Troubleshooting Phone-Induced Clicks in Speakers

[Phymath]

When ever my cell phone rings near any type of powered speaker I can hear clicks in my speakers, I was wondering if the clicking is occurring because the induction coil in the speaker has a current induced from the changing magnetic field in the radio waves transmitting the call? If so what's the relation between the pulsing clicking sounds and the frequency of wave.
This also occurs on certian CRTs the image gets distorted when the phone rings but not during the conversation...

 

[pack_rat2]

When ever my cell phone rings near any type of powered speaker I can hear clicks in my speakers, I was wondering if the clicking is occurring because the induction coil in the speaker has a current induced from the changing magnetic field in the radio waves transmitting the call?...

The RF field from the transmitter is far too weak to do that. And if it COULD happen, EVERY phone call being sent out by that transmitter would do it. You say the speaker is "powered." I assume you mean it's connected to or inside a piece of equipment that's turned on. In that case, the audio amp that supplies the signal to the speaker could be picking up EM radiation from the "ringer" circuit in the phone.

 

[neil_m]

im curious pack rat, I've experienced the samething.
while the phone is on a call, it won't interfere, while it is ringing, but ONLY when it is ringing from an incoming call, (ie NOT just previewing a tone[which should be going thru the ringer circuit, no?])
I have tested it with mycomputer speakers, and it causes interference when a call is incoming. I hear the interference on the speakers even before the phone begins to ring.

 

[CharlesP]

im curious pack rat, I've experienced the samething.
while the phone is on a call, it won't interfere, while it is ringing, but ONLY when it is ringing from an incoming call, (ie NOT just previewing a tone[which should be going thru the ringer circuit, no?])
I have tested it with mycomputer speakers, and it causes interference when a call is incoming. I hear the interference on the speakers even before the phone begins to ring.

All these things sound strange to me. I was the audio guy on Motorola CDMA and other cellular phones, made in Libertyville, IL. I made hundreds of ringers ring. So far all I have ever heard is the TDMA buzz in speakers on nearby audio equipment. The reason for the buzz is that the cell phone transmitter is turning on and off at a rate of several hundred Hz during a phone conversation. The RF envilope is detected by a susceptible low signal part in the audio equipment and that noise is added to the regular audio path. TDMA buzz is a problem in some phones and it was my job to get rid of it. The RF carrier was 1.9 GHz. TRansmitter power was 0.1 Watt. Distance to susceptible audio equipment was 5 feet.

 

[neil_m]

wow, cool.
Well, i haven't gotten too technical, (cause i can't, haha) but i have done it with my phone which is on a TDMA network.
But, i would piss a friend off who left his phone ( nokia GSM network) next to his speakers by his bed. When he was trying to sleep I kept calling the phone and his speakers, ( i THINK it was the subwoofer tho), would just buzz , and bother him.
It is only incoming calls. The receiving phone causes the interferene. and it goes away if the receiving phone answers it stops.
I just tested using a GSm and a TDMA phone.
But now i got a different sound...like morse code...lol.. from the receiving GSM nokia..
that any help?
by the way how would you fix that?

 

[chroot]

I'm not an expert on cell phone strategies, but I thought the speaker-clicking was the phone responding to the tower's seek by transmitting a short burst of high-power signals announcing its availability and negotiating its required transmit power. A second or so later the cell phone actually begins ringing.

- Warren

 

[CharlesP]

I'm not an expert on cell phone strategies, but I thought the speaker-clicking was the phone responding to the tower's seek by transmitting a short burst of high-power signals announcing its availability and negotiating its required transmit power. A second or so later the cell phone actually begins ringing.

- Warren

I just verified similar behavior with my Nokia. It goes tick tick tick then buzzes in the FM radio. Any chance you worked for Motorola in Ft. Lauderdale and Ft. Worth?

 

[600burger]

I'm not an expert on cell phone strategies, but I thought the speaker-clicking was the phone responding to the tower's seek by transmitting a short burst of high-power signals announcing its availability and negotiating its required transmit power. A second or so later the cell phone actually begins ringing.

- Warren

Thats what i always thought it was. I've since unplugged my sub until i want to use it. Sometimes it buzzes and the phone won't ring at all, perhaps a nieghboor?

Also, i recentlly got a cieling fan the runs on a 350MHz FM remote and have had problems with erroneous opperations (i.e. turning on or off without input to the remote). I know that just about everything could be doing that, but is there any quick way to find out what it is? or sheild the fan?

Thanks,
-Burg

 

[CharlesP]

Shielding the fan will kill the correct signal too, so that doesn't help.
Trying to find a rare transient signal is like trying to catch a spy transmission. If you have a spectrum analyzer or a radio that happens to tune that frequency you might just snoop for a long time. Good luck.

 

[philocrazy]

the audio amplifier picking up an RF with modulation digital or analogue
will only amplifier the audio frequency component, thus the signal could
be coming from anywhere in the phone, i thing it is RF that causes this
inteference or a beat of RF frequencies with audio frequency modulation
if audio amplifiers were picking up audio frequency signals that easily it
would make them highly unstable and useless

 

[ShadowLurks38]

i have the same problem!
i have a nokia too.
car speakers.. and the stereo at home makes that noise.
at times it won't ring but the speakers will still rattle.

 

[bassplayer142]

I have the same problem. I have found that it is from the transmitter and not from recievieing. It will start beeping on car speakers or amplifiers before my phone rings. I figure it to be somekind os interference.