it seems whenever im near speakers that are turned on and i get a cell phone call, they start ling. is this bad? why does it happen? thanks.
Let me guess, it’s a Nextel? At my office whenever someone uses a nextel my speakers pop and sometimes my computer locks up. Grrrrrrrrrr. My coworker says that nextels operate on such a high bandwidth, or frequency or whatever ya call it that it interferes with the frequency of other electronics.
:smack: Uhhh…I’m not sure why I really responded. I guess I don’t have a good answer for you. sorry
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It’s perfectly normal. Whenever you get a call, your cell phone sends an acknowledgement signal back to the cell tower so that the system knows your phone is on, in network, and available to receive a call. The electronics in some audio equipment can be affected by this signal and produce the sound you hear through the speakers. This is common with computer speakers when people leave their phones on the desk near them.
Is it not also to do with the satelite checking the location of the phone that makes the dugga dugga dugga noise if it’s near speackers?
My phone frequently does this about once an hour.
Yes, every now and again, your phone will send out a sort of “Hey, here I am!” signal to the cell network to let it know where you are. It will also do this when you turn it on. This helps the cellular network locate your phone faster when a call comes in.
How exactly does the effect work, on a physics level? Is the radio signal strong enough, and at just the right frequency, to induce a current flow in the wires leading to the speakers??
(I’ve also noticed that when my tungsten W palmpilot goes into wireless data mode, I can see horizontal lines moving quickly down and flickering on my monitor. 
)
It’s not affecting the speakers directly. It’s affecting the electronics in the amplifier the speaker is connected to. The signal from the cell phone is picked up by wires and circuit traces, rectified and amplified, and sent out through the speakers. The signal from the phone is relatively weak (~100 mW), but if the phone is nearby, it’s stong enough to cause the sound you hear. You’ll find if you disconnect the speaker from the amplifier, the sound goes away.
Kind of a random aside, I’ve always liked that my phone did that to speakers. It always happens a few seconds before my phone actually rings, so it serves as an advance warning before the phone goes audible. It makes my X-Box go all screwy, which has come in real handy. (Noise happens-pause game “Hi Honey…what? No I’m not playing video games, I’m cleaning like you asked…”)
I usually keep my phone next to my monitor (well, one of my monitors, anyhow). Often, the picture on the screen will go all wavy just before the phone rings. A handy early-warning system similar to Cluricaun’s.
Is this also the mechanism whereby those little flashy antenna knobs, desktop holders, and assorted carrying chains “know” to blink when a call is incoming?
Yep. Only their circuitry is specifically tuned to the band(s) cell phones operate on.