Feedback from Speakers

Archived from groups: alt.cellular.cingular (More info?)

I have a brand new Motorola RAZR V3 with Cingular service. What I am
noticing is that I am unable to use this phone in the same room as my
computer because I get feedback from my speakers. It sounds like
buzzing in pseudo-Morse code (it is not a solid buzz). This only
happens when the phone is powered up. I needn't be using it. I never
experienced this problem with my previous Motorola V300 and T-Mobile
service, so I don't believe the problem is the GSM frequencies.

Can someone tell me what is happening and how I can prevent this
problem in the future?
3 answers Last reply
More about feedback speakers
  1. Archived from groups: alt.cellular.cingular (More info?)

    On Thu, 09 Jun 2005 07:05:06 -0400, D. Harrison <dharr@optonline.net>
    wrote:

    >I have a brand new Motorola RAZR V3 with Cingular service. What I am
    >noticing is that I am unable to use this phone in the same room as my
    >computer because I get feedback from my speakers. It sounds like
    >buzzing in pseudo-Morse code (it is not a solid buzz). This only
    >happens when the phone is powered up. I needn't be using it. I never
    >experienced this problem with my previous Motorola V300 and T-Mobile
    >service, so I don't believe the problem is the GSM frequencies.
    >
    >Can someone tell me what is happening and how I can prevent this
    >problem in the future?

    It is indeed GSM that's causing the whiny buzz. Move your phone away
    from near the speakers and you shouldn't have this problem any longer.
    You'll also get this when you're on a newer phone with an electret
    microphone instead of carbon granule (like in the old Western Electric
    rotary and touch tone phones the 500 and 2500 series.)

    - - - - - - - - - - - - - - - - - - - - - - - - - -
  2. Archived from groups: alt.cellular.cingular (More info?)

    "D. Harrison" <dharr@optonline.net> wrote in message
    news:qd8ga15h2npp5mn4j5b9ddj13auv7pi6l2@4ax.com...
    >I have a brand new Motorola RAZR V3 with Cingular service. What I am
    > noticing is that I am unable to use this phone in the same room as my
    > computer because I get feedback from my speakers. It sounds like
    > buzzing in pseudo-Morse code (it is not a solid buzz). This only
    > happens when the phone is powered up. I needn't be using it. I never
    > experienced this problem with my previous Motorola V300 and T-Mobile
    > service, so I don't believe the problem is the GSM frequencies.
    >
    > Can someone tell me what is happening and how I can prevent this
    > problem in the future?

    That's RF from your phone, this has been discussed many times in this forum
    (see previous posts). Solution: move your phone further away from your
    speakers.

    bamp
  3. Archived from groups: alt.cellular.cingular (More info?)

    D. Harrison wrote:
    > I have a brand new Motorola RAZR V3 with Cingular service. What I am
    > noticing is that I am unable to use this phone in the same room as my
    > computer because I get feedback from my speakers. It sounds like
    > buzzing in pseudo-Morse code (it is not a solid buzz). This only
    > happens when the phone is powered up. I needn't be using it. I never
    > experienced this problem with my previous Motorola V300 and T-Mobile
    > service, so I don't believe the problem is the GSM frequencies.

    Actually, it's probably because the phone is operating on GSM 850MHz,
    which is likely what Cingular operates on in your area. T-Mobile is
    pretty much all GSM 1900. YOur speakers are susceptible to interference
    in 850MHz, and that's why you're hearing the data bursts coming from
    your handset where it didn't before on T-Mobile.

    > Can someone tell me what is happening and how I can prevent this
    > problem in the future?

    The current implementation of GSM operates in TDMA; that means that the
    phone will transmit in rapid on and off digital pulses in specific timed
    bursts. Other devices like speakers and CRT monitors tend to be
    susceptible to RF interference, and these data bursts will resonate in
    those devices, manifesting themselves as either a flickering monitor or
    those sharp buzzsaw noises you're hearing.

    If it's any consolation, Nextel's iDEN is even worse at it, and you
    would hear a loud pulsing hiss like a lawn sprinkler, instead of a faint
    buzz.

    As to preventing the problem in future; you can't really. Unsheilded
    electronics are pervasive because people like to be cheap in the
    equipment they buy (and cheap in the phones they buy, hence the
    transmitters aren't high enough quality to avoid spurious RF emissions).
    The only way to stop is to either change the affected equipment out to
    something that's better shielded against RFI, or to change carriers to
    something in 1900MHz, which appears not to affect your audio equipment
    as much.

    Another alternative is to switch to CDMA, or wait until Cingular
    converts to UMTS (which will implement WCDMA). The RFI will still be
    there, but CDMA lacks the time-slot/burst transmission arrangement, and
    so the resulting interference to be barely susceptible.

    --
    E-mail fudged to thwart spammers.
    Transpose the c's and a's in my e-mail address to reply.
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