Why Your Clock Radio Is All Abuzz About iPhones 397
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."
FCC Rules Part 15 (Score:5, Interesting)
"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:Nothing to see here. (Score:5, Interesting)
Re:Nothing to see here. (Score:5, Interesting)
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:FCC Rules Part 15 (Score:2, Interesting)
You beat me to it (Score:5, Interesting)
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.
What's happening in Europe? (Score:3, Interesting)
The US's Part 15 only applies to RF emitters; devices that don't emit RF at all, like audio amplifiers, don't need Part 15 certification. Part 15 doesn't say anything about sensitivity to interference.
The European Union, however, does regulate sensitivity to interference under the Electromagnetic Compatibility Directive. [conformance.co.uk] So the EU tries to address the problem.
The EU standards require a test for susceptibility to high power AM, FM, TV and airport-type radar signals. Those were viewed as the worst case when the directive was published. Electronics that's not designed for it is likely to crash when faced with a megawatt airport radar at a few hundred meters. (Remember, with most radars, the peak power is huge but the duty cycle is low.) But the EU directive doesn't address nearby TDMA sources. That's probably something the EU will have to address.
There's something to be said for spread-spectrum emitters, like WiFi and Sprint PCS phones. They have a broad enough output spectrum that they tend not to interfere with much.
really (Score:2, Interesting)
when a text message arrives, older nokias beep
da-da-da daaa-daaa da-da-da
Re:Nothing to see here. (Score:2, Interesting)
Yup. And your cell phone in GTA IV is a GSM phone: just before it rings, you get that distortion on the vehicle radio.
You also get a burst of distortion when you leave the tunnel, as the phone re-syncs to the network. (Which is weird, because both the Holland and Lincoln tunnels have lossy transmission line-based cell repeaters in them. They even have regular radio repeated into the tunnel--but they'll interrupt regular broadcasts for tunnel information.) (And now I don't remember if the GTA IV phone works in the tunnel, which would make it even more weird.)
Re:Nothing to see here. (Score:3, Interesting)
Nope. RTFA, Part 15 devices (consumer electronics, not the phones) have the following regulations:
1) Cannot interfere with devices in a "higher priority" classification (such as a licensed transmitter)
2) Must accept interference from devices in a "higher priority" classification, such as a licensed transmitter. Cell phones are, effectively, licensed transmitter. The user themselves doesn't have the license, but the carrier does.