WRT54G - Power (transmit) output adjust.

Discussion in 'Wireless Internet' started by MP, Jun 17, 2004.

  1. MP

    MP Guest

    Is there a way to lower the AP's output signal?
    I want to limit the wireless range.

    I've read that the WRT54G puts out 19mW. I want
    to know if 15 or even 10 mW would suffice.

    I've also tried to use small home-made
    antennas (www.freeantennas.com) but it tends to
    do the opposite - increase directional power.

    Any ideas?
     
    MP, Jun 17, 2004
    #1
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  2. MP

    Barry Jones Guest

    I'd be curious as to other's reactions to it, but I'd try to put two soup
    cans over the antennae, cut enough holes in it to get a connection, then
    stop cutting. If heat build up is a problem, cut a hole in the top. You can
    use a piece of styrofoam in each can to help keep them positioned well.

    There were some hacks to lower the power output of the old Linksys WAP11,
    but I prefer to leave the unit intact. If there are network problems down
    the road, you don't have to worry about whether your hacks are part of the
    cause.
     
    Barry Jones, Jun 17, 2004
    #2
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  3. MP

    AnToNio Guest

    If that were the case you would not be able to get any signal anywhere!
    You probably are mixing mw and dbm.

    The output is somewhere between 64 and 84 mw.

    Why would you want to limit output where everybody is trying yo
    iincrease output?
     
    AnToNio, Jun 17, 2004
    #3
  4. MP

    Jim Sanchez Guest

    The easiest (and best IMHO) is to flash the router with the code from
    wifibox.net ( Firmware Version: v2.00.8
    Wifi-box.net Release Version: 2.00.8.1i-pre6.wfb 22/01/2004 ) which
    allows you to increase and decrease output power. Plus it give you some
    very nice other features.
    Jim
     
    Jim Sanchez, Jun 17, 2004
    #4
  5. MP

    Jim Osborne Guest

    Sveasoft makes firmware which makes the (WRT54G) power output adjustable.
     
    Jim Osborne, Jun 18, 2004
    #5
  6. MP

    Vitali Esau Guest

    This is not right, in my router (WRT54G DE) the default antenna power is
    set to 18mW. After a firmware update with
    http://www.f4.fhtw-berlin.de/~s0503018/Satori_v2_2.00.8.7sv-pre3.bin
    you can increase or decrease the power.
     
    Vitali Esau, Jun 18, 2004
    #6
  7. MP

    AnToNio Guest

    Incorrect!!

    Like I said, you are mixing dbm and mw, which are 2 totally different
    thing. 100 mw is about same as 20 dbm.

    Below, the email I got from Linksys when I needed to know exact numbers:

    =======================================
    Thank you for contacting Linksys Technical Support.

    Model Number RF Output Power (dBm)

    1. WRT54G v2 18dBm
    2. WRT54G v1.1 15dBm
    3. BEFW11S4 v4 15dBm

    Should you have further clarification, don't hesitate to email me back.

    If you have further questions, please contact us at (800) 326-7114 or
    send us an email at so that we may further assist
    you. Please use this phone number given as reference for future support
    calls.

    Have a pleasant day!


    Sincerely,

    Aldrin S. Casas
    Linksys – A Division of Cisco Systems, Inc.
    Product Support Specialist
    800-326-7114
     
    AnToNio, Jun 18, 2004
    #7
  8. MP

    Vitali Esau Guest

    Hi,
    I didn't formulate correctly. Here a second try:
    There are two different output power values we talked about. There is an
    internal transmitting power of the router (which I talked about) and a
    total transmitting power (which you talked about). The total
    transmitting power is calculated like this:
    (Linsys approximate values)
    internal transmitting power of the router (18,0 mW ~ 12,6 dBm)
    -
    cable and ports losses ( ~ 4 dBm )
    +
    antenna gain ( ~ 9 dBm)
    _______________________________________________________
    total transmitting power (63,1 mW ~ 18,0 dBm)

    So I talked about the internal transmitting power, wich you can change
    after the firmware update.

    Best regards
    Vitali
     
    Vitali Esau, Jun 21, 2004
    #8
  9. MP

    Vitali Esau Guest

    You can for example look at: http://www.zytrax.com/tech/wireless/calc.htm
     
    Vitali Esau, Jun 21, 2004
    #9
  10. MP

    Some Guy Guest

    Thanks for everyone's help!

    I managed to download a firmware patch that allows me to
    adjust the power output from the default of 28mW all the
    way down to 2mW.

    Using my Sony Clié with a built-in 802.11b interface, I
    was able to quickly survey the range and got pretty
    much the coverage I wanted without sacrificing in speed
    over errors.

    I'm doing more surveying today to tweek the AP.

    Cheers everyone!
     
    Some Guy, Jun 21, 2004
    #10
  11. MP

    AnToNio Guest

    Untrue!

    If you start internally with 18 mw then you will never be able to
    transmit more than 18 mw. Worse even, it will always be less. The only
    gain you can reach with the antenna is that of bundling all power into a
    small direction instead of transmitting all around.

    The 18 dbm (Linksys figure) is aproximately 84 mw and believe it or not
    it is absolutely impossible to get an almost 5-fold increase by any(!)
    antenna. The antenna is only able to limit the region it sends and
    thereby limiting the spreading its power.
     
    AnToNio, Jun 21, 2004
    #11
  12. A 20dB antenna will give you an ERP in the direction of interest of
    100 times the input power. There are plenty of 24dB gain antennas...
     
    William P.N. Smith, Jun 22, 2004
    #12
  13. MP

    AnToNio Guest

    And that increased power will ONLY exist in a small sirection where at
    the same time other direction will have nil. All that these antennas do
    is bundling the total power and send into a small direction.

    Compare it with mobile TV transmitters, the parabole bundles the signal
    into a rather small beam and a bit besides that beam there is no signal
    at all.
     
    AnToNio, Jun 22, 2004
    #13
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