Wi-Fi, Microwaves, visible light and radiation in general

17 Feb 2012, 9:19PM

Most people don't really seem to understand electro-magnetic (EM) radiation very well. This covers the whole spectrum including radio waves, microwaves, visible light, infra-red, ultra violet, x-rays, etc, etc. They're all the same thing really, just differing wavelengths (same as differing frequencies) and hence differing energies.

But lets start from the start. First pyramids that you can place by your bed and are claimed to block out or protect you from cell phone radiation are rubbish. Cell phone radiation is the same as visible light, e.g. the cell phone is like a pulsing light bulb. Imagine a light bulb in a room, throwing out light in all directions, now imagine placing a pyramid somewhere in the room and it sucking up and protecting you from the light. Dumb aye? The light goes straight past the pyramid and its only protection is the shadow it casts. Hence to protect yourself from (any form of) EM radiation you would need to cover yourself in pyramids. How anyone can think these work is beyond me (I had a flatmate once who believed he got headaches from his cellphone and had such a pyramid by his bed at night time).

So a cell phone is like a light bulb. Just like a light bulb the light is more intense the closer you get, e.g. if you put your hand around a light bulb its quite hot but further away and you feel nothing. The cell phone is the same. If you enclose your hands around it then all the radiation from it is emanating out through your hands. The differences between normal light bulbs and a cell phone is the frequency of light. The cell phone frequency will mostly go through your body and only a small amount is absorbed. The amount that is absorbed is not strong enough to break DNA or cause cellular damage, it only imparts a small amount of energy, e.g. it heats you up from the inside. So its similar to microwaves really, well similar to all light really, infra-red (aka the heat your body gives off, or that you feel from a fire) will heat you up, its just that due to its wave length it doesn't penetrate very far and so heats just the outside of the skin. But microwaves and cell phone EM penetrate deeper and so heat up the inside of things.

So this sounds terrible, we're being heated up from the inside. Well yes and no. The sun heats us on the outside all the time, its natural and our bodies can handle some degree of heat increase.

So what I find interesting is the increasing coverage of Wi-Fi. We are blanketing ourselves in it. We put small emitters in our house that pulse out EM in all directions constantly, while we are awake and while we sleep. Its considered safe, but its also similar to taking your microwave oven, dialing down the power to super low and stripping the protective cover off, then leaving it running 24/7. E.g. you would gain some very small increase in heat due to the EM. Again sounds alarming, but it will be orders of magnitude less than the heat gain you get when you take a hot shower or sit by the fire. So what is the issue? Is there any? Damage only occurs at high levels, just like exposure to high levels of light (e.g. under a magnifying glass) can damage you. So keep your levels low.

So what about the proliferation of Wi-Fi devices? I sat at the mobile teams desk at work. All 8 PCs there were Wi-Fi capable. There were usually at least 3 or 4 ipads, maybe 6 or so smart phones and misc other Wi-Fi enabled devices. We have a Wi-Fi network at work and most peoples phones use this (as it saves money compared to 3G). So are we multiplying the radiation we get. Well yes but radiation received is inversely proportional to the distance from the source. E.g. further away is better. Maybe 4 or 5 iphones taped to your head while making a call would be bad, 4 or 5 in the room is probably still ok.

So finally to drive the hypochondriac among us insane lets think about buses... We have 30 people in a metal can, metal largely reflects EM so you would get internal reflections, still some gets out as you can still use your phone in the bus. So 30 phones in a metal can, all pinging the cell phone towers, and smart phones these days are often downloading data. Just thinking about it gives me a headache ;)

Finally when your cell phone is communicating with the cell phone tower we tend to forget that the signal is not a direct line of communication but is going out in a sphere. So the same distance away on your opposite side (from the tower) is getting the same strength signal as the tower is. Its both brilliant (it travels through walls and doesn't need to aim at anything) and massively wasteful at the same time.

It makes you wonder, would a directional cell phone signal be a lot less power hungry than the current system?