Turn off your damned phone!

I love my iPhone. I really do.

There is, however, one thing I don’t like about it, a characteristic that (or so I’ve learned) the iPhone shares with many other “smart” phones, and that’s its annoying tendency to interfere with poorly shielded electronic devices. The phenomenon, known as radiofrequency interference, manifests itself as hysterical bursts of mid-frequency electronic buzzing that sound something like “dit-dit-dit-dah-dit-dit-dit-dah,” or Morse code on speed with a continuous buzz behind it. The problem appears to be most common with GSM-based phones, such as AT&T (the iPhone’s carrier), T-Mobile, and the old Nextel networks but is not limited to them.

I first learned of this phenomenon the day after I had activated my iPhone. I was sitting at my desk listening to my iTunes library, when the (now) characteristic buzz started up, drowning out my music as it poured out of my speakers. I figured out that I could shield the phone with my hand and stop (or at least attenuate) the drone, or I could put the phone in a drawer and risk forgetting to take it with me whenever I leave my office. I later noted the same interference when I tried to play my iPhone during the drive home using a cassette adapter. Oddly enough, there was no interference if I was not using the adapter to listen to music (i.e., if I was just listenign to the radio or a CD), implying that it was the adapter that was inadequatlely shielded, not the car stereo itself. Subsequently, I learned that, to be sure of avoiding this problem when using the iPod to play music, one needs to use devices certified to “work with iPod,” which apparently means their electronic shielding is up to the barrage of RFI that the iPhone produces.

Little did I expect to hear that same buzz here at the AACR during a talk.

I won’t say what talk it was. Suffice it to say that it was during one of the tumor angiogenesis sessions. It happened almost immediately after the speaker walked up to the podium to start speaking. I had noticed hints of it with the speaker before this one, but much quieter. In retrospect I think it may have been this speaker sitting at the podium waiting his turn; alternatively the speaker before him may have also had the problem, but not as loud. Be that as it may, as the speaker began his talk, first it started low, a relatively quiet howl underlying the talk. It was enough to be noticed but not yet really distracting. Unfortunately, it would not remain so.

As the talk went on, the well-known (and, to me, now hated) drone came back. Louder. So loud that at times it almost drowned out the speaker. Surely he must be aware of it, I thought. And then the friend I was sitting with pointed it out to me: The buzz appeared every time the speaker started gesticulating as he spoke. Clearly he knew what was going on, because I started to notice him putting his left hand on his hip whenever the buzz became too annoying, after which it would disappear for a while–until he started gesticulating again.

I wanted to leap up and yell: “Could you just turn off your damned phone so I can pay attention to your science?”

I felt sorry for the guy. Really I did. But I was also annoyed at him. He had clearly figured out what the problem was. True, it would have been somewhat embarrassing to have to take his phone out and turn the damned thing off, but that’s what he should have done. If he was clever about it, he could even have turned it into a little joke. (I hope that’s what I would have done.) Of course, now that I’m acutely aware of the problem from my own experience, I will always make very sure my iPhone is turned off or on “airplane mode” before stepping up to the podium to give any talk.

The really sad thing is that the talk contained some good science about tumor angiogenesis. Unfortunately, I can’t remember very much of it at all. All I do remember about it is that irritating GSM buzz.


  1. #1 navtej kohli
    April 16, 2008

    Is it true for only the iPhone or with all the phones that work with GSM technology?

  2. #2 Alex Whiteside
    April 16, 2008

    That “dun-da-dun dun-da-dun dun-da-dun” handshake signal is universal. It’s been warning me of incoming SMSes and calls via cheap TV and PC speakers since I was an undergrad. Gives you time to find the phone in your pocket, at least.

    In this instance I’m sure the guy was actually receiving SMSes or calls and was cancelling them through his pants leg rather than switching his phone off.

  3. #3 Julia
    April 16, 2008

    I’ve been hearing that sound any time a cell phone is near my computer speakers for about four years. It’s not unique to the iPhone. It always happens right before I get a call, but it also happens periodically without there being an incoming call. My phone, and my friends’ phones, were certainly not “smart” in any way, though I do think they were/are all on either Cingular/AT&T or T-Mobile.

  4. #4 Barry Leiba
    April 16, 2008

    Interestingly, I’m reading this while listening to a talk at a symposium, and the speaker’s phone just dit-ditted. Without pausing, he quietly removed his phone from his pocket and put it down away from the electronics. Very smooth.

  5. #5 Barry Leiba
    April 16, 2008

    And also…
    As annoying as the RFI is, I’d rather people just remember, when they’re using their computers as AV equipment, to log off their instant messaging services and turn off their screen savers.

  6. #6 Hans
    April 16, 2008

    Just last week this “GSM buzz” was mentioned on The Naked Scientists, and since I believe everything I hear, it must be true.

    That aside, it seems like a massive failure of etiquette not to switch off your phone while you’re giving a presentation. Giuliani may think it’s cute, but to me it appears more like the speaker would rather be doing anything else than being here, and will grasp at any opportunity to get away from the presentation. Way to show respect for your audience.

  7. #7 Orac
    April 16, 2008

    In this instance I’m sure the guy was actually receiving SMSes or calls and was cancelling them through his pants leg rather than switching his phone off.

    Or the phone could simply have been checking in with the tower, as it does periodically. I get that on my phone without necessarily receiving any SMSs or calls.

  8. #8 M1
    April 16, 2008

    yeah, definitely not unique to iphones or smart phones. my medical school has a wireless mic for lecturers, and we hear that noise all the time. the regular professors know about the problem, but students have to speak up and tell the clueless guest lecturers to please turn off their phones.

  9. #9 JDP
    April 16, 2008

    That “GSM buzz” is common to all GSM phones. I get it through my radio speakers at random intervals and when calls come in to my RAZR. It only really bothers me when I’m on the phone (it can be pretty loud depending on my location in the room), but I’m not listening to the radio then anyhow.

    Interestingly, my old radio did not have this problem. I suspect the reason is that my old radio was analog with a simple wire antenna. My new radio is digital and has a big amplified antenna. The receiver is much more sensitive.

    I don’t understand why this presenter didn’t just put his phone down somewhere. How hard would it have been to throw it in the lectern?

  10. #10 Chris L
    April 16, 2008

    First time I heard the noise was during a DVD. My friend says “I’m about to get a phone call” and sure enough it starts ringing a few seconds later.

    I’ve heard the noise in podcasts or radio shows too, recorded as part of the show, so presumably, some recording devices are susceptible too.

  11. #11 Cherish
    April 16, 2008

    I suspect the reason is that my old radio was analog with a simple wire antenna. My new radio is digital and has a big amplified antenna.

    Actually, it probably has nothing to do with the antenna. The noise you’re getting probably comes from the high frequency switching of the digital electronics, and they can emit a lot of noise.

    FCC regulations only specify emission requirements and not susceptibility requirements (unlike the EU). On the other hand, there isn’t much you can do about something that’s an intended receiver…and apparently a pretty sensitive one. It sounds like even with restricted emissions on these other devices, these phones can pick up a lot of unintended noise.

  12. #12 Cherish
    April 16, 2008

    Oops…should have rephrased that last part of the comment. Sounds like these phones can emit a lot of unintended noise.

  13. #13 Brian X
    April 16, 2008

    It’s certainly something I’ve run into. I do sound at the local community access TV station and every once in a great while we get it over the speakers.

    (Incidentally, for a similar effect, try charging up the flash on a disposable camera next to the antenna of an FM radio. It’s sort of a sine wave oscillation that gradually slows — think freq=sin(1/x) if you’ve got a graphing calculator nearby.)

  14. #14 eric
    April 16, 2008


    You’re right that it’s the phone trying to find a tower. You can get into situations where the reception is spotty or where you’re switching cells often (ie driving) where it happens much more often.

  15. #15 Sigivald
    April 16, 2008

    To be even more technical, the interference in question isn’t strictly caused by it being GSM, but by TDMA, the multiplexing scheme GSM (and almost all 2G systems) uses.

  16. #16 magista
    April 16, 2008

    I love physics, don’t you?

    Our school has a ‘no cell phones during class hours’ policy, and that sound has become one of my techniques for spotting and confiscating phones (in addition to the unmistakable screen glow if you try to use them when I have the lights off and am working with a projector). It’s tempting to set up simple speaker circuits all around every classroom I work in now…

  17. #17 AndreasB
    April 16, 2008

    Yup, that’s a normal occurence. The da-dit-da-dit-da-dit is just periodical signaling (phone probably just reaffirms its existence in the network cell), a constant hum/whine is a constant connection as in an ongoing or just starting call. So it would seem that the speaker was getting calls he then cancelled. However, it might also be a insufficiently denoised vibration motor if such things are allowed to be sold.

    Analog audio signal lines (i.e. from the source to the amplifier) pick that up because they’re low voltage so the phone signals can make a significant impression. And if you’ve got an old fashioned CRT instead of these new fangled LCDs, you can make the image skip and wobble, too! Probably that also works on LCDs that are connected via analog lines to the graphics card.

  18. #18 Leni
    April 17, 2008

    I’m shocked!

    Orac wrote:

    I later noted the same interference when I tried to play my iPhone during the drive home using a cassette adapter.

    A cassette adapter? If that was your car, get thee to Best Buy (or wherever) and spend the $200 bucks or so you’ll need to get yourself a new car stereo! Or are you still trying to get through that Lord of the Rings Trilogy on tape that you bought 14 years ago?

  19. #19 Ian Hendry
    April 21, 2008

    My work colleagues and I used to moan about this 15 years ago when it happened to us on wholly unsophisticated GSM phones. I say unsophisticated; it sounds like they were some 15 years ahead of their time in the RFI sense! I don’t think I’ve seen a car with a cassette player in it for that long either.

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