Some interference is due to badly shielded wires or components, but some is just the result of too many gadgets crowded into a limited spectrum. Radio-frequency interference occurs when the signal emitted by one device gets unintentionally picked up by another-creating audible noise or a compromised connection. "We know, however, that things go wrong." Or to rephrase, things go bzzt-baba-bzzt-baba-bzzzzzzzt. "The people in the regulatory business produce standards for emissions and standards for immunity, or susceptibility, that should match, so that nothing emits more than anything else can tolerate," says Brian Lawrence, executive director of the International Association for Radio, Telecommunications and Electromagnetics (iNARTE). It issues regulations that cover both a device's "noise"-unintended, useless emissions, like those from a shoddily shielded microwave-and its susceptibility to interference from other gadgets. The 2.4-GHz microwave overpowers the 2.4-GHz router and the laptop gets confused.įor decades, the FCC has tried to prevent this. "And then you come along with a source that's creating electromagnetic fields that weren't intended to be in its environment." Like a noisy engine in the background of an audio recording, radio-frequency interference is the result of a device "listening" for one signal at a specific frequency and "hearing" another. "Consumer electronic devices are designed to be used in a certain environment and interact with electromagnetic fields," says Carnegie Mellon electrical and computer engineering professor James Hoburg. And with so many gadgets hanging around in such a narrow range of frequencies, things can get crowded.
#How to block stereo tools from accessing internet Bluetooth
Many routers, along with all Bluetooth devices, transmit at 2.4 GHz. Wireless home phones broadcast at 900 MHz, 1.9 GHz, 2.4 GHz and 5 GHz.
Cellphones, depending on the carrier, communicate at 850 MHz, 1.7 GHz and 1.9 GHz. This, a thin, patchy section of the electromagnetic spectrum below 5 GHz, is where our gadgets live. (High-school physics refresher: Wavelengths get shorter as frequency gets higher, and a 1-GHz wave measures about 12 inches.) Range, antenna size and cost requirements conspire with stringent government regulations to relegate most personal electronics to an even narrower range of frequencies. We use only a portion of the spectrum for wireless communication, the broad swath from about 30 Hz to 300 GHz. So what is it? How can you stop it? Radio OveractiveĮlectromagnetic radiation lies behind everything from gamma rays to visible light to your kid's walkie-talkie. RFI has been an irritant throughout mankind's love affair with electronics, particularly with wireless gadgets. RFI takes many forms, and they're all ugly: A humming microwave chokes a Wi-Fi connection a baby monitor brims with noise an audio recording made with a laptop fizzles and pops. What you experienced, in other words, is radio-frequency interference, or RFI. That's because what you've just heard is the noisy pulse of a cellphone's transmitter, amplified by either the station's studio equipment or your car's stereo. Within moments a cellphone will ring, either in the radio studio dozens of miles away, or inside your own vehicle.
The jarring interruption is as familiar as it is mysterious. No, not your favorite tune, but your least favorite sound: a bzzt-baba-bzzt-baba-bzzzzzzzt that pierces through your car-stereo speakers. Then, after a moment of pregnant silence, you hear it. After an eternity of chatter and commercials, the radio DJ is about to play the song you've been waiting for.
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