| Static / Noise from GSM phone over car's speakers
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| marco_polo |
Has anyone else noticed that if you have a GSM phone (Cingular, T-Mobile or AT&T Wireless) and when you are making a call or when the phone is about to receive a call there is a "rat tat tat" type noise over the MDX's speakers. I just got a new MDX with HFL and I literally have to put my bluetooth phone as far away from the radio as possible or I get the intermittent noise. Both my Blackberry (AT&T) and my cell phone (Cingular) which are both GSM do it, so it's not the phones. I don't think there is a fix, i'm just wondering if anyone else has seen/heard this noise over their speakers.... Almost sounds like a machine gun. It is the most noticable if you put the phone in the little cubby hole under the radio (provided you don't have a RES)
Marco |
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| trstack |
Yup...my Blackberry and wife's Moto phone (both GSM) do it in the MDX as well as in my Maxima. Since I keep my Blackberry in a cradle right next to the radio in the Maxima and use a Bluetooth headset, I just turn the radio off in the Maxima when I'm on the phone.
In the MDX, I keep my Blackberry or phone far enough away from the radio that it's not a problem, thanks to Bluetooth and HFL. |
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| hollafat08 |
| i have verizon thank god, but those carries do that noise not only in cars but in house hold radios. They interfere with the frequency. I notice it all the time when people go into my car or are around in my house. At least you can tell when u have an incoming call or if your phone is picking up a signal cause it makes that noise.. lol I dont have that problem though cause i have the best service verizon. |
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| eRauL |
Actually, GSM is TDMA-based.
To make it more confusing, IDEN, which Nextel uses, is GSM-based.
As for the buzz, look at this Wireless Design Magazine article
In TDMA and GSM cell phones, the most notorious voltage-supply noise comes from the RF stage switching on and off. The GSM phone switches on and off at a rate of 217 Hz. When the RF power amplifier switches on, high current is drawn from the power supply. As a result, the power supply dips by up to 500 mV. An audio amplifier with poor PSRR will cause more than 217-Hz harmonic clicking noise in the speaker.
The RF stage usually switches on and off when setting up a call; for example, when a call is coming in.
This buzzing problem has nothing to do with the cellphone transmitter, which is usually between 850MHz and 1900 MHz..
I have had this buzzing problem on all kind of audio-system, from cheap handsfree headset to high-end Yamaha AV Receiver. BTW, try it on CRT monitors. You'll see some interference on certain resolution :-) |
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| wing2299 |
| the noice does not happen on my previous 03 CRV nor BMW but the MDX. |
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| XStatic |
| I just switched to Cingular and haven't noticed it in the car but I have heard it on my PC speakers and my cordless phones. |
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