更改 fonera 無線訊號強度

更改 fonera 無線訊號強度
change the wifi tx-power of the fonera (plus)

Recently I read in the FON-Forums, that some people are using huge antennas with their Foneras. Some of them now seem to be concerned about not meeting legal regulations concerning tx power anymore… Well… even though I personally don’t know anyone who’d really care, you can of course cut down the tx power to a level that suits your needs! So let’s check what’s standard:

root@OpenWrt:~# iwconfig ath0 | grep Tx-Power
Bit Rate:0 kb/s Tx-Power=18 dBm Sensitivity=0/3

As you can see, normal configuration is on 18dBm, which, in my calculations, should result into output power of 63mW. You can backcheck this via console:

root@OpenWrt:~# iwlist ath0 tx
ath0 8 available transmit-powers :
0 dBm (1 mW)
6 dBm (3 mW)
8 dBm (6 mW)
10 dBm (10 mW)
12 dBm (15 mW)
14 dBm (25 mW)
16 dBm (39 mW)
18 dBm (63 mW)
Current Tx-Power:18 dBm (63 mW)

Standard config indeed is 18dB = 63mW. You also get a list of all available power steps for the particular interface, where ath0 would refer the public and ath1 the private one. Now you can set tx power to one of the choices listed above. No need to tell whether you are setting dBm or mW, it will know by the numbers. E.g. for setting ath0 to 16dB = 38mW you would type:

root@OpenWrt:~# iwconfig ath0 txpower 16

And then just check back for success:

root@OpenWrt:~# iwconfig ath0 | grep Tx-Power
Bit Rate:0 kb/s Tx-Power=16 dBm Sensitivity=0/3

Now please don’t misuse this setting to virtually disable the FON concept by cutting down on ath0! :)

http://www.easy2design.de/bla/?page_id=98#txpower