[HELP] Transmit power restriction for RT-N66U

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RMerlin

Asuswrt-Merlin dev
I think that the wireless drivers in the router can only accept certain values, and has a number of preset values set. So if you type in 5mW, the driver will set the lowest value it can, which I think is 50mW.

It's one of the reasons it has been requested to have a real GUI for this type of thing, instead of the magical mystery tour numeric input we have now.

One thing I will say, is that it may not be a good idea to run the router without antennas attached. I don't think it would be good for the power amps, but this needs answering by an electrical engineer, or real RF expert.
As long the Broadcom wireless drivers will remain closed-source, you will always have very limited control over whatever happens in that black box I'm afraid.
 

Bagman

Regular Contributor
One thing I will say, is that it may not be a good idea to run the router without antennas attached. I don't think it would be good for the power amps, but this needs answering by an electrical engineer, or real RF expert.
I have had a few routers where the instructions explicitly tell you not to run without antennas attached or you can damage the router, so I try to never run without antennas. Plus if you ever need them, they are much easier to find if they are attached to the router instead of in some drawer or box somewhere.
 

vprasinos

Occasional Visitor
What about having only one or two antennas attached? Does that reduce radiated power or not? What is the real use of all 3 antennas? To cover all planes in a circular pattern as the asus site suggests or another?
 

Stimpy

Occasional Visitor
What about having only one or two antennas attached? Does that reduce radiated power or not? What is the real use of all 3 antennas? To cover all planes in a circular pattern as the asus site suggests or another?
Each antenna has it's own power amplifier, so you should really use all of them connected.

Running with no antennas, or only one or two connected will reduce the amount of radiated power, however the router may well switch from using one of the unconnected radios, to one that has an antenna, due to it detecting a stronger receive signal.

There are tricks involving cardboard covered in tinfoil wrapped around the antenna, which could reduce the power output, but remember that you are also drastically reducing the routers ability to receive a signal...
 

vprasinos

Occasional Visitor
Thanks for the reply. As I see it the best and proper way to reduce the transmit/receive power is to remove all antennas and reduce the output of the router. Is there a way to reduce the power to actually lower than the 50mW?
 

DrTeeth

Senior Member
Also, I noticed that when I remove the antennas the signal reduces a lot. Is it better to reduce the actual signal power or take out the antennas?
ALWAYS the latter. NEVER, ever operate a transmitter without its correct antennas attached.

It is always best practice to reduce the power needed to maintain the connection with as few errors as possible.
 

DrTeeth

Senior Member
For the record, we're talking about the freedom to alter settings in a WiFi router, not murdering or raping. I like to think that I feel differently about those subjects than I do about upping the power in my router. ;)
But you are still being selfish by increasing the power without consideration to your neighbours or anybody else. I just illustrated some other forms of the same behaviour. Your choice how to behave and to take it on the chin if required. Personally, I was brought up differently.
 

Stimpy

Occasional Visitor
But you are still being selfish by increasing the power without consideration to your neighbours or anybody else. I just illustrated some other forms of the same behaviour. Your choice how to behave and to take it on the chin if required. Personally, I was brought up differently.
WTF???

You are personally attacking me just because I get frustrated when I'm told I'm wrong for wanting to use 150mW on my router when the max is 100mW... Yeah, I'm an evil person.

P.S, I don't have any neighbours, just a large house, bought buy evil means... :rolleyes:
 

RMerlin

Asuswrt-Merlin dev
Folks, please try to keep the discussion civilized and on (technical) topic, otherwise I will have to put this thread under lock and key. Thank you :)
 

oversim

Regular Contributor
Hi all. I would like to know if is there a "telnet command" to change current TX wifi power..
So I can set a low output power if there's nobody at home, and wifi is used only for my wifi wather station and other device but not my phone, tablet, etc..
 

oversim

Regular Contributor
Are you sure? I'm not talking about nvram set / get command.. I cannot find what I'm looking for..
Thanks!
 

DrTeeth

Senior Member
Just thought I'd let you guys know that the changes one makes to the radio setting are NOT backed up when backing up settings.

Just got a replacement unit and restored the settings that I backed up last night, and had to enter all the settings again. I did 'nvram commit' when I originally entered the settings.
 

RMerlin

Asuswrt-Merlin dev
Just thought I'd let you guys know that the changes one makes to the radio setting are NOT backed up when backing up settings.

Just got a replacement unit and restored the settings that I backed up last night, and had to enter all the settings again. I did 'nvram commit' when I originally entered the settings.
They do get saved. It's your backup that was corrupted since it was made with a buggy version.
 

oversim

Regular Contributor
Ok, maybe I get it.
I wrote a couples of scripts.

Code:
#!/bin/sh
nvram set wl_TxPower=100
nvram set wl0_TxPower=100
service restart_wireless
and

Code:
#!/bin/sh
nvram set wl_TxPower=10
nvram set wl0_TxPower=10
service restart_wireless
Of course, the first is called "HighPower" and "LowPower" the last one :)

These are for 2.4 band only. wl1_TXPower is the nvram setting for 5Ghz band.
 

ishwest

New Around Here
Composed a simple script to set tx power :)

Code:
#!/bin/sh

# Min and max tx power
MIN_TX=40
MAX_TX=500

usage () {
	echo 'Usage:'
	echo '  set_tx_power.sh [-h] <power>'
	echo
	echo "  Sets WiFi transmit power in mW. Valid values are $MIN_TX through $MAX_TX."
	echo
	echo 'Options:'
	echo '  h - Print usage and exit.'
	echo
} 

if echo $1 | grep -qi '\-h' ; then
	usage
	exit
fi

TX="$1"

if echo $TX | grep -q '^[0-9]\+$' ; then
	if [ "$TX" -lt "$MIN_TX" ] ; then
		echo I refuse to to set tx power below ${MIN_TX} mW
		exit
	elif [ "$TX" -gt "$MAX_TX" ] ; then
		echo I refuse to to set tx power above ${MAX_TX} mW
		exit
	fi
else
	usage
	exit
fi

echo Setting transmit power to ${TX}mW

### SET
nvram set wl_TxPower=$TX
nvram set wl0_TxPower=$TX
nvram set wl1_TxPower=$TX
nvram commit

WE_FAILED=0
 
### CHECK
RES_WL=$(nvram get wl_TxPower)
if [ "$RES_WL" -eq "$TX" ] ; then
	echo "Check: wl set to $TX"
else 
	WE_FAILED=1
	echo "Error: wl is $RES_WL"
fi

RES_WL0=$(nvram get wl0_TxPower)
if [ "$RES_WL0" -eq "$TX" ] ; then
	echo "Check: wl0 set to $TX"
else 
	WE_FAILED=1
	echo "Error: wl0 is $RES_WL0"
fi

RES_WL1=$(nvram get wl1_TxPower)
if [ "$RES_WL1" -eq "$TX" ] ; then
	echo "Check: wl1 set to $TX"
else 
	WE_FAILED=1
	echo "Error: wl1 is $RES_WL1"
fi

if [ "$WE_FAILED" -eq 1 ] ; then 
	echo "Something is broken, now it's up to you to fix it. Bye!"
else
	echo 'Done! You should reboot now!'
fi
Small print: the script comes with no warranty whatsoever, use at your own risk.
 

nurv2600

Occasional Visitor
Awesome! I've got some high(er) gain antennas coming, it will be interesting to see how adjusting this and adding those helps; I'll be sure to adjust up from 80mW with the stock antennas and then again from 80mW with the new ones to see what yields the best results. I realize the whole argument here, and understand that simply turning up the power is not a magical solution; but it is part of it under the right circumstances.

As for this nifty script, I love it, but unfortunately fail to see how it's gonna help anybody that was stumped by the initial telnet->nvram set->nvram commit && reboot in the first place. Nevertheless, it's going in my /opt/ for handy access anyway. Maybe host it somewhere and just tell people to copy-paste "ssh [email protected] "wget -O /opt/txpower.sh ftp://yourfile.com/txpower.sh"" (or "curl" for Mac OS 10.8+ users) I think would do it for most systems. Most people can handle copy-pasting into a terminal.

The number does not represent the real output in mW. In the USA if you sent the 2.4 GHZ tab to 200 mW the real output is 24 dBm or 251 mW. Setting the 5 GHZ professional tab to 200 mW gets you a power output of 20.50 dBm or 141.25 mW
Any validity to this, whether TX power is set via directly calling nvram or the webgui? I find it weird that it would set the power HIGHER than requested on the 2.4 band if set to 200mW max, but either way, I wanna make sure when I set it, I get what I ask for (not vastly more or less).
 

angelsevov

New Around Here
Hello,

- just bought this awesome router

- RT-N66U updated to merlin firmware 3.0.0.4.266.23b

- bought and is using this router in Singapore (APAC)

- default transmit power 80mw

- want to attain max transmit power 500mw

- but max transmit power 200mw:

"Set the capability for transmission power. The maximum value is 200mW and the real transmission power will be dynamically adjusted to meet regional regulations"

- tried to change the timezone of the router, doesn't work.

- doesn't custom firmware bypass all these restrictions? please help!




Update 22 July 2013:

This is just for those who are INTERESTED to test out 500mw transmit power on their RT-N66U, you may enter commands via GUI at 192.168.1.1 > Tools > CMD or via telnet:

### To CHECK your current region, each line entered will result in the answer.
nvram get pci/1/1/ccode
nvram get pci/2/1/ccode
nvram get wl0_country_code
nvram get wl1_country_code
nvram get regulation_domain
nvram get regulation_domain_5G

### To ALTER to a new region such as US(500mw), or GB(200mw), enter or change the last 2 letters accordingly to each line. Its a good idea to CHECK your current region after each command entered.
nvram set pci/1/1/ccode=US
nvram set pci/2/1/ccode=US
nvram set wl0_country_code=US
nvram set wl1_country_code=US
nvram set regulation_domain=US
nvram set regulation_domain_5G=US

### To CHECK your current transmit power, each line entered will result in answer.
nvram get wl_TxPower
nvram get wl0_TxPower
nvram get wl1_TxPower

### To ALTER to a new transmit power such as 500mw(US) or 200mw(GB), enter or change the last 3 digits accordingly to each line. Its a good idea to CHECK your current transmit power after each command entered.
nvram set wl_TxPower=500
nvram set wl0_TxPower=500
nvram set wl1_TxPower=500
nvram commit


After nvram commit command is entered, you may additionally VERIFY values at the GUI > Wireless > Professional > Tx power adjustment. Take note your router temperature MAY rise by about 2 to 3°C and maintain. I have experienced only a 5% average strength increase from 200mw to 500mw. FYI, firmware using is by Merlin 3.0.0.4.372.30_3. Signal strength check using WiFi Explorer 1.5.1.

:)
ok guys i know that this topic is for n66u and i used this codes on my n66u, i'm so grateful.

today i bought an ac68u and some of these commands working some of them not.
RMerlin or someone, do u guys know how can we change ac68u from EU to US? even apple with airport in europe is allowing us to use channel 100 and some other 1xx channels but not ASUS! and i dont wanna use just those 36, 40, 44, 48 :(

i tested just "nvram get" codes to check my current transmit power and to check current region code, im a little bit afraid of "nvram set" command.
these commands are not giving me any answer from router

nvram get pci/1/1/ccode
nvram get pci/2/1/ccode
nvram get regulation_domain
nvram get regulation_domain_5G

and these are working as usual

nvram get wl0_country_code
nvram get wl1_country_code
nvram get wl_TxPower
nvram get wl0_TxPower
nvram get wl1_TxPower

i believe that those works too cause we are geting information from router, so it shouldn't be any problem to set parameter

nvram set wl_TxPower=500
nvram set wl0_TxPower=500
nvram set wl1_TxPower=500
nvram commit

any suggestion?
 

richto

Regular Contributor
just to add, those of us in the UK with the N66U are probably running it on europe settings.

I fixed mine just now using the following.

Code:
nvram set pci/1/1/ccode=GB
nvram set pci/2/1/ccode=GB
nvram set wl0_country_code=GB
nvram set wl1_country_code=GB
nvram set regulation_domain=GB
nvram set regulation_domain_5G=GB
and now have a hell of a lot more 5ghz channels along with 200mw on 5ghz and 2.4ghz

before was 100mw on 2.4
Yes - much better for me in the UK - 5GHz is way improved....I didn't even know there was a GB setting.

If we can't have the ability to control location in the GUI, then perhaps it could at least display the current settings?
 

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