设置无线网卡发射功率——iwconfig wlan0 txpower 30mW - not working

http://askubuntu.com/questions/597546/iwconfig-wlan0-txpower-30mw-not-working

I would like to increase the power of my wireless adapter but when I enter

sudo iwconfig wlan0 txpower 30mW

in the terminal and then check with

iwconfig

I can see that the txpower is still what it used to be before I tried changing it.

My network controller is:

02:00.0 Network controller: Intel Corporation Wireless 7260 (rev 73)

And here is the

ifconfig

output if that helps:

wlan0
Link encap:Ethernet  HWaddr 80:19:34:f5:39:08
inet addr:192.168.1.129  Bcast:192.168.1.255  Mask:255.255.255.0
inet6 addr: fe80::8219:34ff:fef5:3908/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:4474 errors:0 dropped:0 overruns:0 frame:0
TX packets:3726 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:2361924 (2.3 MB)  TX bytes:520175 (520.1 KB)

However, just as a side note,

sudo iwconfig wlan0 power off

is working, for switching

wlan0

's power management off.

Answers

@wie5Ooma, Is right about violating the law. but about the answering the question.
As it goes:

WARNING Removing all restrictions is illegal in the United States.
This is only for educational reasons, and if you choose to
apply it and break the law, then that is your choice and not mine.
Please be careful putting this into action.
This is for Education purpose only!

First we gonna need to use some packages:

python-m2crypto

libgcrypt11

libgcrypt11-dev

libnl-dev

To check if they're installed:

dpkg -s python-m2crypto libgcrypt11 libgcrypt11-dev libnl-dev

If not, to install:

apt-get install python-m2crypto libgcrypt11 libgcrypt11-dev libnl-dev

Now, you'll need wireless regulatory database CRDA, and

wireless-regdb

tools to build the database read by CRDA to provide regulatory domains to the Linux kernel.

CRDA

Wireless-regdb

Navigate to the download folder and unzip the files.

Now here is the interesting part. This is where we actually get to change the regulations. Change your directory to the

wireless-regdb

folder, and in there you will find a file called

db.txt

. This is the file we will edit. Let's take a quick look at it:

more db.txt

Now let's take a look at a few things here. Look at what I underlined above. First, let's notice the first entry (

country 00

)
which is the world regulatory domain and this is applied before all
else. So when you turn on your BackTrack system, the world domain is
applied to you first and then you can change regulatory domains from
there to other countries like country AM.

The second thing I underlined, which can go a max of 20 dBm, the third thing I underlined, on the 2.4ghz band. If you wanna change how high you can go, that is the number you want to change.

For example, let's change Bolivia's rules*

nano db.txt
Scroll down until you find country BO.


Look at what I highlighted. This is the number we want to change.

If your card can go up to 2000 mW, then you would change that number to 33, which stands for 33 dBm, which is approximately 2000 mW. The number you are replacing is in decibels.

I am not sure about your card, some wireless cards like the AWUS036NHA may be stuck in a country and cannot be changed from that country. In
that case, Find out which country your card believes it is in and change
that country's configurations.

Quick DECIBEL understanding:

Every 10 decibels is a 10X increase in power starting from 1 dBm equal
to 1mW... 10 dBm equals 10 mW, 20 dBm equals 100 mW, 30 dBm equals 1000 mW, and so on. Quick DECIBEL understanding:

Every 10 decibels is a 10X increase in power starting from 1 dBm
equal to 1mW... 10 dBm equals 10 mW, 20 dBm equals 100 mW, 30 dBm equals
1000 mW, and so on. Every 3 decibels is approximately double that of
the prior power, so 30 dBm is 1000 mW, if we add 3 dBm, then we can
double the power such that 33 dBm is about equal to 2000 mW.
Every 3 decibels is approximately double that of

the prior power, so 30 dBm is 1000 mW, if we add 3 dBm, then we can
double the power such that 33 dBm is about equal to 2000 mW.

Now, Pay attention.



Notice now I changed the number to 33. When we are finished here, when I change my regulatory domain to BO, i can set my

txpower

to 33.

Now save the changes when you are done by pressing first, Ctrl+X, then Y, and finally, Enter.

Now you need to swap our old regulatory file with the one you downloaded. While still in the

wireless-regdb

directory, just enter the command

make

.

You'll notice you have some new files now in that directory. This is good.
your

regulatory.bin

file in this directory now needs to be replaced with the old one.

First navigate to the authentic

regulatory.db

's location.

cd /usr/lib/crda

And let's also make a backup of the old one just in case (Recommended).

mv regulatory.bin regulatoryOLD.bin

Now let's bring in the new one. Go back to your directory of our new
regulatory.bin and let's copy it over and verify it's there.

cd {path to your new regulatory.bin}
cp regulatory.bin /usr/lib/crda/regulatory.bin
cd /usr/lib/crda
ls

Validating Now we have our new regulatory.db, but it is not valid yet. Go back to
the wireless-regdb directory and you'll notice you have some files with
an extension of .pem. Copy ALL files ending with a

.pem

into your downloaded

crda

directory in

pubkeys

. These are the files that CRDA will use to check if

regulatory.bin

is valid.

cd ~/Desktop/wireless-regdb-2013.10.11
cp root.key.pub.pem ~/Desktop/crda-1.1.3/pubkeys/root.key.pub.pem
cp linville.key.pub.pem
~/Desktop/crda-1.1.3/pubkeys/linville.key.pub.pem

And verify:

cd ~/Desktop/crda-1.1.3/pubkeys
ls

Finally, Now go up a directory from where you are back to the downloaded

crda

directory and install this puppy.

cd ..
make
make install

You should be seeing something like that.


If so, reboot:

sudo reboot

After reboot:

iw reg set BO
iwconfig wlan0 txpower 33