Posted: Thu Mar 26, 2015 12:10 Post subject: Problems setting tx power in WDR3600
Hello everybody,
I have just installed DD-WRT (build 25760) on a TPLINK WDR3600. I have a little problem with wireless settings of the 2.4 GHz device (ath0).
I live in Italy, and maximum transmit power for almost all channels is 20 dBm, as it could be verified by iw:
root@DD-WRT:~# iw phy phy0 info
Wiphy phy0
max # scan SSIDs: 4
max scan IEs length: 2257 bytes
Retry short limit: 7
Retry long limit: 4
Coverage class: 5 (up to 2250m)
Device supports AP-side u-APSD.
Device supports T-DLS.
Available Antennas: TX 0x3 RX 0x3
Configured Antennas: TX 0x3 RX 0x3
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* WDS
* monitor
* P2P-client
* P2P-GO
Band 1:
Capabilities: 0x11ef
RX LDPC
HT20/HT40
SM Power Save disabled
RX HT20 SGI
RX HT40 SGI
TX STBC
RX STBC 1-stream
Max AMSDU length: 3839 bytes
DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 8 usec (0x06)
HT TX/RX MCS rate indexes supported: 0-15
Frequencies:
* 2412 MHz [1] (19.0 dBm)
* 2417 MHz [2] (20.0 dBm)
* 2422 MHz [3] (20.0 dBm)
* 2427 MHz [4] (20.0 dBm)
* 2432 MHz [5] (20.0 dBm)
* 2437 MHz [6] (20.0 dBm)
* 2442 MHz [7] (20.0 dBm)
* 2447 MHz [8] (20.0 dBm)
* 2452 MHz [9] (20.0 dBm)
* 2457 MHz [10] (20.0 dBm)
* 2462 MHz [11] (18.0 dBm)
* 2467 MHz [12] (20.0 dBm)
* 2472 MHz [13] (20.0 dBm)
valid interface combinations:
* #{ managed } <= 2048, #{ AP } <= 8, #{ P2P-client, P2P-GO } <= 1, #{ IBSS } <= 1,
total <= 2048, #channels <= 1, STA/AP BI must match
* #{ WDS } <= 2048,
total <= 2048, #channels <= 1, STA/AP BI must match
HT Capability overrides:
* MCS: ff ff ff ff ff ff ff ff ff ff
* maximum A-MSDU length
* supported channel width
* short GI for 40 MHz
* max A-MPDU length exponent
* min MPDU start spacing
However, even if I set 20 dBm in the TX Power section of Advanced Settings in the web interface, what I always get from wireless status panel is that TX Power is 17 dBM. This is also confirmed by iwconfig:
Code:
root@DD-WRT:~# iwconfig ath0
ath0 IEEE 802.11bgn Mode:Master Tx-Power=17 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:off
Can anybody help me to understand if this is a bug or if I am doing something wrong?
Try Canada or United States instead of Italy and keep the channel manually set. I also get 17 dBm if I set Auto channel and Germany. So now I use Canada, channel 11 (it's not so crowded around it). My WNDR3800 works at 20 dBm without issues. No antenna gain. _________________ THERE ARE NO STRANGERS HERE; ONLY FRIENDS YOU HAVEN'T YET MET.
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Try Canada or United States instead of Italy and keep the channel manually set. I also get 17 dBm if I set Auto channel and Germany. So now I use Canada, channel 11 (it's not so crowded around it). My WNDR3800 works at 20 dBm without issues. No antenna gain.
Ok, now with Canada it is finally working at 20dBm. I assume then this is a bug of wireless implementation, should I report it somewhere?
If the channel is chosen automatically the tx-power might fall down to the lowest allowed (in this case: chipset-available) power, which is 18 dBm. It shouldln't fall down to 17 dBm, especially when using a manual channel where 20 dBm are allowed. So i think, this might be really a bug!
michelasso set:
a fixed allowable channel, like 6
Reg in IT.
Channel Width in HT40
antenna gain to 0.
You must have the max 20dB TX Power w/ this settings. _________________ dd-wrt is addict...
michelasso set:
a fixed allowable channel, like 6
Reg in IT.
Channel Width in HT40
antenna gain to 0.
You must have the max 20dB TX Power w/ this settings.
I am sorry but this does not happen...here's my settings:
As you see in his "iw reg get"- and "iw phy phy0 info"-outputs, italy also allows 20 dBm!
KrypteX wrote:
... and keep the channel manually set.
You already mentioned this!
KrypteX wrote:
My WNDR3800 works ...
He has a WDR3600 (which is TP-Link) and no(!) WNDRxxxx (which is Netgear).
mittelhessen, I know the difference between TP-Link and Netgear models, I'm not blind !
And I know exactly why I said what I said, because this is an old bug in DD-WRT, I even opened a related bug ticket http://svn.dd-wrt.com/ticket/3740 in which I mentioned the 17 dBm only issue and BrainSlayer replied, etc. But still no fix.
That's why I say AGAIN: use Canada or US with channel explicitly set and it will work properly. If you set European countries (Germany, France, Italy etc.) you'll see the bug, especially on the 5G band.
You are all free to reopen/add new info to the ticket. It might get fixed. _________________ THERE ARE NO STRANGERS HERE; ONLY FRIENDS YOU HAVEN'T YET MET.
________________________________________________________________________________________________________
DD-WRT CHANGELOG | DEVICES | DD-WRT BUILDS | KONG BUILDS | UNOFFICIAL BUILDS | DD-WRT in VIRTUALBOX
something going wrong w/ your screenshoots you posted.
In Settings the ACK Timing is 0 meters.
In Status shown as in 2250m.
Maybe you see a status of another router or is the cashe of previous status. Clear your browser cashe.
Also in Mode set the Mixed mode - not NG Mixed.
The build 25760 is old now. Latest is r26490 _________________ dd-wrt is addict...
something going wrong w/ your screenshoots you posted.
In Settings the ACK Timing is 0 meters.
In Status shown as in 2250m.
Maybe you see a status of another router or is the cashe of previous status. Clear your browser cashe.
Also in Mode set the Mixed mode - not NG Mixed.
The build 25760 is old now. Latest is r26490
No, no other router, however I cleared the cache and set the mode to mixed, as you suggested, and nothing has changed.
Moreover, web stats could be influenced by old cache, but the output of iwconfig in terminal doesn't, and it always says Tx-Power=17dBm.
Maybe the ack timing not reported correctly is another bug...
