How far do I really need to keep FP3 from my body?

I’ve always resisted having a smartphone at all, until last year when I purchased a Fairphone 3 – and I love it! My children think it is too big to fit into their pockets, and I didn’t care until I came across this talk by a high profile former presidential advisor on public health ("The truth about mobile phone and wireless radiation" -- Dr Devra Davis - YouTube
“The truth about mobile phone and wireless radiation” ) … and suddenly I wondered : how far away from my body do I really need to keep this FP3 ?

Under “RF exposure information & Specific Absorption Rate” on the FP3 it says 10mm.

It would be a pity to make life less convenient by switching on/off wifi all the time or not putting your FP in your pocket, if in a particular situation/configuration it doesn’t make a huge difference. So my real question is : is there any way we can make some very basic measurements with off-the shelf electronics to check out radiation exposure in certain locations around the phone (and apparently it is the changes in intensity as a function of time are that matter).

At some point I’ll also ask the Fairphone company whether they are actively pursuing this issue – and I don’t mean pursuing by adjusting legal notices, but really in the design phase of their FP.

Hi @SylviaV Welcome to the forum

I don’t know of any but will have a look, it would be interesting.

However on the dangers which are largely based on theory and statistics it may be worth getting an understanding of what is happening.

The effect or force from electromagnetic radiation is not just relative to it’s ‘power’ of the transmitter but the frequency. Double the frequency and double the power all other things being equal. So wifi @ 5GHz is twice as powerful as wifi, and bluetooth and your home microwave all at 2.4Gh. Mobile networks work the the range on 1 to 3 Ghz.
Now this second kind of power due to the high frequency can more easily travel though the body and hence effect more cells and smaller parts of the cells for example.

The body is a bit like a series of fine nets and the smaller frequencies get through finer nets and can get to the chromosomes and atoms etc.

Very high frequncies like x-rays can pass through the body. In passing through some may dislodge the atomic structure and cause burning. To the outside skin this is not so damaging but to essential organs the issue is dies the body have the ability to repair quickly or will is create a mutated cell than can be cancerous.

The emf/radio waves of phone are millions of time less powerful in this second sense than even ultraviolet or normal light so the effiect is a) it won’t travel as deep, and b) bit can’t effect atom structures and chromosomes etc.

To get a better idea of the difference in this power to disrupt via frequency rather than the strength of the signal, which can burn like a microwave, look at this table.


Look at the line SHF 3GHz plus it is 100,000 times less powerful than light (see the three coloured bands)

Now be aware that on a square metre of earths surface gets approx 1Kilowatt of power per hour. So you can see why ultarviolet which is tens times more powerful may cause more damage.

Note now the wavelength. Light is around 1 micrometre 100,000 times smaller than the phones wave and so can interact with smaller components of the body, a bit like resonance.

Now consider the strength of the signal from a phone. It can hardly produce 1 Watt but true is is localised. If you are concerned line your pocket with aluminium foil.

The other way to look at this is to measure the damage done generally by all forms or radioactivity and put the phone in perspective.

Here is a table make by the manufactures of tritium exit signs for cinemas etc. The idea is that they contain radio active Hydrogen that can keep the fluorescent coating in the lamp alight for ten years 24/7 and what if one breaks.

Look at this and note the lowest is from Chernoble and Nuclear fallout, Tritium somewhat in the middle, cigarette smoking, as it pulls Polonium into the lungs is far worse. I won’t go through the list as you can read.

The issue is I am more at risk from the sun and the food I eat than I am from ŧhe phone.

So yes the phone may cause damage, but thousand s of times less than me working outside in the sun without a hat on my bald head etc.

By the way, although the tables are pickups off the internet I used to work on radar in the Royal Navy so am familiar will radiation dangers.

The SAR specification is designed to show how much radiation in terms of watts absorbed by 1Kg of body tissue, and around 1 is the preferred high level though some phones are nearer 2.

So to summarise I am 65Kg so that would equate to being able to absorb 65watts continuously without due concern.

Sitting in front of a wood fire is far more damaging as is siting in the sun.

The 1 watt per kilo does not take into account the area, hence the distance of the phone is relevant.

If Fairphone state the SAR at 1cm then at 0.5cm it will be 4 times stronger at .25cm 16 times at 1.25 mm 64 times.

The area covered maybe some 2cm squared, I’m not sure of the exact aerial dimensions.

How this effects the bodies tissue depends upon the type of tissue, it it’s fat not such a big deal it will just eb absorbed as heat, if muscle it could be an irritant which could become addictive and a turn on.

Next to the brain it will be a significant pattern of information that will be dealt with as an addiction and usually compensated for, like any other music.

The main issue is that the frequencies do not have the high energy that can disrupt chromosomes and atoms. The radio wave is around 10cm and may resonate with anything of that size and octaves to a decreasing degree, but there is no electrically sensitive body part anywhere near that size, unless two neurons in the brain are exactly that far apart (10cm) and have a common connection, which is so unlikely that we will probably have completely abandoned this planet and be living on Mars before such an event is recorded.

Here’s a link to a site that shows the level of concern that some people may find appealing/comforting/worrying/overthetop.


I wondered what kind of confidence this kind of credential should really give me, so over to Wikipedia (yes, I wonder what kind of confidence this should really give me in turn, but anyway, it’s a source, too) … and lo and behold: “These claims are disputed and have sometimes been labelled ‘alarmist’.” … which of course is true for almost every environmental concern ever raised at first, to be found justified later.

What I want to say is: Somebody on the internet said something (or wrote books) … we’re doomed? This is not how it works for me.
The scientific process isn’t perfect, but it has a long history of figuring things out methodically over time. I’ll go with that. If Devra Davis is right, what she says will most probably become scientific mainstream and action then should be based on that (yes, as if politics acted on the environmental scientific mainstream for decades, but that’s a different issue).
How else do we want to operate and not in effect run around like headless chicken?


This is an ever and again promoted topic but these people do not have the technical backround to spread proven facts. - As always :face_with_monocle:

To keep it simple lets do a comparsion with a microwave, as the radiation wavelength is at least somewere in the same range.
If one put 1kg meat into a microwave and cook it with 1000 W power, how long will it take?
A phone have just 2 W of power and this only when it transfers data or on a call. In the meantime only once in a while it establish a short radioconnection. How long would it take to cook the same amount of meat with these circumstances?
And now lets transfer it to the human body, lets say 50kg. How long would that take?
I assume every one get the point here.
From my side of view carrying around a mobile phone, even for some hours, will hardly affect the human body.


Just to be more mathematical.

1000w at 8cm is the same as 32w at 4cm >> 5.6w at 2cm >> 2.4w at 1cm >> 1.5w at 0.5cm

So if depending upon whether you have the back of the phone, where the antenna is, or the front you may get between 2 to 1 watt.

Sunshine at 1000w/square metre is 1 watt for every 3.2cm square of the body exposed, it is also has a small ionising radiation effect on the cells, not just warming.

The antenna is probably much less than 3.2cm square so arguably more radiation from the phone for that exposed area of the body.

However the sunlight wattage is that actually received at skin level whereas the phones radiation is that recommended at 1cm from the body.

Still the only issue would be if the skin adjacent the phone got hot like being in the sun, which would be notable. I’d be more worried about the an unstable Li-ion battery burning through my trousers than any warmth the radio may produce.

I did the comparsion just for creating more sense for the situation.
1000W is the total power consumption of the microwave. What power really get the electrons swinging I do not know. I assume maybe a third.
So your mathmatical calculation is also not correct :wink:

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Hmm! the calculation is correct given the wattage after all you don’t define if that is input or output power.

Though as you state if it was 1000w of input power it doesn’t transfer to radiated power.


What are you referring to by electron swinging.

The radiation isn’t electrons swinging there is a magnetron that is the radiation funnel.

The food or body also dosen’t have swinging electrons, the emf is absorbed by the water usually in the cells and vibrates and hence warms.

Also the efficiency of a 1000w input microwave may well be as low as 50% in a dryish food and 75% in watery foods.

However my calculation was based on the simple idea that if 1000watts is presented as the force/energy then it has to be the figure used for calculations, everything else is speculation and variable, but not the maths :slight_smile:

As a summary

I was trying to draw the OP’s notice to the fact that the ‘1000w microwave’ radiation effect is dependent upon the distance of the radiation source to the receiver not the actual level of radiation in any instance.

I.E the maths is about the distance to keep the phone not the radiation level of the phone.