Wifi power levels compared to mobile phones.

[farmerste]

Hi all, i have been reading about health and safety concerns about wireless networks, and also i wanted to compare them to mobile phone networks.

And before anyone says we have covered this many times here, i am approaching this from a different angle.

 

Mobile phone facts :-

 

Most phone masts transmit around 50 to 100 watts of power per transmitter, that is the white can shaped drum that you see typically.

 

Most mobile phones transmit around 1 watt of power, and some 3g,4g phones can peak around 2w of power.

( please note though this is next to the head )

 

if you measure the power at ground level from a mobile phone mast ( single transmitter- i.e 1 white drum ) the power at 50m from a 10m high mast will be around 100mW ( remember that figure , one tenth of a watt)

 

Phone masts do not transmit in even directions, most of their signal is angled downwards toward where users would be, and if you were in an hot air ballon passing over the signal would be weaker than if you were below the mast.

 

Wireless access point facts:-

 

the maximum allowed power output of a wireless access point in europe is

100mw ( one tenth of a watt)

 

the signal strength of wireless access points can vary in different areas of the surroundings depending upon model design and aerials attached etc.

 

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Both phone masts, and wireless access points , and the power they transmit are subject to laws of physics, i.e they are subject to the inverse square law, which is basically flux density decreases proportionally the further you get from the device omitting it.

 

SO WHAT AM I ON ABOUT you might well ask ??

 

well the point i am making is that sitting next to a wireless access pont is the same as sitting 50 m away from a mobile phone mast. i.e same power levels (but if your mobile phone mast has multiple transmitters this power reading will be higher )

Although different carrier frequencies may be used depending upon age of equipment etc. most newer wireless access points use the same frequency as your domestic microwave. also the lower frequency used by mobile phones can penetrate into the human body easier than the higher WiFi frequency. So does that mean Wifi is safer , or do we just need a larger dose to produce a noticeable boilogical effect ?

 

Now scientists tell us that the levels when you are further away from WiFi are so low that they must be safe , but they cannot prove they are, although tests have been done on animals etc.( but can an animal tell you it has a headache? or feeling of unwell ?)

 

There seems to be lots if scientific bodies studying this and giving various findings, but after looking at them, i am suprised that there has never been a full epedimiological study of the occurances of cancer with proximity to mobile phone masts. some authorities/organisations/groups have done though, see below :-

 

http://www.starweave.com/gallery/

 

Now if you notice the distances from tranmitters that incidents occur you can see that they are much greater than 50 m, and a reading of 100mW .

Plus if you take into account the ruduction of power due to building penetration the power levels must be much lower. But what are these levels?, are they the same as being a few metres away from a wireless access point i wonder?? And then you have to think about the wireless transmitter in the device/laptop you are using, because that tranmits too !

 

i think until we can see a map similar to the one above showing occurances of cancer in proximity to transmitters for the whole country, we will never get more research done. Are these incidents ocuuring purely because those areas are heavily populated, and these are just normal but tragic outcomes of life.?

 

but the one thing i would urge you to find out is what distance would the parents of the children in your school allow a mobile phone mast to be placed ?

before you go and flood everywhere with WiFi, as a report into this may well be on the horizon.

 

p.s i have spent ages looking on the net for info, and reading boring documents etc, and my conclusions are, whilst a little poison over a long time can do the same as a large dose, a low noise level over a few days does not make you deaf !

 

But why are the outputs of WiFi limited to 100 mW ??? the questions just keep coming really .........

 

hope this is of use , and please note, i am not frightened of being wrong, as the truth is only your findings to the best of you abilities :-)

[EeEk]

But why are the outputs of WiFi limited to 100 mW

 

is this not simply low power to stop them all interfering with each other? I remember CD radio way back in the dark ages being limited to 4w and I’m sure that was just to stop everybody interfering with each other.

 

but the one thing i would urge you to find out is what distance would the parents of the children in your school allow a mobile phone mast to be placed

 

We’ll find out soon….local council are planning a LAP centre here with microwave link and 2 segments similar to a mobile phone antenna….its not been to planning yet but does require full planning permission….they are expecting some trouble

[farmerste]

surely it would be better to have just one wifi point per school, rather than lots of small ones?, after all why not just crank up the power if the signal is weak in certain areas ?

 

sorry i was not having a 'go' at you there, it just doesn't make sense to me, and what is happening in the real world ( e.g cancer occurences ) seems too much of a coincidence to me?

 

i have added a doc version of my initial rant, if you would like it, although i do think it reads a bit 'doom and gloom' hopefully it might help surface a few answers.

[enjay]

p.s i have spent ages looking on the net for info, and reading boring documents etc

 

With respect, I think that the HPA have spent far more "ages" on this than you, and actually did some research of their own (indeed they wrote some of the boring documents you read!) rather than just regurgitating what they read on the 'net. If it comes down to which of you I believe, then I'm afraid the HPA (NRPB as was) have it...

 

Separately from that, you and many of these websites are calling on the HPA to prove that wifi is not dangerous, when it is quite hard to disprove a negative. I'm also not seeing much research offering any convincing proof that it is dangerous - even those pretty maps don't do much, as that is just 3 masts in the whole of the UK, so ignores all the others that presumably don't fit the model, and apparently disregards other causes of localised cancer pockets.

 

Rather morbidly, let's not forget that one-in-three people are going to get cancer, so finding a single isolatable root cause in that kind of volume is a near-impossible task. Many of them may be heavy users of mobile phones and/or wifi (of course, many of them won't be, either), but I suspect that many of them also eat bread, for example... (slightly poor analogy, but you see where I'm going...)

[farmerste]

thats cool, you need to weigh up the evidence for yourself and draw conclusions, i was wondering what the viewpoint was of parents, especially as it already seems to be fixed, by that i mean - 'anti mobile mast near school'

but not forgetting it would be interesting to find out what the rest think, especially parents/schools regarding power levels of wi-fi, after all we live in a democracy, and it would be good to offer , and verify ALL evidence presented, before we can make a balanced opinion.

Also rather than regurgitating, i think it is important that facts and figure can be summised, rather than reading loads of documents in detail, and that was what i was trying to do. I accept i can of misread/mis-understood the data present, but like i said i've tried my best to keep things accurate.

 

perhaps i just don't trust the government, after all it has not had a good record in that department, and it has always put money before people.

[SYNACK]

Just throwing in another few little chunks of information here. The WiFi signal is much closer to the frequencies used in a microwave and so it is more likely to be able to effectively transmit energy into the the body that could be absorbed.

 

Cell signals are far more powerful but also much further away from a frequency that can easily couple with human tissue. The other thing to take into account is that cellphones are regulated and so are controllable. If the same stuff were to happen with signals the strength of cellphone sites we would be in trouble as 20 cell sites on the same frequency would push out loads more energy than what is in use now.

[farmerste]

i was under the impression that wifi uses 2.4Ghz, same as microwave oven, and cell phones 900 mhz, and the lower frequency was 'worse' for the body?

[EeEk]

So far we have no wireless equipment, it’s been mentioned but has always been shot down in flames before it ever got to the point of frying little Johnny’s brains. Then again half the little Johnny’s here have so little brains a 10 seconds on defrost would be enough to finish them off.

 

What they purpose for here, part of the pathfinder project, is a microwave link from HQ then we feed 5 other council buildings.

 

When I spoke to the guy from THUS I asked how they planned to get it through planning once parents found out that’s its virtually a mobile phone mast on top of the school….his answer “hope no one notices and pays no attention or else there will be problems” Then he said….”is all a load of crap, it does you no harm, look at me, 40 years I’ve been doing this and I’m fine. When I worked for BT we used to climb into 4.8 meter dishes when they were powered up wearing radiation suits, it did me no harm”

 

Whether it did or not I don’t know, but the guy is 60+ ,has hair and sprinted up the stairs quicker than I did 

 

I would imagine there will be an uproar when this surfaces because that’s what folk do…its ok for little Johnny to have a mobile phone virtually in contact with his body 24hrs a day, sit in a wifi zone at night – maybe all day as well, get bombarded by SKY TV microwaves from a satellite, eat zapped food for his tea….but Oh no you cant put a mast there!!

 

Back to the CB thing…we all had ‘em before the internet/mobile phone age anyway my mate had one with a “rubber duck” aerial – a rubber aerial about 15” long bolted to a car wheel in his bedroom, he acquired a 500w booster for it which worked fine for a few weeks until it melted!! No exaggeration, it got so hot it bent over and moulded itself to the shape of the wheel….he then got an outside aerial but kept the booster….this is the same guy who had a modified mobile phone (first one I saw – brick size) modded for more power as we lived in the wilderness…now 30 years on and he’s cancer free.

[hotwired007]

i remember in my last job i was working on a Belkin pre-n router (108mb 3 antena) thing and i had that on my desk about 30 cm from me... from tuesday that week in the afternoon i was getting splitting headaches and going home...

 

i had a 35mile drive home and by the end of that the headache had cleared... the next week i moved the router to the otherside of the room and just used a long ethernet cable to work on it...

 

no headaches...

 

take whatever impression you want from that but i will always put waps way above head height and avoid working to close to them for a long time...

[SYNACK]

i was under the impression that wifi uses 2.4Ghz, same as microwave oven, and cell phones 900 mhz, and the lower frequency was 'worse' for the body?

 

It is not the same as a microwave oven, microwaves use a very specifically tunes frequency that couples with water and heats it up with very high efficiency.

 

WiFi does use microwaves but they are specifically tuned as far away from coupling with water as they can be so that people do not literally cook their legs when using a WiFi laptop (very slowly but surely). It is tuned as far away as it can be but it is still loosely coupled to water which is why things like people and trees kill WiFi signals very effectively as they are made of water and absorb more of the limited amount of energy.

 

Cellphones are even further away from coupling with water molecules and so pass through people and trees easier than WiFi even though they do still suffer loss.

[farmerste]

Thats good info, keep it coming, its always good to listen to others opinions.

But like i said i was trying to show when a WiFi point was working, the power emitted was equivalent to, someone situated at a point approximately 50m from a 10m high transmitter.

I realise that frequencies used are different etc, my main concern really is what would parents say if given all the evidence, both scientific, and circumstancial ( if it is ? ).

I know things like this can be a potential mine field, but leaukemia is higher when someone lives close to power lines, this has been studied, but i'm not sure if the findings have been scrutinised scientifically.

For instance lots of people go on pilgrimage to Lourdes in france believing that you can recieve a cure for ailments, but the actual recovery rate , is less than the average, its worse than if people had simply stayed at home.

there are still lots of questions, if we can have a 100mW WiFi station that can reach say 15 m with a good signal, why cant we simply buy a 200mw station that will do a 30 m radius?

 

as far as frequency is concerned, i think

the higher the frequency- the more like it is to cook, and not pass through

the lower the frequency - the more likely it is to penetrate, and pass through

 

not sure about about this though, what do you guys think?

[Jona]

But like i said i was trying to show when a WiFi point was working, the power emitted was equivalent to, someone situated at a point approximately 50m from a 10m high transmitter.

 

I can't help thinking the physics here is a bit flawed, unfortunatly I don't really have the time to prove it this morning.....

[webman]

i was under the impression that wifi uses 2.4Ghz, same as microwave oven, and cell phones 900 mhz, and the lower frequency was 'worse' for the body?

 

There are a range of frequencies used my mobile phones. See here and here

 

there are still lots of questions, if we can have a 100mW WiFi station that can reach say 15 m with a good signal, why cant we simply buy a 200mw station that will do a 30 m radius?

 

Bandwidth? Physical obstacles? Elevation? Your definition of 'station' is rather vague.

Edited May 9, 2008 by webman

[enjay]

I know things like this can be a potential mine field, but leaukemia is higher when someone lives close to power lines, this has been studied, but i'm not sure if the findings have been scrutinised scientifically.

 

This probably won't appease you much, but I think that the HPA have looked at this area too. A very brief search of their site doesn't turn any documents up, but that doesn't mean they're not there (especially since it was done pre-merger and there were therefore still the NRPB).

[farmerste]

Bandwidth? Physical obstacles? Elevation? Your definition of 'station' is rather vague.

 

By station, i mean wireless access point, ( sorry for me using common terms) but they come in a variety of shapes and sizes, some with aerials etc, and you can point the aerials in different directions to help with signals. so my point was, if the 100mW station is too weak, why not simply go and purchase a 200mW one? why is it restricted to 100mW

 

so for sake of argument, lets say a wireless access point out doors, when the signal degrades the further you are away from it, why cant you just get a better access point ? ( stronger signal- i.e more power ). using this idea building factors do not have to be taken into account.

[farmerste]

I can't help thinking the physics here is a bit flawed, unfortunatly I don't really have the time to prove it this morning.....

 

hi i have attached the doc that i found the reading of 100 wW from here

page 23 ( 29of64) in acrobat reader

[Jona]

Well isn't there a legal limit set by Ofcom for the power, otherwise it would potentially interfere with everything else in the 2.4ghz spectrum?

[Joanne]

thing is... so much stuff causes cancer these days; sun, food colouring, red meat, alcohol, smoking... if we were to try and avoid them all you'd just end up living in a bubble.

 

People will get cancer FACT

People will get cancer because of wifi... not so fact. You can't prove it unless you sit someone in a darkened room with an access point all their lives supping extra sanitised water and feeding them generic food....

 

Wifi probably contributes to cancer, but what doesn't these days?

[webman]

Ofcom - UK Frequency Allocation Table - shows just how crowded the 2.x GHz spectrum is.

 

Ofcom - UK Fixed Wireless Access, Wireless LAN and Wi-Fi frequency bands quotes the 100mW effective radiated power limit. 200mW and 1W is permitted in certain 5GHz band allocations (802.11a) and upto 2W for licenced users.

 

Without delving too far into radio theory and to stay within the context of the thread; radio signals will travel in a straight line from the antenna. Path loss caused by many factors (terrain - buildings, hills) is the reduction in power density. Upping the power may solve some problems but it is not guaranteed - that's the nature of radio waves. However, even if it did, and you were able to increase the amount of nodes you could reach - there are still a couple of issues to address. Antennas on the wireless nodes, are they directional or not?

 

I also mentioned bandwidth. Say your 100mW wireless 'station' has a 10meg connection to the internet, and you have 5 wireless nodes connecting to it. Then you increase your power to 200mW, potentially increasing the number of wireless nodes. You still have your 10meg connection which may or may not be enough to support all the nodes.

 

Ofcom - Understanding the Scope for a Power Increase for Wireless Broadband Access at 2.4GHz & 5.xGHz

 

Further reading

 

• Radio waves
  
• Radio propogation
  
• Radio propogation model
  
• Path loss

 

I'm a licensed radio ham so I have some understanding of the issues involved, but some of my knowledge is a bit rusty due to not being as active as other hams are. I'll take a computer keyboard over a radio mic any day

Edited May 9, 2008 by webman

[SimpleSi]

why cant you just get a better access point

 

Because the regulations in this (and many others) country have specified a maximum power that is well below any danger level that anyone is currently aware of.

 

The regulators do tests - they try and determine what effect certain levels of radiation at the frequencies involved have on various parts of the body (skin vs internal organs) and then when they find a detectable effect at a particular level - they then normally say OK - lets reduce the maximum allowed to 1000th of this level and we should be alright.

 

Sounds like a reasonable method to me

 

But then again, I'm at ex-RF transmission engineer and look what its done to me

 

regards

 

Simon

[SYNACK]

200mW one? why is it restricted to 100mW

 

so for sake of argument, lets say a wireless access point out doors, when the signal degrades the further you are away from it, why cant you just get a better access point ? ( stronger signal- i.e more power ). using this idea building factors do not have to be taken into account.

 

As netman said this only handles one side of the equation. Connectivity must go both ways, the laptop must be able to send back to the AP and so would also need to be increased in power putting the transmitter even closer. As laptops often have built in aerials that are not as good as a proper AP aerial it would need even more power to send information back to the AP.

 

Your method is a bit simplistic as it leaves out the difference that the frequencies make. It does not matter if the power at that distance works out the same because it is not absorbed at the same rate.

 

You could think of it like infra-red light, its just a small frequency change from visible light and yet you can see strait through a cup of coke with it as coke if almost transparent to IR. Same kind of thing with the wireless access, because of what people are made of they are more transparent to some frequencies (x-rays) than others wireless.

 

The stuff in my previous post is not circumstantial but based on my ammature radio training and stuff that I have read on the subject of wifi.

[farmerste]

here are a few more articles to read :-

 

Mobile And Wireless - Largest Biological Experiment - Health Supreme

 

http://www.emfacts.com/papers/dect.pdf

 

Report of the Independent Expert Group on Mobile Phones

 

http://www.iegmp.org.uk/documents/iegmp_4.pdf

 

http://www.scottish.parliament.uk/s3/committees/petitions/petitionsubmissions/sub-07/PE1048B.pdf

 

http://www.radiationresearch.org/Trustee_Eileen_OConnors_submission.pdf

 

Wi-Fi health risks are clouded by static - 15 May 2007 - IT Week

 

the above are in no specific order, and i have tried to give a balanced sample of reports.

i apologise for being away from this subject for a while, but i have been really busy, but my most recent finding/questions are :-

 

why can you buy a digital cordless home phone, that can emit greter power than a resticted wi-fi point?

 

and why are these so- called independant bodies, who perform investigations into dangers of mobiles/wifi etc have a short life span, is it just a funding issue ? or is money only given to the ones who give the required response?

 

why also do the above scientific bodies purely base their finding on thermal effects generated, and ignore all other health related data as just coincedence ??

 

why does the power measured at ground level from a mobile phone transmitter at certain points, not coincide with the theoretical power at those points ? ( in actual fact the measured amounts were much lower than what they should have been, but that only makes things worse when i am trying to compare the power outputs of mobile phone mast, to wi-fi point . the results mean you would be even closer to the emitter on the mast than thought previously)

 

i like this icon, maybe i'll be a vagrant like they have in the states with tinfoil on my head, when i have been made redundant by BSF

 

all feedback and viewpoints gratefully recieved

[enjay]

why are these so- called independant bodies, who perform investigations into dangers of mobiles/wifi etc have a short life span, is it just a funding issue ? or is money only given to the ones who give the required response?

 

Can't comment on all of them, but I know that for the likes of HPA it will be a funding question - they will have been given £x or a y-year grant. The people involved in those studies will now be working on something else.

 

Thanks for the links, I'll read through them when I have a chance (not sure when that will be though!).

[farmerste]

i have had another look at this, and i have found this recent document:-

 

http://www.powerwatch.org.uk/pdfs/20080425_wifi_memorandum.pdf

 

this documents backs up the findings in BBC's panorama programme last year, which caused an outcry ( of sorts ) and has an interesting illustration about power levels.

 

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the next document i found was sent to a school outlining concerns, and i think it is a very good document, that could be used to give a balanced view of the current situation :-

 

http://www.powerwatch.org.uk/pdfs/20070723_wifi_letter.pdf

 

much better than my attempt, IMHO

 

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take a look at this also :-

 

http://www.powerwatch.org.uk/pdfs/20061232_havas.pdf

 

[farmerste]

found a couple more interesting articles, the first is a radio show recording, so copy it to your mp3 player and have a listen, its about 1 hour long

 

http://www.buergerwelle.de/pdf/the_science_of_rfr_health_risks.mp3

 

**********

 

the next item is a document i found,

 

http://www.bioinitiative.org/report/docs/section_1.pdf

 

 

its got me scared now, does anyone know where you can buy foil hats??

 

lol