[OpenWrt-Devel] [OpenWrt] 2.4Ghz limited to 50mW in DFS-ETSI
Gerald Matzka
mgerald21 at yahoo.de
Thu Jul 30 12:08:52 EDT 2015
Ben is right, take a look at
https://forum.openwrt.org/viewtopic.php?id=42197
In newer Openwrt versions the kernel modules are compiled to respect the reg-domain settings programmed in hardware.
Kind regards
... sent from my iPhone
> Am 30.07.2015 um 17:11 schrieb Ben West <ben at gowasabi.net>:
>
> You can look up your respective country's spectrum regulations. It is possible prior versions OpenWRT didn't fully conform to each regulatory domain and were fixed in more recent versions (just as the converse is possible).
>
> For example, for the USA, here is a table of power limits for the 2.4GHz and 5GHz bands. Channels 36-48 are limited to 16dBm transmitter power.
> http://www.air802.com/fcc-rules-and-regulations.html
>
>> On Thu, Jul 30, 2015 at 3:32 AM, Nicola von Thadden <nico at vthadden.de> wrote:
>> Hi,
>>
>> I also thought to have used 20dBm or 23dBm in earlier releases (AA).
>> Is there a way to find out to which txpower levels the 5Ghz transceiver
>> is limited? I think the driver reads them out, maybe there is a way to
>> print them on the cmd?
>>
>> But my main problem is the 17dBm on 2.4Ghz when setting DFS-ETSI
>> countries. I don't think that it is a problem of the hardware but of the
>> software parsing the regdom. Maybe there is a fixed limit of 17dBm on
>> non-DFS channels, even when DFS is not required, which is not very
>> useful. Does anyone have an idea where that could be set? My search in
>> the source code had no results until now, where it could be.
>>
>> Thanks
>> Nico
>>
>> On 07/29/2015 06:21 PM, Atanas Vladimirov wrote:
>> > https://dev.openwrt.org/ticket/20201
>> >
>> > On BB I used 20dBm for both 2.4 and 5GHz on the same router.
>> >
>> > Sent with AquaMail for Android
>> > http://www.aqua-mail.com
>> >
>> > On 29 юли 2015 г. 18:40:10 Ben West <ben at gowasabi.net> wrote:
>> >
>> >> This is what I observe running Barrier Breaker on UBNT M5 products,
>> >> too. I believe the 17dBm limit is intentional, i.e. per regulation.
>> >> The 30dBm tx power limit applies to channels 149 and above, I believe.
>> >>
>> >> > Also (kind of off-topic): Do you know why 5Ghz channels 36-48 are
>> >> forced
>> >> > to be 17dBm only on the WNDR3800? I found two possible explanations:
>> >> > either because of the factory calibration
>> >>
>> >>
>> >> On Wed, Jul 29, 2015 at 10:25 AM, Gerald Matzka <mgerald21 at yahoo.de
>> >> <mailto:mgerald21 at yahoo.de>> wrote:
>> >>
>> >> Well, it looks like the txpower of your wdnr3800 is limited to
>> >> 17dBm because of the hardware reg-domain settings.
>> >>
>> >> Kind regards,
>> >>
>> >> ... sent from my iPhone
>> >>
>> >> > Am 29.07.2015 um 10:43 schrieb Nicola von Thadden
>> >> <nico at vthadden.de <mailto:nico at vthadden.de>>:
>> >> >
>> >> > Hi,
>> >> >
>> >> > I have this strange behaviour down below, for which I also opened a
>> >> > ticket because I think this should not be like that ;)
>> >> >
>> >> > Does anyone have an idea where the problem could originate from
>> >> and how
>> >> > to fix it?
>> >> >
>> >> > Thanks
>> >> > Nico
>> >> >
>> >> >> On 07/29/2015 12:37 AM, OpenWrt wrote:
>> >> >> #20222: 2.4Ghz limited to 50mW in DFS-ETSI
>> >> >> ----------------------+----------------------------------
>> >> >> Reporter: nicoduck | Owner: developers
>> >> >> Type: defect | Status: new
>> >> >> Priority: normal | Milestone: Chaos Calmer (trunk)
>> >> >> Component: kernel | Version: Trunk
>> >> >> Keywords: wndr3800 |
>> >> >> ----------------------+----------------------------------
>> >> >> I have got a Netgear WNDR 3800 running with openwrt since quite
>> >> a while.
>> >> >> I now upgraded to the latest version (trunk) and wanted to use
>> >> WLAN within
>> >> >> the regulations here in Germany but also wanted to max out the
>> >> output
>> >> >> power (within the regulations).
>> >> >> Switching the country to Germany limits the maximum output
>> >> power to 17dBm,
>> >> >> although it does show as being limited on 20dBm:
>> >> >> root at OpenWrt:/# iwinfo wlan0 txpower
>> >> >> 0 dBm ( 1 mW)
>> >> >> 1 dBm ( 1 mW)
>> >> >> 2 dBm ( 1 mW)
>> >> >> 3 dBm ( 1 mW)
>> >> >> 4 dBm ( 2 mW)
>> >> >> 5 dBm ( 3 mW)
>> >> >> 6 dBm ( 3 mW)
>> >> >> 7 dBm ( 5 mW)
>> >> >> 8 dBm ( 6 mW)
>> >> >> 9 dBm ( 7 mW)
>> >> >> 10 dBm ( 10 mW)
>> >> >> 11 dBm ( 12 mW)
>> >> >> 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)
>> >> >>
>> >> >> What I did: reset the device, flash it with various builts from
>> >> trunk and
>> >> >> try to figure out what was going on.
>> >> >> I now modified my regdb and was able to isolate the source of
>> >> the problem:
>> >> >> country DE: DFS-ETSI
>> >> >> # entries 279004 and 280006
>> >> >> (2400 - 2483.5 @ 40), (100 mW)
>> >> >> # entry 303005
>> >> >> (5150 - 5250 @ 80), (200 mW), NO-OUTDOOR, AUTO-BW
>> >> >> # entries 304002 and 305002
>> >> >> (5250 - 5350 @ 80), (100 mW), NO-OUTDOOR, DFS, AUTO-BW
>> >> >> # entries 308002, 309001 and 310003
>> >> >> (5470 - 5725 @ 160), (500 mW), DFS
>> >> >> # 60 gHz band channels 1-4, ref: Etsi En 302 567
>> >> >> (57000 - 66000 @ 2160), (40)
>> >> >> Thas does not work and has the mentioned behaviour, 2.4Ghz is
>> >> limited at
>> >> >> 17dBm. It also does not depend on which values are set in the
>> >> regulatory
>> >> >> database for the 2.4Ghz channels, anything over 17dBm will be
>> >> limited to
>> >> >> 17dBm.
>> >> >> running "iw phy phy0 set txpower fixed 2000" gives no error but
>> >> does not
>> >> >> change it to 20dBm. Changing the value to anything below 17dBm
>> >> works
>> >> >> though.
>> >> >>
>> >> >> country DE: DFS-FCC
>> >> >> # entries 279004 and 280006
>> >> >> (2400 - 2483.5 @ 40), (100 mW)
>> >> >> # entry 303005
>> >> >> (5150 - 5250 @ 80), (200 mW), NO-OUTDOOR, AUTO-BW
>> >> >> # entries 304002 and 305002
>> >> >> (5250 - 5350 @ 80), (100 mW), NO-OUTDOOR, DFS, AUTO-BW
>> >> >> # entries 308002, 309001 and 310003
>> >> >> (5470 - 5725 @ 160), (500 mW), DFS
>> >> >> # 60 gHz band channels 1-4, ref: Etsi En 302 567
>> >> >> (57000 - 66000 @ 2160), (40)
>> >> >>
>> >> >> Thad does work. The only change to the entry above is "DFS-FCC"
>> >> instead of
>> >> >> "DFS-ETSI". I can now select any powerlevel between 1 and 20dBm
>> >> and it is
>> >> >> also reported as being used:
>> >> >> root at OpenWrt:/# iwinfo wlan0 txpower
>> >> >> 0 dBm ( 1 mW)
>> >> >> 1 dBm ( 1 mW)
>> >> >> 2 dBm ( 1 mW)
>> >> >> 3 dBm ( 1 mW)
>> >> >> 4 dBm ( 2 mW)
>> >> >> 5 dBm ( 3 mW)
>> >> >> 6 dBm ( 3 mW)
>> >> >> 7 dBm ( 5 mW)
>> >> >> 8 dBm ( 6 mW)
>> >> >> 9 dBm ( 7 mW)
>> >> >> 10 dBm ( 10 mW)
>> >> >> 11 dBm ( 12 mW)
>> >> >> 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)
>> >> >>
>> >> >>
>> >> >> I have no idea why but there seems to be a bug in the code
>> >> parsing the DFS
>> >> >> regulations, limiting 2.4Ghz to lot lower values than allowed.
>> >> Changing it
>> >> >> to DFS-FCC works for using the applicaple output power but does
>> >> not seem
>> >> >> to be in compliance which German law.
>> >> >>
>> >> >> Do you have an idea where the problem could be? I'm happy to
>> >> try out more
>> >> >> builds and future versions.
>> >> >>
>> >> >> Also (kind of off-topic): Do you know why 5Ghz channels 36-48
>> >> are forced
>> >> >> to be 17dBm only on the WNDR3800? I found two possible
>> >> explanations:
>> >> >> either because of the factory calibration (is it possible to
>> >> get them in a
>> >> >> human readable form somehow? The hexdump is not really readable
>> >> and I have
>> >> >> not been able to find the code which pases them) or because
>> >> these channels
>> >> >> are considered as "edge-channels" and someone thought it would
>> >> be safe to
>> >> >> limit the power, to not disturb any other systems running on
>> >> even lower
>> >> >> channels. The latter explanation is kind of weird because it
>> >> would make no
>> >> >> sense to limit these 4 channels but no other ones. I find it
>> >> especially
>> >> >> strange because that is typically the job of regulatory
>> >> authorities, to
>> >> >> define those power levels.
>> >> >>
>> >> >> --
>> >> >> Ticket URL: <https://dev.openwrt.org/ticket/20222>
>> >> >> OpenWrt <http://openwrt.org>
>> >> >> Opensource Wireless Router Technology
>> >> > _______________________________________________
>> >> > openwrt-devel mailing list
>> >> > openwrt-devel at lists.openwrt.org
>> >> <mailto:openwrt-devel at lists.openwrt.org>
>> >> > https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>> >> _______________________________________________
>> >> openwrt-devel mailing list
>> >> openwrt-devel at lists.openwrt.org
>> >> <mailto:openwrt-devel at lists.openwrt.org>
>> >> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>> >>
>> >>
>> >>
>> >>
>> >> --
>> >> Ben West
>> >> http://gowasabi.net
>> >> ben at gowasabi.net <mailto:ben at gowasabi.net>
>> >> 314-246-9434
>> >> _______________________________________________
>> >> openwrt-devel mailing list
>> >> openwrt-devel at lists.openwrt.org <mailto:openwrt-devel%40lists.openwrt.org>
>> >> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>> >>
>> >
>> >
>> > _______________________________________________
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>> >
>
>
>
> --
> Ben West
> http://gowasabi.net
> ben at gowasabi.net
> 314-246-9434
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