Transmit power on E4200

Discussion in 'Tomato Firmware' started by ithrowpicks, Feb 11, 2012.

  1. ithrowpicks

    ithrowpicks Networkin' Nut Member

    I noticed changing the transmit power would not result in a signal change in inSSIDer so I tried the following based on info taken from the FAQ's Toastman maintains and the NVRAM settings and it seems to work.

    nvram set wl0_country=US
    nvram set wl0_country_code=US
    nvram set wl_country=US
    nvram set wl_country_code=US
    nvram set wl1_country=US
    nvram set wl1_country=US

    With a default install of the firmware some of those parameters are blank and filling them in for the 2.4 and 5 GHz antenna's seem to get them working properly.

    Hopefully two things will result from this...
    1. Someone will try this and it will work for them also
    2. I won't destroy my router because I am using 100 mW for Tx power ;)
  2. LanceMoreland

    LanceMoreland Network Guru Member

    I am watching this with interest. I have never been able to increase signal strength beyond what I am able to achieve using 0 (hardware default) on my E4200's.

    Using hardware default the router reports TxPower is 127 qdbm, 31.75 dbm, 1496 mW Override is Off.

    I know that Toastman and others claim that these numbers don't make sense but here is an web page that supports the numbers do correspond with each other and they do give me my strongest signal.
  3. kthaddock

    kthaddock Network Guru Member

    Well if you read that power is dbm and to get ex 10->20mW (power) is 3db
    and if you messure 500 mtr to 1000 mtr (voltage) over AIR is 6db.
  4. Dr Strangelove

    Dr Strangelove LI Guru Member

    I have a little perch 15metres(~45') from the E4200 and been monitor signal strength and tinkering with settings since having Toastman firmware installed approx six months.

    I get -59dB thru -63dB (2.4GHz) using inSIDDer and that's about it and when I checked the above settings, they were already set.
    Maybe being in NZ and not US I'm more prone to setting to NZ as we have 1-13 channels officially.
    I did set the transmit power to 20 (believe unless otherwise advised the default is ~42) and the signal strength dropped noticeable . From ~42 through to 100 you may get an extra 3dB, but it's so subjective it's hard to verify without proper monitoring equipment.

    If I turn my notebook (Dell DW1520 WiFi antenna built into monitor lid) a few degrees off the perfect angle and the signal can drop by as much as 10dB.

    One good thing about all this is if something is confirmed to improve signal strength I'll know as I'll get -58dB or better as a constant and I've never had that. Environmental conditions aside.

    My floor is approx -84dB(2.4GHz) and nothing competing on ch 1+5 (40MHz), mostly the 'others' are around -85dB or lower.
    5Ghz is -88dB floor and it's approx -70dB at 15metres.

    Again this is all subjective depending on the WiFi card you have in a given phone/notebook.

    I've also disabled afterburner and etc on my notebook and stuck to new world 802.11n settings, but do have mixed mode on the router for my 802.11g phone.


    Just my 5ยข worth.

    Oh and as an aside, I have a 150Mbps 802.11n 2.4GHz USB thumb WiFi (CNet CQU-906) and at the same 15metres it gets ~72dB which I thought was amazing considering it's size. And that's without using a wire strainer as an antenna. :D

    Update - Bit more tinkering and I do see some differences. Sometimes my Advanced WiFi setting show Australia as country and I just reset it in New Zealand, however, the signal strength does seem to drop a few dBm. Then if I set it back to Australia, the signal raises by approx 3dBm.

    Doh! As much hate to say it, It'll have to buy some VB, an Esky and a stubbie cooler, aye mate. Australians aye, no surprises there.

    I see in the latest firmware release notes the default country has now been set to SG.
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