Since I neither want to annoy nor impress strangers with a cutesy cellphone chime, I keep my phone on ‘vibrate’ mode. (I especially don’t want to be like a typical Taiwanese woman who leaves her phone buried in the oblivion of her purse such that after 5 minutes of louder and louder ringing, she still hasn’t found her phone.)
Anyway, I’m a little surprised at the strength of the magnetic field produced by this vibrating phone:
I use a small, travel mouse on my notebook computer. A few times now, my cellphone has rung, and although about 40 cm away, it has induced a field in my mouse wire strong enough to pull the mouse toward the phone.
This field is also strong enough to shunt my MP3 player into shutting off (crashing), possibly by reversing electron flow in the circuitry. In this case, the phone is also about 40 cm away.
In this age of magnetic resonance imaging (MRI), magnetic bracelets and airspace saturated with electromagnetic radiation, maybe this is no big deal; but doesn’t this “cellphone magnetism” seem relatively powerful and harmful? Will a tumor grow from my body in the shape of ZhongHua telecom’s logo? :shock:
I experienced the same thing yesterday. I have a G4 17" PowerBook. I connect the Logitech RF wireless optical mouse to it through a USB transmitter. My phone was on the table, “set to stun”. The EM field (or whatever) disrupted the use of my mouse. I didn’t answer quite yet, moved the phone a few feet away, then had a connection to my mouse again.
This may sound like a dumb question, but how would the vibrate mode or ring tone affect the strength of the magnetic field? The only difference is whether you’re notified of the call via a speaker or a little vibrating mechanism in the phone; the call signal shouldn’t change, right?
Mobile phones do tend to effect monitors and speakers if they are close when you turn it on. Don’t think it’s a magnetic field, have you ever seen a magnet that can pull something 40cm away ? that would rip your fillings out if you held if to your face, erm… if your fillings were made of iron. Jeremy points very hard at the word ‘wireless’ in his post mentioned that a mouse that uses radio waves is effected by another thing that, uses erm… radio waves.
Transmitters have a tendency to also broadcast at power power on harmonic side bands. It only effects things 40cm away while the main signal travels (loads of ?) kilometers. Some of these weaker signals are audio frequencies, and can be picked up on speaker wires acting as arials.
And mouse wires.
Phones use a much stronger signal when in use (making a call, turning it on)
Two things related to this: the vibrating alert is nothing but a tiny motor with a piece of plastic off-axis, thus causing the vibration when turned on. Natually motors use magnetic fields to function, i.e. make the thing turn.
Ringing tones do not affect the field strength but when the phone is alerted (i.e. starts ringing) it will start to communicate with the system - and this happens on full power. Most obvious when you use a cell phone in a car close to the radio.
Furtheremore, at a time interval set in the switch, the system will check if a phone is still “alive”, i.e. turned on. Again the phone will send messages back at full power, causing probable interference to other electronic equipment close to it. Furthermore this also happens when the phone will hand over from one cell to another, mostly when you move but also possible when you are stationary.
This should also explain why you should not use your cell phone in hospitals and aircrafts.