Why Your Clock Radio Is All Abuzz About iPhones

blackbearnh wrote in with a story that's not really about the iPhone, but if your office speakerphones beep like mine does, read on: "If you own an iPhone, you may have noticed that it has a distinct and very annoying effect on clock radios, computer speakers, car radios, and just about anything else with a speaker. The folks at O'Reilly Media aren't immune, so they set out to discover just what is it about iPhones that makes them such bad RF citizens. The iPhones aren't the only bad apples in the cell phone basket and there's not much you can do about the problem. We're really in an interesting time in that there has never been so many high-powered personal transmitters just wandering loose in the world."

Comments

Psh

[waffledoodle]

As I understand it, all Apple products have a distortion field.

Re:Psh

[Detritus]

You wouldn't get interference if your television receiver wasn't a POS. We know how to design and build receivers that can operate in hostile RF environments, we just choose not to, because it's cheaper to build the POS.

Re:Psh

[Mateo13]

It's not the phones, it's the douche bag field emitted by iPhone owners.

Nothing to see here.

[HeavyD14]

It just looks like someone has never had a GSM phone before.

Re:Nothing to see here.

[Spazztastic]

Mod parent up. Cell phones have been doing this since my old Nokia to my new Blackjack II.

Re:Nothing to see here.

[HotNeedleOfInquiry]

Aircraft COM receivers are particularly sensitive to cellphone interference. If I forget and leave mine on when I fly, I get a very distinctive da-da-daaa da-da-daaa da-da-daaa every few minutes over the radio. From any cell phone.

Re:Nothing to see here.

[Bogtha]

Yeah, to give some idea of just how non-news this is, I first noticed this effect when Slashdot was called Chips & Dips.

Re:Nothing to see here.

[HeavyD14]

Yeah, those are called Chokes: http://en.wikipedia.org/wiki/Common_mode_choke

Re:Nothing to see here.

[Midnight Thunder]

Mod parent up. Cell phones have been doing this since my old Nokia to my new Blackjack II.

Yup and with some computers you hear static over the speakers before the cell phone rings.

Re:Nothing to see here.

[Anonymous Coward]

It's not a magnet. It's ferrite.

Re:Nothing to see here.

[realisticradical]

You've left your cell-phone on when you fly!!! You know that it emits dangerous pilot-killer-rays!

Re:Nothing to see here.

[fermion]

It is not just GSM phones. My old RAZR had the same problem. At meeting, anytime a phone rings we get all sorts of interference with audio.

Re:Nothing to see here.

[Anonymous Coward]

Links are occasionally helpful.

Re:Nothing to see here.

[Anonymous Coward]

As long as it isn't da-da-da daaa-daaa-daaa da-da-da. :-)

Re:Nothing to see here.

[JWSmythe]

    I don't know how this ever made it to any news source. I'm trying to remember how long ago the first time I noticed it. It's been at least 10 years. My first phone that did it was an old Nextel.

   

Re:Nothing to see here.

[sexconker]

SOS for the Morse intolerant.

Re:Nothing to see here.

[orclevegam]

As the AC pointed out it's not a magnet, it's a ferrite bead. This is a very common thing, and many cables come with one installed already. Just looking at the monitor sitting on my desk I can see a pair of beads on it's VGA cable (one at each end), and they're very common in most high end speaker systems. For cables that don't have them you can pick them up from various places in the form of snap-on cylinders which can either be directly clamped onto the cable, or alternatively you can wrap the cord around the bead once or twice before clamping it, which will hold it in place on the cable and also serves to improve the filtering slightly.

They're a very simple passive device that works by disrupting high frequency RF passing through the cord. Since any large (long) conductor can function as an antenna, most cables are really just giant antenna, so adding a ferrite bead is a really cheap and simple way to counteract this. As for interference within a speaker itself (that is, not arriving by way of the speakerwire used to hook it up) there's not much you can do other than putting a Faraday cage around the speaker, or just moving the source of noise farther away from the speaker.

Re:Nothing to see here.

[OrangeTide]

Indeed. It is a well known phenomenon. I end up turning my blackberry off or leaving it in the kitchen on game/movie night because it makes all sorts of funny beeps on the surround system. I don't think people realize how powerful the transmitter in a cell phone is, and that it is not unique to iPhone.

Apple customers tend to be rather picky and vocal about any possible defect with Jobs' perfect little products.

Re:Nothing to see here.

[Anonymous Coward]

there's not much you can do other than putting a Faraday cage around the speaker,

...how about putting a Faraday cage around the phone instead?

GSM Buzz

[russotto]

It's not just the iPhone. It's any GSM phone. Google "GSM Buzz". Meet the "GSM Devil", which relies on this interference to tell you you're phone is about to ring. http://shop.mopodmania.net/product.sc?categoryId=1&productId=15

Re:GSM Buzz

[nine-times]

Correct, lots of cell phones do this. If people are noticing it more with the iPhone, it's probably because people are more likely to want to hook the iPhone into audio equipment than with other cell phones.

Re:GSM Buzz

[bloodninja]

Meet the "GSM Devil"

I put on my robe and wizard's hat.

All GSM phones do that!

[Nick Ives]

Maybe it's just because you guys aren't used to GSM cellphones but over here in the UK everyone recognises that noise. Anytime you put a mobile next to speakers you get that noise.

Welcome to the 1990s, America!

Re:All GSM phones do that!

[russotto]

Funny how this post got +5, Informative for the same thing you just said, yet your post is sitting at +1, Troll.

Slashtip: Including a link to a silly gadget is always worth karma. Bashing the US can go either way.

Do those people think Apple reinvented...

[sznupi]

...everything regarding cellphones? Including, in this case, sometimes annoying side effects?

This is nothing new...especially if, on any other phone, you have also kept semi-constant GPRS connection.

PS. Rearranging speaker cables/etc. eliminates the problem anyway...

My Nokia 3610 did this also.

[bigtallmofo]

As others have said, this really is a GSM issue and not an iPhone issue. The sound I hear from my computer speakers with my iPhone is identical to what I heard from my Nokia 3610 which is about as un-iPhone as a phone can get without being better described as a rock.

Seriously - the interference sound is identical.

My only concern really is what is this doing to my neurons, rods, cones and assorted other presumably sensitive body parts. I don't care about a goofy sound coming from my computer speakers every once in a while.

FCC Rules Part 15

[doas777]

whatever happend to the label on the bottom of everything, which states that:
"This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) the device may not cause harmful interference, and (2) the device must accept any interference received, including interference that may cause undesirable operation."

obviously the folks that made my PC speakers obeyed those rules, so why is apple getting away with breaking condition 1?

Re:FCC Rules Part 15

[leighklotz]

whatever happend to the label on the bottom of everything, which states that:

"This device complies with Part 15 of the FCC rules. Operation is subject to the following two conditions: (1) the device may not cause harmful interference, and (2) the device must accept any interference received, including interference that may cause undesirable operation."

obviously the folks that made my PC speakers obeyed those rules, so why is apple getting away with breaking condition 1?

The iPhone isn't operating under Part 15. It's licensed. Your cell provider holds the license from the FCC. They paid a lot of money for it; remember the spectrum auctions that raised billions. It's your speakers that have to live with the licensed world, not the other way around.

The same is true for broadcast radio, TV, police, fire, ambulance, business radios, taxi dispatchers, amateur radio, military, and even foreign licensed broadcast systems. Your speakers have to live with it.

You might try (1) using twisted pair instead of zip line to your speakers and (2) using ferrite bead clamps, a few turns wrapped around both ends of the speaker cable. But it probably won't help, as it's likely your speakers internal amplifier is picking up the signals directly, as they're cheaply made (see TOA) and poorly shielded.

Re:FCC Rules Part 15

[wramsdel]

Leighklotz is exactly right, but it gets even worse. Even a Part 15 device, using similar modulation to the GSM phone, could likely cause interference to your speakers. I have a DECT phone, compliant with FCC Part 15, sitting next to my computer speakers, and it creates a nice buzz when it's searching for the base. That's not the phone's fault, I'm sure they're transmitting all their energy in the allowed band, but nonetheless my speakers are rectifying that RF energy and amplifying the resulting envelope. The "device may not cause harmful interference" part of the Part 15 regulations refers specifically to spurious emissions outside the permitted band(s) of operation. Unfortunately, inexpensively made or carelessly designed electronics, which constitute the bulk of consumer offerings, often don't include much protection from interference. Regardless of whether the interfering device is operating properly or not, these devices will suffer.

Re:the cause could be put into the summary

[russotto]

Or, in other words, a 217Hz signal is amplitude modulated onto the GSM signal. Some electronic devices (like amplifiers) incidentally demodulate the 217 Hz and convert that to sound. 217Hz is well within the human audible range, thus... dutuh, dutuh, dutuh, dutuh, dutzzzzzzzz.....

(since it's a 217 hz square wave you get lots of harmonics as well)

Re:Huh...

[russotto]

Maybe it's because the computer speakers are so old that they're actually still shielded (unlike most today?)

Yes, speakers which are magnetically shielded to prevent affecting CRTs will also likely reject the GSM buzz.

The clock radio would only pick up the GSM buzz if the speaker was on (radio or buzzer); when it's off, no problem.

Not on 3G, EDGE only

[yabos]

The GSM buzzing is all GSM phones but I noticed on my iPhone that using 3G it goes away. From what I've read, the loud noise is caused by rapid turning on/off of the GSM transceiver which creates EM pulses.

You beat me to it

[jshackney]

I was going to chime in along those lines as well. This is hardly news. When the weather is ideal at departure and destination, I usually tell my pax they don't have to turn their phones off. When the weather is bad and I'm going to be shooting the ILS to minimums, the last thing I want to hear is seven or eight phones ticking in my headset from the initial approach fix to the DA.

Some phones seem to be worse than others and it sounds like the iPhone may validate the FAA's position on cell phones.

Re:the cause could be put into the summary

[Anonymous Coward]

...and if you're really good you can tell the difference between a 2.5G location update, an incoming call, a GRPS attach/detach and 3G noises.

Yes, alright, 'Getting out a bit more' is on my plan, I just didn't get around to it yet.

Re:It seems to be AT&T more than anything...

[flatulus]

Perhaps the AT&T cellsite is further away from your location than the T-Mobile cellsite. Hence, your phone has to "talk louder" for the AT&T cell to hear it.

No cellular provider would intentionally instruct your cellphone to emit more power than required, because it would be self-defeating. Excess transmit power just means unnecessary interference to nearby cells on the same frequency. The cellular protocols provide a means for controlling the power of a handset up and down as needed to get "just the right amount" of RF energy at the cell tower's receiver.