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Changes between Version 5 and Version 6 of UserDocs/AntennaDiversity

Author:
msmith@cbnco.com (IP: 0.0.0.0)
Timestamp:
04/27/06 20:24:49 (13 years ago)
Comment:

recommend disabling tx diversity with only one antenna connected

Legend:

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  • UserDocs/AntennaDiversity

    v5 v6  
    1111Transmitter diversity works differently in that the driver needs to tell the radio which antenna to use. In madwifi-old the driver logic was to start transmitting to a station on the default antenna (lowest numbered) and then keep track of the receiving antenna for packets received from that station. If three consecutive packet receptions from a station occur on "the other" antenna then the driver changes the transmit antenna to match the receive antenna. The operation of madwifi-ng is probably the same, but this has not been confirmed. 
    1212 
    13 Apparently the switch that selects which antenna transmits tends to have about a 10dB-15dB attenuation on the non-transmitting antenna. So there is some power that goes to that non-transmitting antenna. Also, if you see fluctuations in output power levels of about that amount on one antenna, then it may be diversity kicking in... 
     13Apparently the switch that selects which antenna transmits tends to have about a 10dB-15dB attenuation on the non-transmitting antenna. So there is some power that goes to that non-transmitting antenna. Also, if you see fluctuations in output power levels of about that amount on one antenna, then it may be diversity kicking in. 
     14 
     15You will definitely want to disable transmitter diversity '''if you only have one antenna connected'''. Otherwise 50% of your broadcast and unicast packets (ARP, OSPF) will go out the wrong antenna. (See r1430, #326, #168.) 
    1416 
    1517== Controlling diversity ==