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wrt54g antenna diversity ?

Discussion in 'Cisco/Linksys Wireless Routers' started by t4thfavor, Aug 2, 2005.

  1. t4thfavor

    t4thfavor Network Guru Member

    i have an idea...
    i would like to set up a point to point link with 2 WRT54G ap's

    my question is, is the antenna diversity feature of the ap able to use one of the antennae to run the link while using the other to feed a small hotspot?

    if so this would let me maintain a hotspot on either end of the liink as well as the link...

    is the ap firmware even capable of doing such things perhaps via WDS or client mode...

    if so what firmware?
  2. t4thfavor

    t4thfavor Network Guru Member

    bump bump all

    come on nobody knows i dont think tech support would even try to help me....

    howabout it jim?
    anyody know?
  3. 4Access

    4Access Network Guru Member

    Here's a copy & paste from a post I made a while back:

    You'll probably find some better info by searching for "antenna diversity" at the BroadBandReports.com forums.

    Example thread: Dual purpose for two antennas
  4. davidsonf

    davidsonf Network Guru Member

    It will work, but you won't like the results.

    As others have pointed out, the "diversity" with a WRT54G is a hot switch arrangement. The receiver will continually check the other antenna for signals, and pick the best antenna on an incoming signal. The transmitter is connected to the antenna last used for receive. And that's where the devil gets into the details.

    If it is receiving from the directional antenna, and it just happens that the next packet needing to be transmitted is intended for a client connecting on the omni antenna, and the client just happens to be located where the directional antenna has no signal at all... everything will come to a screeching halt because the packet will be sent but never received and then everybody waits until a timeout occurs.

    The antenna will not be switched until something is received on the omni antenna! At that point, the next attempt to send that packet will be on the right antenna, and it will start going again. Of course the next packet going to the client on the directional antenna will suffer a similar fate, because it will get sent on the omni antenna. That may or may not be received, but if it is it will probably be at lower signal strength that with the directional antenna, and that might, for example, cause a downward shift in speed. Suddenly your 54Mbps connection is running at 4Mbps, just like it did before you paid big bucks for that fancy directional antenna! Opps.

    Hot switched dual antennas only work if they are virtually identical in gain, directivity, polarization, and orientation. That will generally mean that signal variation between them will be less than about 6 dB, and you will actually benefit from switching between the best received signals.

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