Hey Guys,

I am deploying multiple routers throughout my home and want to reduce the txpower but don't seem to be able to do so.

What I found:
I set txpower to 1 in /etc/config/wireless, iw wlan* info reports the setting in wireless config file but the actual power output is observed to stay the same regardless of the setting. (-40 dBm for 5ghz, and -36 dBm for 2.4ghz)

It's only when I switch 5ghz channel 149 to channel 36 then I observe a reduction of received signal for 5ghz from -40dBm to -49dBm. This seems to correspond to the regulatory limit

    (2402 - 2472 @ 40), (N/A, 30), (N/A)
    (5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
    (5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
    (5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
    (5735 - 5835 @ 80), (N/A, 30), (N/A)

i.e. high channel (149 in my case) max power limited to 30, while low channel (36) limited to 23.

How do I properly reduce the txpower?

I see listed:

• br-lan - This is by default a combination of wlan0 and wlan1 and eth0.1

• wlan0 - Correct, 5GHz WiFi

• teql0 -virtual interface for load sharing, not used, just ignore it

• eth0 - your main LAN connection, but you don't want to use this, use eth0.1

• wlan1 - Correct, 2.4 GHz Wifi

• bond0 - virtual interface for bonding/aggregation of two interfaces, unused unless you do crazy config, ignore it

• eth1.2 - by default this is your WAN connection (WAN port on back of router) unless you change options in Switch

• ifb1 - virtual device for traffic control, possibly used for SQM (not positive), see ifb0 below, you can ignore

• eth0.1 - by default this is your LAN connection (LAN ports 1 thru 4 on back of router) unless you change options in Switch

• pppoe-wan - virtual interface due to having to login for your fiber connection as you said

• ifb0 - virtual interface if you use QoS, ifb1 is possibly used for SQM (different and better QoS implementation), you can ignore

. I did notice that my computer, which is connect directly to the router via an Ethernet cable, listed the DNS server as 192.168.1.14, even though the router's address is 192.168.1.1, but I'm not sure how to get the router to give out the proper address. Does anyone have any idea how to fix this?

.

Filled in info above.

Basically the only ones you should ever worry about are br-lan, wlan0, wlan1, eth0.1, eth1.2, and in your case possibly pppoe-wan.  If you go changing switch settings, that's when the difference between eth0 and eth0.1 becomes apparent (eth0 is the internal link from the internal switch to the CPU, by default eth0.1 is the external connection of LAN ports 1 thru 4 to the internal switch).

Also, some info here, but not really that much:

Hey Guys,

I am deploying multiple routers throughout my home and want to reduce the txpower but don't seem to be able to do so.

What I found:
I set txpower to 1 in /etc/config/wireless, iw wlan* info reports the setting in wireless config file but the actual power output is observed to stay the same regardless of the setting. (-40 dBm for 5ghz, and -36 dBm for 2.4ghz)

It's only when I switch 5ghz channel 149 to channel 36 then I observe a reduction of received signal for 5ghz from -40dBm to -49dBm. This seems to correspond to the regulatory limit

    (2402 - 2472 @ 40), (N/A, 30), (N/A)
    (5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
    (5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
    (5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
    (5735 - 5835 @ 80), (N/A, 30), (N/A)

i.e. high channel (149 in my case) max power limited to 30, while low channel (36) limited to 23.

How do I properly reduce the txpower?

kyzhk wrote:

Hey Guys,

I am deploying multiple routers throughout my home and want to reduce the txpower but don't seem to be able to do so.

What I found:
I set txpower to 1 in /etc/config/wireless, iw wlan* info reports the setting in wireless config file but the actual power output is observed to stay the same regardless of the setting. (-40 dBm for 5ghz, and -36 dBm for 2.4ghz)

It's only when I switch 5ghz channel 149 to channel 36 then I observe a reduction of received signal for 5ghz from -40dBm to -49dBm. This seems to correspond to the regulatory limit

    (2402 - 2472 @ 40), (N/A, 30), (N/A)
    (5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
    (5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
    (5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
    (5735 - 5835 @ 80), (N/A, 30), (N/A)

i.e. high channel (149 in my case) max power limited to 30, while low channel (36) limited to 23.

How do I properly reduce the txpower?

If the 3200ACM or 1900acs V2 are owned, power is not adjustable. 

Which unit do you own? If it isn't one of these, then it may be a new issue because it seems everyone is always trying to increase power...

Ok. back on LEDE r4651 without the driver patch. Did the DNS on the WAN interface, not intuitive obvious to us neophytes. Working, but tooooooo early to know it this addresses my browser DNS lookup issue. Guessing it will.
Will update IF I still have failures, in other words no news is good news.

I have a wrt1900ac v1. iw wlan* info returns following:

root@WRT1900ACv1:~# iw wlan0 info
Interface wlan0
        ifindex 44
        wdev 0x5
        addr b4:75:0e:ff:f8:6f
        ssid Tomato24_11
        type AP
        wiphy 0
        channel 11 (2462 MHz), width: 20 MHz, center1: 2462 MHz
        txpower 1.00 dBm
root@WRT1900ACv1:~# iw wlan1 info
Interface wlan1
        ifindex 43
        wdev 0x100000008
        addr b4:75:0e:ff:f8:70
        ssid LEDE-WRT1900ac
        type AP
        wiphy 1
        channel 36 (5180 MHz), width: 20 MHz, center1: 5180 MHz
        txpower 1.00 dBm
root@WRT1900ACv1:~#

Changing txpower option in wireless config, and restarting the wifi radios does indeed change the reported tx power. But the received signal strength from my phone has no change.

The only way I was able to significantly change the received signal strength on my phone (5ghz channel 149 -> 5ghz channel 36 drops from -40dBm to -49dBm) is by changing the channel from 149 to 36 which has different upper txpower limit.

kyzhk wrote:

Hey Guys,

I am deploying multiple routers throughout my home and want to reduce the txpower but don't seem to be able to do so.

What I found:
I set txpower to 1 in /etc/config/wireless, iw wlan* info reports the setting in wireless config file but the actual power output is observed to stay the same regardless of the setting. (-40 dBm for 5ghz, and -36 dBm for 2.4ghz)

It's only when I switch 5ghz channel 149 to channel 36 then I observe a reduction of received signal for 5ghz from -40dBm to -49dBm. This seems to correspond to the regulatory limit

    (2402 - 2472 @ 40), (N/A, 30), (N/A)
    (5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
    (5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
    (5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
    (5735 - 5835 @ 80), (N/A, 30), (N/A)

i.e. high channel (149 in my case) max power limited to 30, while low channel (36) limited to 23.

How do I properly reduce the txpower?

You are confusing two things.  The transmit power you can adjust (unless you have a 1900ACS V2, 1200AC V2, or 3200ACM as @david noted).  However, the values you stated, for example "-40 dBm for 5ghz, and -36 dBm for 2.4ghz" that the router is reporting are not transmit power -- those are receive power. 

To measure transmit power, the easiest way is with an app on your smartphone to see if it is actually changing.  And if you don't have any of the 3 above models, you should be able to set it from 1 to 23 dBm, up to 30 dBm depending on the channel.

To change transmit power, you can do so in LuCi or by editing /etc/config/wireless.  You can set radio0 to have a different tx power than radio1.  However, if you have a 1200AC V2, 1900ACS V2, or 3200ACM, changing the setting for tx power will have no effect.  It will stay at the default, either 23dBm or 30dBm.

kyzhk wrote:

I have a wrt1900ac v1. iw wlan* info returns following:

root@WRT1900ACv1:~# iw wlan0 info
Interface wlan0
        ifindex 44
        wdev 0x5
        addr b4:75:0e:ff:f8:6f
        ssid Tomato24_11
        type AP
        wiphy 0
        channel 11 (2462 MHz), width: 20 MHz, center1: 2462 MHz
        txpower 1.00 dBm
root@WRT1900ACv1:~# iw wlan1 info
Interface wlan1
        ifindex 43
        wdev 0x100000008
        addr b4:75:0e:ff:f8:70
        ssid LEDE-WRT1900ac
        type AP
        wiphy 1
        channel 36 (5180 MHz), width: 20 MHz, center1: 5180 MHz
        txpower 1.00 dBm
root@WRT1900ACv1:~#

Changing txpower option in wireless config, and restarting the wifi radios does indeed change the reported tx power. But the received signal strength from my phone has no change.

The only way I was able to significantly change the received signal strength on my phone (5ghz channel 149 -> 5ghz channel 36 drops from -40dBm to -49dBm) is by changing the channel from 149 to 36 which has different upper txpower limit.

Again, you are still confusing transmitted power (from your router) and received power (from your phone).  Use an app on your phone to measure transmit power.  With it at 1dBm, I'm surprised if you have WiFi working outside of the room the router is in.

We have the same understanding. My original post still stand but let me clarify your confusion on the following points:

1) Yes, I did adjust txpower in /etc/config/wireless and restarted radios as stated.
2) After all, a significant change in txpower should lead to a significant change in received power (on my phone). Changing the txpower in /etc/config/wireless from 1 to 20 has zero effect on the received signal strength on my phone.

I did mention the received signal strength at my phone went down from -40 dBm to -49 dBm only by switching the channel from 149 to 36, which has different regulatory upper transmission limit (30 dBm to 23 dBm).

kyzhk wrote:

We have the same understanding. My original post still stand but let me clarify your confusion on the following points:

1) Yes, I did adjust txpower in /etc/config/wireless and restarted radios as stated.
2) After all, a significant change in txpower should lead to a significant change in received power (on my phone). Changing the txpower in /etc/config/wireless from 1 to 20 has zero effect on the received signal strength on my phone.

I did mention the received signal strength at my phone went down from -40 dBm to -49 dBm only by switching the channel from 149 to 36, which has different regulatory upper transmission limit (30 dBm to 23 dBm).

The router cannot measure the received signal strength from your router to your phone.  It is physically impossible.  All it can measure is the received signal strength FROM your phone.  Which won't change no matter how much you change the router's Transmit power.

kyzhk wrote:

Let me clarify your confusion:

wrt1900ac txpower, wrt1900ac 5ghz channel, phone received signal strength
1, 149, -40 dBm
20, 149, -40 dBm
1, 36, -49 dBm
20, 36, -49 dBm

wrt1900ac txpower is the option txpower. With each change the radio is restarted.

Hope this is clear enough, thank you.

As you just said, and I have bolded it above for you, you are looking at signal strength FROM the phone.  Not TO the phone.  Download a simple wifi monitor app on your phone and measure it like that.  It is the only way.

starcms wrote:

kyzhk wrote:

Let me clarify your confusion:

wrt1900ac txpower, wrt1900ac 5ghz channel, phone received signal strength
1, 149, -40 dBm
20, 149, -40 dBm
1, 36, -49 dBm
20, 36, -49 dBm

wrt1900ac txpower is the option txpower. With each change the radio is restarted.

Hope this is clear enough, thank you.

As you just said, and I have bolded it above for you, you are looking at signal strength FROM the phone.  Not TO the phone.  Download a simple wifi monitor app on your phone and measure it like that.  It is the only way.

(The quoted -40 dBm, -49 dBm were average reading from my phone)

kyzhk wrote:

Hey Guys,

I am deploying multiple routers throughout my home and want to reduce the txpower but don't seem to be able to do so.

What I found:
I set txpower to 1 in /etc/config/wireless, iw wlan* info reports the setting in wireless config file but the actual power output is observed to stay the same regardless of the setting. (-40 dBm for 5ghz, and -36 dBm for 2.4ghz)

It's only when I switch 5ghz channel 149 to channel 36 then I observe a reduction of received signal for 5ghz from -40dBm to -49dBm. This seems to correspond to the regulatory limit

    (2402 - 2472 @ 40), (N/A, 30), (N/A)
    (5170 - 5250 @ 80), (N/A, 23), (N/A), AUTO-BW
    (5250 - 5330 @ 80), (N/A, 23), (0 ms), DFS, AUTO-BW
    (5490 - 5730 @ 160), (N/A, 23), (0 ms), DFS
    (5735 - 5835 @ 80), (N/A, 30), (N/A)

i.e. high channel (149 in my case) max power limited to 30, while low channel (36) limited to 23.

How do I properly reduce the txpower?

If the 3200ACM or 1900acs V2 are owned, power is not adjustable. 

Which unit do you own? If it isn't one of these, then it may be a new issue because it seems everyone is always trying to increase power...

3) If each router serve a much small physical volume, the total aggregated capacity can be significantly increased. I think of a unit sphere, with some txpower setting the signal fill the entire unit sphere. If I instead reduce the txpower, I would then be able to partition the unit sphere into lots more smaller sphere, and they each won't interfere with one another even on the same channel. Thus increasing the total capacity.

Thats why I always like to tune txpower way down, and deploy more AP instead of using one AP. But at the end I still put one powerful wired only router facing modem with sqm enabled

Something you did, I have no idea what, is causing your DNS server to be broadcast as 192.168.1.14.  That is your problem.  Never seen or heard of it before.  Don't mean to sound harsh, but it's definitely user error. Just go to System --> Backup/Flash Config and click on Perform Reset.  You'll lose all your settings, but this should fix it.  You might also have to (if you are using windows) load an admin command prompt and issue the commands

or simply unplug the ethernet cable after doing the full reset and while the router is rebooting, power off the pc, boot back up, and then plug the ethernet cable back in.

starcms wrote:

Something you did, I have no idea what, is causing your DNS server to be broadcast as 192.168.1.14.  That is your problem.  Never seen or heard of it before.  Don't mean to sound harsh, but it's definitely user error. Just go to System --> Backup/Flash Config and click on Perform Reset.  You'll lose all your settings, but this should fix it.  You might also have to (if you are using windows) load an admin command prompt and issue the commands

or simply unplug the ethernet cable after doing the full reset and while the router is rebooting, power off the pc, boot back up, and then plug the ethernet cable back in.

I appreciate the reply. However, I have tried performing a reset and re-flashing the factory image from the Linksys firmware. I did not save any settings. As soon as I boot into the fresh OpenWRT install, I experience the problem. No settings have been changed on my part.

I also tried releasing and renewing the network interface on my desktop, but it still picks up the wrong address for the DNS server. Any other suggestions?

kyzhk wrote:

starcms wrote:

As you just said, and I have bolded it above for you, you are looking at signal strength FROM the phone.  Not TO the phone.  Download a simple wifi monitor app on your phone and measure it like that.  It is the only way.

(The quoted -40 dBm, -49 dBm were average reading from my phone)

Ok, assuming you are measuring the signal strength AT the phone FROM the router, since you have a WRT1900AC V1, you should definitely be able to change it.  However, it probably isn't accepting 1dBm as a valid entry.  Try 10 dBm vs 20 and see what you get.

Edit: I believe 4 dBm is the lowest it will accept as valid.  The driver is most likely just ignoring 1 dBm and using the default of 23 or 30 dBm depending on channel.

starcms wrote:

Something you did, I have no idea what, is causing your DNS server to be broadcast as 192.168.1.14.  That is your problem.  Never seen or heard of it before.  Don't mean to sound harsh, but it's definitely user error. Just go to System --> Backup/Flash Config and click on Perform Reset.  You'll lose all your settings, but this should fix it.  You might also have to (if you are using windows) load an admin command prompt and issue the commands

or simply unplug the ethernet cable after doing the full reset and while the router is rebooting, power off the pc, boot back up, and then plug the ethernet cable back in.

I appreciate the reply. However, I have tried performing a reset and re-flashing the factory image from the Linksys firmware. I did not save any settings. As soon as I boot into the fresh OpenWRT install, I experience the problem. No settings have been changed on my part.

I also tried releasing and renewing the network interface on my desktop, but it still picks up the wrong address for the DNS server. Any other suggestions?

I too have definitely experienced the failure to load pages using mostly stock config, r4576 4.4, wrt1900ac v1.