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  1. #1
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    Wi-Fi interferring with BT Headset

    Does anyone have any issues with Wi-Fi interferring with Bluetooth Headsets? Mine is really crackly at home and work, both Wi-Fi, but in my car its perfect.

  2. #2
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    As far as I understand it 802.11 b/g, Bluetooth, and one of the cellular bands operate at 2.5ghz. There's bound to be issues. Much is the same with other devices in the home, microwave, portable phones, etc. For instance I got a 900mhz phone instead of the newer 2.5 ones so that it wouldnt interfere.

  3. #3
    I'm a total loser and I've been banned!!!
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    Bluetooth operates at 2.4GHz. WiFi operates at 2.5GHz (802.11b/g).

    The bandwidth area being similar is not revelant... both technologies find "channels" that are free to use. BT uses frequency hopping spread spectrum.

    The crackling is probably related to something else such as the positioning of the BT phone at the house or the BT stack on the phone.

    E

  4. #4
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    I run WIfi at home and work. No crackling at home, work or in the car. HS820 crackled everywhere but HBH-300 did not (on the old 3500C patch). I returned the HS820 before the ROM upgrade.

  5. #5
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    Sorry, youre wrong Ehud.

    http://www.cnet.com/4520-7364_1-105323-1.html

    802.11b is the most widespread wireless LAN standard. It describes a wireless LAN that operates in the 2.4GHz frequency range with a data transmission speed of up to 11Mbps using spread spectrum technology. (This specification was also known as Wi-Fi, but that term now encompasses newer standards such as 802.11a and 802.11g.) The 2.4GHz range is already crowded, however, with microwave ovens, cell phones, PDAs, Bluetooth, and other devices, so signal interference is a risk.


    802.11g describes a wireless LAN that operates in the 2.4GHz frequency range. It provides a data transmission speed (over short distances) of up to 54Mbps using orthogonal frequency division multiplexing (OFDM) technology. The 2.4GHz range is already crowded, however, with microwave ovens, cell phones, PDAs, Bluetooth, and other devices, so signal interference is a risk.
    /edit
    To the OP, I found this via quick search on google, so it may not answer all your questions, but they are out there. When doing my searches I noticed you can configure your AP to use only certain channels, but I lost where that page was.

    http://www.rfmd.com/bluecoexistence.asp
    With nifty pic-goodness.

    Last edited by johnnye; 03-20-2005 at 08:19 PM.

  6. #6
    Registered User IvanLasston's Avatar
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    Ehud was wrong about frequencies but he is right about the "channels". The only problem you'll get is if a 2.4GHz source overdrives the LNA and floods out the signal of interest.

    Just to run a test I had my wifi sdio card on while using bluetooth. No interference.
    AT&T Jailbroken Iphone 3G 2.2

  7. #7
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    Bluetooth is a frequency-hopping technology, 802.11b is direct-sequence spread spectrum (DSSS). This means that 11b transmits across a wide channel (22MHz), while Bluetooth rapidly hops through a sequence of narrow channels. So when "collisions" occur, bluetooth tranmissions will likely experience interference, but 11b should not be affected since the "noise" should be averaged out.

    Most 2.4GHz phones use frequency hopping spread spectrum (FHSS) technology that operates within the 2.4GHz spectrum. FHSS hops from frequency-to-frequency across the entire 2.4GHz spectrum. 802.11b WLANs, on the other hand, use direct sequence spread spectrum (DSSS), which transmits within approximately one third of the 2.4 GHz spectrum. Because FHSS jumps across the entire spectrum while DSSS stays in only one portion, a FHSS 2.4GHz will clobber an 802.11b network, causing interference or even failure. (Bluetooth has less amplification than cordless phones)

    I didnt read the full PDF, but the NIST (National Institute of Standards and Technology) compiled this:
    http://w3.antd.nist.gov/pubs/mswim01.pdf

    I believe 802.15 is on the drawing board to correct these problems.

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