), country is UK and there are zero other 5GHz networks where I am...  Max permissable power is 200mw, which is around 23dBm IIRC.

I'll try changing it to 20MHz and see if that's any different.

J

[summat]

I get the same in the UK - txpower on 5GHz maxes out at 19dBm (~80mw) of the allowed 23dBm (~200mw). No matter what channel width I try.

I'm also wondering if DFS support will ever arrive - allowing us to use the 30dBm (1000mw) channels (100-140).

My 7 year old draft-n spec Airport Extreme handles DFS channels just fine..

[SecureComp]

Thanks for the detailed response 

My iwconfig output:

wlan00    IEEE 802.11ac  ESSID:""
          Mode:Master  Frequency:5.18 GHz  Access Point:
          Bit Rate=1.3 Gb/s   Tx-Power=19 dBm
          RTS thr:off   Fragment thr:off
          Encryption key: [3]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:2354  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

wlan10    IEEE 802.11ng  ESSID:""
          Mode:Master  Frequency:2.462 GHz  Access Point:
          Bit Rate:216.7 Mb/s   Tx-Power=20 dBm
          RTS thr:off   Fragment thr:off
          Encryption key: [3]   Security mode:open
          Power Management:off
          Link Quality=94/94  Signal level=-96 dBm  Noise level=-95 dBm
          Rx invalid nwid:2752  Rx invalid crypt:8201  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

It's currently on channel 36 (there are only 4 channels available, and IIRC 80MHz will cover them all), country is UK and there are zero other 5GHz networks where I am...  Max permissable power is 200mw, which is around 23dBm IIRC.

I'll try changing it to 20MHz and see if that's any different.

J

You need to be on a different channel. The reported frequency only supports 20mW.

UK/Japan/Eur spec iirc

Ch 36-64 20mW
Ch 100-140 1000mW


80 Mhz grabs up 4 20MHz Channels at a time, 5 total available in the U.S., only 4 in the UK / Japan.
You want to be at 5490-5710MHz and you are currently at 5.180MHz

There is a new spec for Europe for 2015 but the Almond+ hardware/radios are a couple years old and I would review the older spec.

New Spec
http://www.cisco.com/c/dam/en/us/solutions/collateral/enterprise-networks/802-11ac-solution/q-and-a-c67-734152.doc/_jcr_content/renditions/q-and-a-c67-734152_9.jpg

[SecureComp]

I get the same in the UK - txpower on 5GHz maxes out at 19dBm (~80mw) of the allowed 23dBm (~200mw). No matter what channel width I try.

There are a number of possible reasons for this including beam forming.

I'm also wondering if DFS support will ever arrive - allowing us to use the 30dBm (1000mw) channels (100-140).

My 7 year old draft-n spec Airport Extreme handles DFS channels just fine..

Pros and Cons of DFS are numerous. Lots of non commercial systems do not implement this due to the requirement to scan for radar and shutdown for 30 mins if found for example.

[SecureComp]

I'm also wondering if DFS support will ever arrive - allowing us to use the 30dBm (1000mw) channels (100-140).

My 7 year old draft-n spec Airport Extreme handles DFS channels just fine..

Just a little more info on DFS and why it's more of challenge to implement.
snipped from http://www.extremenetworks.com/understanding-fccetsi-dfs-regulations-for-802-11ac-deployments

Before getting carried away with the higher data rates available with 802.11ac it is important to understand the regulatory aspects for the 5GHz band. Many of the frequencies in the 5GHz band are also used by radar equipment for first responders, airports, weather stations and military installations.  Because of this there are very stringent government regulatory requirements that must be followed by Wi-Fi radios when operating on these frequencies. The regulatory bodies specifying and enforcing these requirements in North America is the Federal Communications Commission (FCC) and in the European Union it is the European Telecommunications Standards Institutes (ETSI). Requirements/specifications for operating on the 5GHz band are called Dynamic Frequency Selection (DFS).  DFS allows unlicensed devices to use the 5GHz band already allocated to radar systems without causing interference to those systems.

These DFS requirements are complex and costly to get regulatory certification from FCC/ETSI. Following are the typical requirements for access points (AP) operating on 5GHz DFS channel:

Before starting operation on DFS channel, scan the channel for Radar devices for 1 minute. If radar is detected follow step 4 otherwise start operation of DFS channel.

Must detect non-Wi-Fi Radar devices with pulse width as small as 5us

When radar device are detected stop operation on the channel within 500 milliseconds.

For AP vendors, this also means informing wireless clients to move away from this channel.

Do not become operational of this DFS channel for at least 30 minutes and after that go to step 1 before becoming operational again.

Given the above complexity many small office-home office vendors as well as some enterprise AP vendors don’t allow operation on DFS channels in the 5GHz band at all. Many client devices are also not certified for DFS band operation. Even when APs are certified and support DFS channels AP vendors often recommend operation exclusively on non-DFS channels given the uncertainty of DFS channels support at the client device level.

[ILikeFish]

You need to be on a different channel. The reported frequency only supports 20mW.

200mW actually, but yes.  However, 19dBm is just under 80mW.  This is what I don't quite understand, why is it apparently limited to a low tx power?  You mention beamforming in a post above?

UK/Japan/Eur spec iirc

Ch 36-64 20mW
Ch 100-140 1000mW


80 Mhz grabs up 4 20MHz Channels at a time, 5 total available in the U.S., only 4 in the UK / Japan.
You want to be at 5490-5710MHz and you are currently at 5.180MHz

That's kind of the problem - we can't, as those bands in the UK require DFS.  That's why I'm interested in maximizing tx power on the A-lower bands, as those are the only ones that don't need DFS.

Thanks!
Jon

[SecureComp]

200mW actually, but yes.  However, 19dBm is just under 80mW.  This is what I don't quite understand, why is it apparently limited to a low tx power?  You mention beamforming in a post above?

That's kind of the problem - we can't, as those bands in the UK require DFS.  That's why I'm interested in maximizing tx power on the A-lower bands, as those are the only ones that don't need DFS.

Thanks!
Jon

I'll have to do a little digging tomorrow, out of time today. But I do remember that there were changes proposed to the Euro spec because Tx Power was not as good as it could have been because of specs related to aggregated 20MHz channel spectral masks versus considering the 80MHz bandwidth as a single channel and changing the allowances/tolerances.

http://www.ieee802.org/11/email/stds-802-11-reg/msg00354.html

My gut tells me I'm overthinking this a little and the answer is more straightforward, such as what devices are connecting to your network.

Silly question, do you have any 802.11ac capable devices that support 3x3, like a 2013 or later MACBook Pro?

[ILikeFish]

I'll have to do a little digging tomorrow, out of time today. But I do remember that there were changes proposed to the Euro spec because Tx Power was not as good as it could have been because of specs related to aggregated 20MHz channel spectral masks versus considering the 80MHz bandwidth as a single channel and changing the allowances/tolerances.

http://www.ieee802.org/11/email/stds-802-11-reg/msg00354.html

I don't understand a word of that ;-)

My gut tells me I'm overthinking this a little and the answer is more straightforward, such as what devices are connecting to your network.

Silly question, do you have any 802.11ac capable devices that support 3x3, like a 2013 or later MACBook Pro?

I'm typing this on a Late 2013 Macbook Pro (MacBookPro11,3) which definitely supports 802.11ac, not sure about 3x3 though - I'll look it up.

Having said that, I can't get the macbook to stay working on 5GHz with my Almond+ for more than a minute or so - wifi stays connected but no IP packets seem to make it through.  That's probably another question though!

J

[SecureComp]

There are several well known issues with MACBook Pro's and 802.11ac and 802.11h and some workarounds.

I had the links back before the site went down, will have to hunt them up again.