| GSM noise from cell phones [message #64489 is a reply to message #64352] |
Mon, 25 October 2010 11:45   |
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Wayne Parham
Messages: 18845
Registered: January 2001
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Illuminati (33rd Degree) |
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This is actually a switching noise, an RF signal generated by a cell phone that uses the GSM network when communicating with the cell tower. AT&T and T-Mobile are the major carriers that use this kind of signaling. Poorly shielded amplifiers sometimes detect and amplify this signal, causing the weird clicking or pulsing sound just before your cell phone rings, during a call and when you're sending or receiving a text message. It also happens when the phone is trying to register with the system, like when you move between towers.
Phones from Verizon/Alltel and Sprint/Nextel use the CDMA network, which doesn't use the same pulsing radio frequencies as GSM phones. They usually don't generate the same RF noise, and so aren't usually a problem when used near small amplifiers, intercoms or amplified speakers. However, world phones that use both CDMA and GSM networks will generate this noise when communicating with a GSM network.
Moving your phone away from your intercom, amp or amplified speakers will reduce or eliminate the noise. Better amps with RF shielding don't usually have the problem. An easy test is to put your phone near the amp in question and send it a text message.
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