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Are there any studies that compare WiFi and cellular data usage, in the home, over time?

Mainly I've heard that WiFi uses more battery (so it should emit more radiation) but OTOH it feels like 3G/cellular needs to use higher power to reach the antenna (which is much farther away than the wifi router.)

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    From the research I've done to answer previous question about Wifi and 3G power usage on another SE site, I found that 3G uses less power to maintain a connection without actively transferring data (i.e. standby) but when actively transferring data, 3G radio had to emit higher-powered signals since it is designed for higher range and thus takes more power. Also, 3G radios adjust their power output according to the distance of the base tower to the device. Note that battery usage does not directly translate radiation. – Lie Ryan May 11 '11 at 13:08
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    @Lie Ryan: Indeed radiation doesn't really correlate to battery usage - current WiFi encryption is rather heavyweight (definitely not designed for power-efficiency), plus WiFi emulates Ethernet (with all its quirks and chattiness), whereas 3G data usually goes over PPP; both would contribute to more CPU time, and thus higher power draw - without necessarily contributing to radio power output. – Piskvor May 11 '11 at 15:34
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    If you're talking ionising radiation, the sort that can actually harm you, they both expose you to about the same amount (zero) – GordonM Jun 15 '15 at 10:08
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It looks like you might be confusing some terms here... using more battery/power doesn't necessarily translate into more or less radiation. The radiation strength is determined by the frequency that the devices operate at, i.e., the frequency of the radiation they emit.

3G devices (in the U.S.A.) don't really have a set frequency, but rather will operate at various levels ranging from ~800 MHz to just shy of 2.4 GHz (more if you're using Bluetooth or 4G phones). WiFi signals, on the other hand, share the same general frequency as microwave ovens at right around 2.4 GHz.

But because of how we use these signals, it becomes a battle of distance and duration. Cell phones are right next to our skin for short bursts of time, while routers or laptops generally sit far away from us for extremely prolonged periods of time. The UK's Health Protection Agency noted in 2007 that:

sitting in a wi-fi hotspot for a year results in receiving the same dose of radio waves as making a 20-minute mobile phone call.

But the thing to pull away from all of this is that you probably don't have to worry too much about this kind of radiation having any seriously dangerous long-term (cancerous) effects on you (provided you're not walking around with wireless devices taped to every inch of your skin). That's not to say long term exposure to low-level radiation might not have other adverse health effects, but it's hugely unlikely to be cancer. Any radiation below ultraviolet (radio, microwave, infrared, and visible light) is non-ionizing and won't penetrate bone, meaning it can't break down atoms (and consequently DNA, leading to cancer) and it can't get to your sweet, delicious brain. The "do power lines/microwaves/cell phones/next radiation-emitting-device-that-most-people-don't-fully-understand give you cancer?" studies are all, as they'll always be, resoundingly inconclusive.

Even the newest WHO review of cell phones (described by CNN with a typically alarmist title) somehow makes the claim that cell phones are "possibly carcinogenic to humans," despite the fact that "The WHO work group did not find that there was sufficient evidence linking cancer and environmental or occupational exposures with microwave energy," implying that the possible carcinogens must come from the phones themselves, and not the radiation.

Also worth noting is that the WHO group also puts coffee, pickled vegetables, and tea into the same classification. There's a lot to be worried about in the world; this probably oughtn't be too high on anyone's list.

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    W.r.t your first paragraph. Radiation strength = emission power = antenna circuit power = battery drain. (But, as Piskvor says, WiFi may use heavier encryption which would increase battery drain w/o affecting radiation power). Also, I'm specifically looking for data on smartphone use. I.e. should I surf the web with wifi or cellular at home? (I.e. this would mean I turn on Wifi all times when at home, i.e. each evening and the weekends.) I usually turn off the phone at night, btw. – Macke Jun 2 '11 at 18:50
  • @Macke: I think part of the problem here is in terminology, that all of us have been talking about slightly different things. To clarify: radiation "strength" has nothing to do with battery drain. The strength of the emitted radiation is a function of what the device is trying to do, not how hard it's trying to do it. Trying harder might cause it to emit a greater quantity of radiation, but not a greater "quality." The problem is, as Lie Ryan said, battery usage still doesn't translate directly to quantity of radiation. The phone is doing other things, all contributing to overall drain ... – erekalper Jun 2 '11 at 19:29
  • ... so it's really going to vary from phone to phone. You could test your phone by letting it run an intensive app until the battery is dead, once with WiFi off and once with it on, but again, that won't be a perfect measure (and you'll almost certainly see it die much faster with WiFi on). So that's why I explained about the various "qualities" of radiation emitted, as that's more useful to examine. 3G is less than WiFi, and neither is widely considered dangerous by any proven/known standard at all. – erekalper Jun 2 '11 at 19:29
  • Ideally, I'd test with my phone and measure the amount of electromagnetic radiation energy coming off it. (Energy = Freq * amplitude, IIRC). I appreciate the info on radiation being non-ionizing, which is often left out of the debate, and so, for both Wifi (hi-freq, low power) and cellular (lo-freq, hi-power) the equation might even out. The quote about the wifi hotspot is really interesting, but not conclusive w.r.t. surfing on the phone. I'm accepting your answer though, as it gives a lot of good answers to the problem in general. – Macke Jun 2 '11 at 19:40
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    @Macke: Close on the energy equation. It's actually E = h * f, where E is energy, h is the Planck Constant, and f is frequency. That equation's not independent of wavelength/amplitude, though... frequency is described by f = v / λ, where v is velocity (v = c in this case, the speed of light) and λ is wavelength, so you could write E = h * (c / λ). But I digress. Best of luck with your tests! – erekalper Jun 2 '11 at 19:56

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