Hi

Just got myself a set of wireless headphone for a present. I really like them but I have a small concern. Are there any health issues? As it is using radio waves transmitted to the phones whilst on my head is it similar to using a mobile phone? As I wear them for long periods of time it just worries me.

As they are only receiving the radio waves and not transmitting does this make it safer.

Thanks in Advance.

[NicolasB]

There is no proven link between mobile phones and any health risk. Even if there is such a link that's because the phone itself is broadcasting a signal within a couple of centimetres of your brain that has to be powerful enough to reach a mobile phone mast anything up to a mile or two away. You're taking about standing several meters away from a radio source that is designed to have a maximum range of tens of meters. Simple inverse-square-law considerations should tell you that you don't have anything to worry about.

Unless of course the aliens use the signal to control your brainwaves.

[Chris Muriel]

Simple inverse-square-law considerations should tell you that you don't have anything to worry about.

Spot on! If only the public in general and particularly those complaining or protesting about local Cellphone masts would realise this .
I have given up explaining this to various non-technical acquaintances & NIMBY types.
(Yet I don't get complaints about my ham radio antennas - several of them transmitting at frequencies from 144 MHz up to 10 GHz on a 20 foot ploe emanating from a 30 foot mast).

Chris Muriel (G3ZDM).

[NicolasB]

What's even funnier is just how much electromagnetic radiation at all frequencies people are constantly bathed in without their even realising. By comparison the radiation from a mobile phone mast is trivial.

Interesting fact: when you fly across the Atlantic you absorb about as much ionising radiation as you would having a chest X-ray.

Simple inverse-square-law considerations should tell you that you don't have anything to worry about.

Oh right. Should have listened harder at school.

Thanks for your answers. I was slightly concerned that I was in effect strapping two mobile phones to my head for several hours a day. And yes - not proven yet as you say. I just want to make sure I won't be the one to prove it.

I shall listen in total reasurance from now on.

Cheers

Paul

[NicolasB]

I've possibly been a little too sarcastic in this thead. I hope no one has been offended, but if they have then I apologise....

The inverse square law refers to the way that the intensity of a propagating wave (among other things) decreases with distance from the wave's source, assuming that the wave is spreading out in three dimensions. Intensity is defined as power per unit area (e.g. Watts per square meter). If you imagine sound or light or radio waves coming from a point and radiating outwards in all directions then the energy emitted at any one moment will occupy an expanding sphere. The surface area of the sphere is proportional to the square of its radius - the total area that the energy is spread out over is proportional to the square of the distance from the source. Thus the intensity of the signal falls off in proportion to the square of the distance from the source: twice as far away and the intensity divides by four, three times as far away and it divides by nine, four times as far away and it divides by sixteen, and so on. That means that if you go from a source that is one centimetre away from your head to one that is two metres away then the intensity of the radiation is reduced by a factor of 40,000. And the transmitter for wireless headphones is far less powerful than a mobile telephone anyway.

The other major factor in mobile phone radiation (apart from distance to source) is frequency. Mobile phones operate near microwave frequency. The magnetron in a microwave oven spits out a 2.450GHz signal to get the water molecules in your food all hot and bothered. Mobile phones now operate in this range (1.8GHz for PCM systems like Orange). Of course, the power levels involved are of different orders (750W for an oven, 0.3W for a phone). Your cordless headphones are operating at ~100MHz or 0.1GHz and at power levels lower than a mobile phone.

The other factor involved is exposure time, but again, I doubt that a lifetime of wearing a pair of wireless headphones will make any bit of difference to your mental health, although your personal image may suffer

PS And in answer to your question, yes it does make a difference that they are only receiving the signal, but only because the transmitter is further away from you (hopefully) than the receiver, along the lines of what NicholasB was saying about distance.