Health Concerns

GetOffMyPatch

Hi there,

I am contemplating installing a wireless router in my house.
The thing is that I have 2 young children and the missus has expressed concerns about having the signals floating round the house etc

Would appreciate any feedback/opinion/suggestions

Thanks

PS - This website is one of the best sites in the country - FACT!

Zynks

I have both... children and wlan at home. I must say those thoughts also crossed my mind, but at the end of the day you are exposed to this kind of transmission all the time with mobile phones (whether you have one or not), satellite transmission, electrical wiring, TV signals, microwave ovens, bluetooth, radio, DECT phones, and so on. There is no escaping them. Even in the most remote places on earth you will still get some of them, like satellite signal...

Bottom line, I don't know for sure, but if it was such an issue, I think wireless baby monitors would have been the prime target of concern since they are normally left all night long close beside babies.

But then, it took people a long time to find out the effects that asbestos would have...

Adeptus Titanicus

Hmmm, I was wondering about this as well, as my partner is pregnant and sits fairly close to my wireless access point. Needless to say, I haven't mentioned my concerns to her!

Zynks

Here are some links on the subject. They are rather inconclusive (there is no evidence of health risks so far...), although the second one says over 40 years of research has been carried out on the issue. One point of consensus is that Wlan offers far less risk than mobile phones:

http://searchnetworking.techtarget.com/originalContent/0,289142,sid7_gci937770,00.html

http://www.wlana.org/learn/health.htm

http://www.btplc.com/Societyandenvironment/Socialandenvironmentreport/Customers/Mobilephonesandhealth/Mobilecommunicationsandhealth.htm

http://www.ku.edu/acs/internet/wireless/wireless_faq.shtml

causal

GetOffMyPatch wrote:

I am contemplating installing a wireless router in my house.
The thing is that I have 2 young children and the missus has expressed concerns about having the signals floating round the house etc

imho, your missus is right to express concerns.
Personally I chose not to go wireless due to the risk of hazzardous effects of radiation. Yesterday I drilled through my upstairts floorboard and downstairs ceiling and routed a cat5 cable through to network with the PC downstairs.
No problemo.

There are 2 types of radiation of interest:
1) Ionising radiation - http://www.hse.gov.uk/radiation/ionising/
(x-rays, alpha, beta, gamma radiation)
2) Non-ionising radiation - http://www.hse.gov.uk/radiation/nonionising/
(UV, visible, infra-red light, EMFs - ElectroMagneticFields)

www.hse.gov.uk/radiation/nonionising wrote:

There are well-established short-term adverse health effects from excessive exposure to EMFs such as effects on the central nervous system and heating of the body.

EMF is what is of concern with wifi, mobile phones, dect phones etc.

There are probably 3 factors that determine the effect of radiation:
1) total time over which dose is absorbed
2) magnitude of the dose (strength of EMF)
3) part of body exposed

Now consider the following:
Mobile phone - operates at 900MHz / 1800MHz @ 2 / 1 W respectively (ref http://www.techmind.org/gsm/)
DECT phone - operates at 1880 to 1930 MHz @ 250mW max (ref below*)
802.11x (wifi) - operates at 2400MHz @ 100mW
Microwave oven - operates at about 2450MHz @ 600-900W

*see also:
http://www.dect.org/PDF/DF PUB(2004)002.0 DECT and Health, Fact and Figures.pdf
and
http://www.dect.org/PDF/DECT_Health_Brochure.pdf

So you can see that mobile phones, DECT phones, wifi, microwave ovens - are all in the microwave region of the EM spectrum. The only difference is the power of the signal i.e. the 'magnitude of the dose'.
Recall that the effect of radiation is determined by 3 factors.

So if you are sitting all day at a computer (also being irradiated by your monitor), plus your mobile phone, your dect phone, and your wifi equipment, well, you can draw your own conclusions.

Maybe you'd be really unlucky (allegedly) and live under power cables, and beside a mobile phone mast.
Now, lots of people are sceptical about the effects of EMR - but I doubt they'd volunteer to live with all the above all the time, and bring their kids along too.

And as for scientific reports being inconclusive and/or their findings disputed - that's par for the course with science; but (regretably) there is more and more often also business interest involved. I need only mention cigarettes and cancer, and the 'alleged' link between the two.

The legal profession long ago realised that little or nothing can be proven conclusively and they introduced concepts like 'reasonable doubt', 'preponderance of the evidence', and 'balance of probabilities'.
Mathematicians assigned probabilities between 0 and 1, exclusively iirc.
Philosophers have long debated what can be known.
Oops, now I am rambling...

Anyhow good luck with the network,
causAl
(now where's that damned Faraday cage?)

oscarBravo

causal wrote:

imho, your missus is right to express concerns.
Personally I chose not to go wireless due to the risk of hazzardous effects of radiation.

FUD, FUD, FUD.

causal wrote:

There are 2 types of radiation of interest:
1) Ionising radiation - http://www.hse.gov.uk/radiation/ionising/
(x-rays, alpha, beta, gamma radiation)

Not remotely relevant to a discussion on wireless networking.

causal wrote:

2) Non-ionising radiation - http://www.hse.gov.uk/radiation/nonionising/
(UV, visible, infra-red light, EMFs - ElectroMagneticFields)

www.hse.gov.uk/radiation/nonionising wrote:

There are well-established short-term adverse health effects from excessive exposure to EMFs such as effects on the central nervous system and heating of the body.

EMF is what is of concern with wifi, mobile phones, dect phones etc.

Correct, but you forgot to finish the quote:

These effects are prevented by compliance with guidelines published by the National Radiological Protection Board (NRPB). The NRPB has a statutory responsibility to provide scientific advice to government on radiation matters.

causal wrote:

There are probably 3 factors that determine the effect of radiation:

1) total time over which dose is absorbed
2) magnitude of the dose (strength of EMF)
3) part of body exposed

You're oversimplifying. What you describe as "magnitude of the dose" is determined by a number of factors: apart from the Tx power which you've mentioned, you have to take into account antenna gain and direction (if applicable) and distance from the antenna. The inverse square law means that the signal strength (and therefore the "magnitude of the dose") reduces with the square of the distance from the radiation source.

causal wrote:

Now consider the following:
Mobile phone - operates at 900MHz / 1800MHz @ 2 / 1 W respectively (ref http://www.techmind.org/gsm/)
DECT phone - operates at 1880 to 1930 MHz @ 250mW max (ref below*)
802.11x (wifi) - operates at 2400MHz @ 100mW
Microwave oven - operates at about 2450MHz @ 600-900W

[...]

So you can see that mobile phones, DECT phones, wifi, microwave ovens - are all in the microwave region of the EM spectrum. The only difference is the power of the signal i.e. the 'magnitude of the dose'.
Recall that the effect of radiation is determined by 3 factors.

So if you are sitting all day at a computer (also being irradiated by your monitor), plus your mobile phone, your dect phone, and your wifi equipment, well, you can draw your own conclusions.

You can, but will they be accurate?

If you're concerned about EMR, the first thing you'd better do is get rid of your mobile phone: 1-2W within a couple of cm of your brain is obviously a lot more hazardous than a 0.1W access point a few metres away.

causal wrote:

Maybe you'd be really unlucky (allegedly) and live under power cables, and beside a mobile phone mast.
Now, lots of people are sceptical about the effects of EMR - but I doubt they'd volunteer to live with all the above all the time, and bring their kids along too.

Lots of people do, which rather thoroughly refutes your point.

causal wrote:

And as for scientific reports being inconclusive and/or their findings disputed - that's par for the course with science; but (regretably) there is more and more often also business interest involved. I need only mention cigarettes and cancer, and the 'alleged' link between the two.

You need to mention a little more than that. What's your point? Do you reckong that the WiFi industry is suppressing evidence that 802.11b causes cancer?

bminish

oscarBravo wrote:

If you're concerned about EMR, the first thing you'd better do is get rid of your mobile phone: 1-2W within a couple of cm of your brain is obviously a lot more hazardous than a 0.1W access point a few metres away.

That's IF there are in fact any hazards associated with the use of mobile handsets, any effects found to date are subtle and hard to reproduce at the macro level.

.Brendan

Capt'n Midnight

At 2.4-2.5GHz
In EU WiFi is limited to 100mW EIRP , most cards are only 30mW
AFAIK microwave ovens are allowed to leak up to 1,000mW and still be legit.

In the US where people sue for big money over health concerns they are allowed much higher power limits on 2.4GHz - if there were concerns about safety they would have clamped down years ago.

Mobile phones can radiate up to a Watt in poor coverage areas and do it very close to your brain - frequency is a bit lower though.

You can get mobile phone detectors you know the things that light up when a phone rings - try one of them near your wifi / microwave to get a very rough ( it's not turned to those frewuencies ) idea of the power they radiate and how the inverse square law means that each time you double the distance from the device the RF dosage drops by a quarter.

causal

oscarBravo wrote:

FUD, FUD, FUD.

The only answer to that is to quote yourself:

oscarBravo wrote:

You need to mention a little more than that. What's your point?

oscarBravo wrote:

Not remotely relevant to a discussion on wireless networking.

It is at least 'remotely relevant' to the thread title which is 'Health Concerns'. And relevant to the broader picture of radiation and health.

oscarBravo wrote:

You're oversimplifying. What you describe as "magnitude of the dose" is determined by a number of factors: apart from the Tx power which you've mentioned, you have to take into account antenna gain and direction (if applicable) and distance from the antenna. The inverse square law means that the signal strength (and therefore the "magnitude of the dose") reduces with the square of the distance from the radiation source.

No. You're overcomplicating.
Perhaps you don't understand the word 'dose' in this context, it's a medical term, not an engineering term.
I did not mention 'Tx power', but I did say:
"magnitude of the dose (strength of EMF)"
- meaning the strength of EMF at the absorbtion site (the body) - perhaps you incorrectly assumed it meant at the Tx power at the transmitter.

Now I said "magnitude of the dose" - this is what is absorbed by the body - and yes it is determined by all of the factors you mentioned above, and others you didn't mention.

oscarBravo wrote:

causal wrote:

So if you are sitting all day at a computer (also being irradiated by your monitor), plus your mobile phone, your dect phone, and your wifi equipment, well, you can draw your own conclusions.

You can, but will they be accurate?

Well, there are 3 possible conclusions as I see it:
1) They have no effect on health.
2) They have negative effect on health.
3) They have positive effect on health.
My money is on 2. Which one do you put your money on?

oscarBravo wrote:

If you're concerned about EMR, the first thing you'd better do is get rid of your mobile phone: 1-2W within a couple of cm of your brain is obviously a lot more hazardous than a 0.1W access point a few metres away.

Agreed. And lots of people put their mobile phones in their trouser pockets - right beside their reproductive organs - most vulnerable due to the high rate of meiosis - and no thick skull for protection.

oscarBravo wrote:

causal wrote:

Maybe you'd be really unlucky (allegedly) and live under power cables, and beside a mobile phone mast.
Now, lots of people are sceptical about the effects of EMR - but I doubt they'd volunteer to live with all the above all the time, and bring their kids along too.

Lots of people do, which rather thoroughly refutes your point.

What evidence do you have that sceptics moved to areas with power cables and mobile phone masts?
Or are you asserting that because some people do live in such locations that they must have chose to do so because of the EMR, just to prove a point?
I doubt it, but if you have facts and figures then please let me know.
Some people live in sewers - not because they want to or because they think it's safe, but because of factors other than their long term health.

oscarBravo wrote:

causal wrote:

And as for scientific reports being inconclusive and/or their findings disputed - that's par for the course with science; but (regretably) there is more and more often also business interest involved. I need only mention cigarettes and cancer, and the 'alleged' link between the two.

You need to mention a little more than that. What's your point? Do you reckong that the WiFi industry is suppressing evidence that 802.11b causes cancer?

I don't intend to libel myself. But you can ask yourself these questions:

1) Is it not the case that there is precedent for corporations to deliberately suppress information indicating that their product was harmful to humans?

2) Is it not the case that there is precedent for corporations to unknowingly supply products that were harmful to humans?

3) Is it not the case that there is precedent for corporate sponsored research to be biased towards the interest of the corporate sponsor?


causAl

bminish

causal wrote:

The only answer to that is to quote yourself:

Well, there are 3 possible conclusions as I see it:
1) They have no effect on health.
2) They have negative effect on health.
3) They have positive effect on health.
My money is on 2. Which one do you put your money on?

My money is on 1 as is all currently accepted scientific evidence.

there is a certain amount of pseudo-scientific 'research' doing the rounds but many of the most outspoken pseudo-scientists (Roger Coghill being a particularly well known one ) have a definite vested interest in convincing us that E/M exposure at current levels is harmful, in Coghill's case he makes lots of money from Selling and endorsing products to protect us from this 'risk' as well as doing the lecture circuit speaking against masts etc to the anti lobby.

Agreed. And lots of people put their mobile phones in their trouser pockets - right beside their reproductive organs - most vulnerable due to the high rate of meiosis - and no thick skull for protection.

Where in most cases the phone is in standby and only transmits the occasional pulse to remain in contact with the base station. Still I suppose some users may be talking though their arse

What evidence do you have that sceptics moved to areas with power cables and mobile phone masts?

One of the funny things is that the anti-power-line lobby want them placed under ground, this places people much closer to the line. Illogical argument don't you think!

I don't intend to libel myself. But you can ask yourself these questions:

1) Is it not the case that there is precedent for corporations to deliberately suppress information indicating that their product was harmful to humans?

2) Is it not the case that there is precedent for corporations to unknowingly supply products that were harmful to humans?

3) Is it not the case that there is precedent for corporate sponsored research to be biased towards the interest of the corporate sponsor?
causAl

It is also the case that the vast majority of the 'E/M' radiation is dangerous ' 'research' is produced by people with vested interests in products that 'protect' us from this 'risk.'
Let's stick to proper peer reviewed science please, people have been studying the effects of E/M radiation on humans for a very long time, People have been working with and exposed to microwave radiation since the 40's.
Where are all the dead radar, TV & radio technicians ?
Where are the large pockets of strange cancers ?

I was reading a book about the early history of the Marconi Corporation and came across these couple of paragraphs, FUD about radio waves has been around since the beginning of radio. Some things never change

In the spring of 1899 the French government gave permission to erect a mast for experimental purposes at Wimereux, near Boulogne, and a corresponding mast was erected at the South Foreland Lighthouse, near Dover.

The stations were completed in March, and Marconi transmitted messages across the Channel for the first time on 27th March 1899. The successful result created immense and universal public interest, and the importance to the shipping interests was generally accepted. Letters were received from all over the world, Some asking for information, some giving advice, and many from cranks and madmen who attributed the illnesses from which they suffered to the passing of the wireless waves though their bodies.

An amusing case occurred at Wimereux , which if it had not been for the tact of the Engineer-in-charge , Mr W. W. Bradfield, might have been a tragedy. A man burst into the wireless room brandishing a revolver and stating that the wireless waves gave him intense internal pains and unless the engineer stopped the apparatus he would shoot him. Mr Bradfield at once expressed his sympathy , and told him he had heard of other people who had been similarly inconvenienced but he had come to the right man to cure him and all that was necessary was a form of electrical inoculation. If he would consent to receive a shock from the aerial he would be immune from the effect of electric waves for ever after , but he must first put aside any metal coins he might have in his pocket and, of course, a large piece of metal like the revolver. The man at once agreed , he was given a very severe shock but went away happy and contented.

Extract from: Marconi and Wireless by R.N. Vyvyan
ISBN 0 7158 1050 2
First Published 1933 as Wireless over thirty years

.Brendan

causal

bminish wrote:

causal wrote:

1) They have no effect on health

My money is on 1 as is all currently accepted scientific evidence.

Well I don't claim to have read all of the currently accepted scientific evidence. Do you?
Does all this 'accepted' research totally dismiss the possibility of a negative effect on health from EMR?

"Currently accepted" is precisely right; Science has got it wrong in the past, is doing so in the present, and will do so in the future. That's the nature of discovery and invention. Some people have blind faith in science, but I think Neils Bohr understood things better:
As Einstein said of Bohr:

He utters his opinions like one perpetually groping and never like one who believes he is in possession of definite truth.

bminish wrote:

there is a certain amount of pseudo-scientific 'research' doing the rounds but many of the most outspoken pseudo-scientists (Roger Coghill being a particularly well known one ) have a definite vested interest in convincing us that E/M exposure at current levels is harmful, in Coghill's case he makes lots of money from Selling and endorsing products to protect us from this 'risk' as well as doing the lecture circuit speaking against masts etc to the anti lobby.

But it's the same for companies who "have a definite vested interest in convincing us that E/M exposure at current levels is" _not_ "harmful".
In itself it doesn't mean they're wrong or right in what they say.
It seems there is bias in research interpretation on both sides, after all, _both sides_ have vested interests.

bminish wrote:

causal wrote:

Agreed. And lots of people put their mobile phones in their trouser pockets - right beside their reproductive organs - most vulnerable due to the high rate of meiosis - and no thick skull for protection.

Where in most cases the phone is in standby and only transmits the occasional pulse to remain in contact with the base station. Still I suppose some users may be talking though their arse

Huh! Well I dunno where you stick your phone :eek: But when I said trouser pocket I meant trouser pocket.
How occasional the transmissions from your phone are depends on your movement between cells. Going from say the top of Grafton Street to O'Connell St you'd be handed over several times. And if your phone is beside your gonads for hours day in day out it adds up.

bminish wrote:

One of the funny things is that the anti-power-line lobby want them placed under ground, this places people much closer to the line. Illogical argument don't you think!

That depends on how it's implemented and whether the cables are located near residential areas. As oscar_bravo pointed out the inverse-square law is only one factor. UG cables are much better insualted than OH, plus the permitivity of soil and rock is much lower than that of air for EM fields. If the cables are properly shielded then the EM field outside the cable should be zero/minimal.

bminish wrote:

It is also the case that the vast majority of the 'E/M' radiation is dangerous ' 'research' is produced by people with vested interests in products that 'protect' us from this 'risk.'
Let's stick to proper peer reviewed science please, people have been studying the effects of E/M radiation on humans for a very long time, People have been working with and exposed to microwave radiation since the 40's.
Where are all the dead radar, TV & radio technicians ?
Where are the large pockets of strange cancers ?

Both sides of that argument are making a living from their activities.

iirc cancer is the second biggest killer on the planet, after heart disease.
Something causes cancer, unless it just happens for no reason.

Do you have zero belief in the 'E/M' radiation is dangerous ' brigade, and full belief in the 'E/M' radiation is not dangerous ' brigade?

bminish wrote:

I was reading a book about the early history of the Marconi Corporation and came across these couple of paragraphs, FUD about radio waves has been around since the beginning of radio. Some things never change

Yeah all types of FUD fly around from both sides.
The Marconi story tells us what in your opinion? Is it that anyone who thinks EMR may be harmful is a gun wielding madman in need of electric shock treatment :rolleyes:

Your language appears to differ depending on which of the two sides in this debate you refer to:

EMR is Dangerous - you say:
pseudo-scientific 'research'
pseudo-scientists
definite vested interest
makes lots of money
Illogical argument
FUD about radio waves
& an anecdote about a deranged man with a gun

EMR isn't Dangerous - you say:
accepted scientific evidence
stick to proper peer reviewed science

bminish wrote:

In the spring of 1899 ...

Isn't it ironic that this is the same time that a highly intelligent and well respected scientist, indeed a great physicist who four years later (1903) won the Nobel Prize in Physics (study of spontaneous radiation), and eight years after that (1911) won the Nobel prize in Chemistry (for her work in radioactivity), was unknowingly irradiating herself with radium.

The nutter with the gun may have been wrong about the EMR, but Marie Curie was wrong about radium.

So maybe you were right when you said "Some things never change".


causAl

oscarBravo

causal wrote:

It is at least 'remotely relevant' to the thread title which is 'Health Concerns'. And relevant to the broader picture of radiation and health.

I could talk about smoking and saturated fat, and still be relevant to the thread title. The actual subject under discussion is the safety of WiFi, which does not generate ionising radiation.

causal wrote:

No. You're overcomplicating.
Perhaps you don't understand the word 'dose' in this context, it's a medical term, not an engineering term.
I did not mention 'Tx power', but I did say:
"magnitude of the dose (strength of EMF)"
- meaning the strength of EMF at the absorbtion site (the body) - perhaps you incorrectly assumed it meant at the Tx power at the transmitter.

Now I said "magnitude of the dose" - this is what is absorbed by the body - and yes it is determined by all of the factors you mentioned above, and others you didn't mention.

Allow me to quote you directly:

The only difference is the power of the signal i.e. the 'magnitude of the dose'.

In other words, you directly implied that the Tx power is the only factor that affects the exposure levels.

causal wrote:

Well, there are 3 possible conclusions as I see it:
1) They have no effect on health.
2) They have negative effect on health.
3) They have positive effect on health.
My money is on 2. Which one do you put your money on?

If you're going to round off to whole numbers, then 1, obviously.

causal wrote:

Agreed. And lots of people put their mobile phones in their trouser pockets - right beside their reproductive organs - most vulnerable due to the high rate of meiosis - and no thick skull for protection.

And, funnily enough, there hasn't been a surge in reported cases of gonads falling off.

causal wrote:

What evidence do you have that sceptics moved to areas with power cables and mobile phone masts?
Or are you asserting that because some people do live in such locations that they must have chose to do so because of the EMR, just to prove a point?

You're good at the straw man thing, aren't you? You didn't ask any questions about moving, and you didn't ask me about the reasons for why people live where they do. The question I was answering was whether people choose to live in those environments, and allow their children to live there. The fact is, lots of people live in such environments, and choose to continue living there, and are not remotely bothered by the possibility of health risks from EMR. Your sewer analogy paints a picture of desperate families forced by harsh circumstances to endure the agony of living near electric power cables, but I somehow doubt many of them see it that way.

oscarBravo

causal wrote:

But it's the same for companies who "have a definite vested interest in convincing us that E/M exposure at current levels is" _not_ "harmful".
In itself it doesn't mean they're wrong or right in what they say.
It seems there is bias in research interpretation on both sides, after all, _both sides_ have vested interests.

Are you suggesting that the NRPB has some sort of vested commercial interest in convincing us that we're not at risk from EMR?

causal wrote:

Isn't it ironic that this is the same time that a highly intelligent and well respected scientist, indeed a great physicist who four years later (1903) won the Nobel Prize in Physics (study of spontaneous radiation), and eight years after that (1911) won the Nobel prize in Chemistry (for her work in radioactivity), was unknowingly irradiating herself with radium.

Do you have any smoke detectors in your house?

Kernel

I was also worried about the effects of a wireless network before I installed my own one, so I did some research at the time.. most of the details have been lost from memory, but in the end, there is no evidence to suggest that radio waves cause any health problems whatsoever. Think about the waves flying About all over the place, from 98FM and such radio stations. Radio waves also occur naturally in the universe, and the earth is constantly being blasted with cosmic radio waves from space. The waves pass through your body (and the earth) without any effect.

There was some research that was carried out by the US government, over 40 years (apparently one of the most researched health studies ever), to check any effects of radio waves, and nothing was found. If you were living next door to the 98FM studio, you wouldn't be worried, even though the strength of the radio waves are many thousands that of a typical wireless lan. Likewise if you are living near a Garda station. Do you have a cordless telephone? That uses the same technology - and even on the same 2.4ghz frequency.

Bottom line is, I personally think that they are safe, whether radio waves can subtly affect the brain, or give you a migraine, is another thing, but I sure don't think that they can cause lasting damage (cancer etc), as some reaserch has shown microwaves (which are different to radio waves) can do.

People once thought asbestos was safe, and lead was a great thing to have in petrol, but I'd like to think that there is more stringent health testing done nowadays - if not for humanitarian reasons then just to protect from big lawsuits!

Gone West

the fundamental frequency of water is 2.450ghz give or take a few mhz, depending on the liquid. This is the principal of a microwave oven, to emit electromag waves on it and therefore vibrate water molecules and therefore make them heat up by friction. as you know the human brain is made up partly of water/ water- based substances. It is quite possible, (althgough not yet verified) that some of the substances in the human body may have a fundamental frequency of 2.4 ghz or similar. Perhaps our wireless lans are acting like low wattage microware ovens on our bodies? Forgive the rant/incomprehendible words.

causal

oscarBravo wrote:

Allow me to quote you directly:

Quote:
The only difference is the power of the signal i.e. the 'magnitude of the dose'.

In other words, you directly implied that the Tx power is the only factor that affects the exposure levels

No. And you're quoting that totally out of context. That sentence forms part of a paragraph from another part of my post. This part:

So you can see that mobile phones, DECT phones, wifi, microwave ovens - are all in the microwave region of the EM spectrum. The only difference is the power of the signal i.e. the 'magnitude of the dose'.
Recall that the effect of radiation is determined by 3 factors.

And you will notice that I _specifically_ reiterated that the "effect of radiation is determined by 3 factors"
So you are erroneous in saying say that I "directly implied that the Tx power is the only factor that affects the exposure levels".

oscarBravo wrote:

And, funnily enough, there hasn't been a surge in reported cases of gonads falling off.

Interesting.
Do you have statistics, or a literature reference to support this assertion?

oscarBravo wrote:

You're good at the straw man thing, aren't you? You didn't ask any questions about moving, and you didn't ask me about the reasons for why people live where they do.

Am I interviewing President Bush? Do you want to furnish me with the questions you think I should be asking you :rolleyes:
If you want to say something you can say it, if I want to ask something I can ask it - and vice versa.

oscarBravo wrote:

The question I was answering was whether people choose to live in those environments, and allow their children to live there. The fact is, lots of people live in such environments, and choose to continue living there, and are not remotely bothered by the possibility of health risks from EMR.

There's no question that lots of 'people' do live in such situations, but the people I was talking about were the 'people who were sceptical' about the hazzardous effects of EMR - I was asserting that I doubt droves of them would 'move' near to power lines and mobile phone masts and bring their children just to try to prove the point. Fair enough I wouldn't really expect them to do so.

But I'd be interested to see if the sceptics would object to planning permission for powerlines overhead and mobile phone masts beside their own house.

oscarBravo wrote:

Your sewer analogy paints a picture of desperate families forced by harsh circumstances to endure the agony of living near electric power cables, but I somehow doubt many of them see it that way.

I wouldn't buy a house with power cables overhead, or a phone mast beside it.
In all honesty, would you?

causAl

causal

oscarBravo wrote:

Are you suggesting that the NRPB has some sort of vested commercial interest in convincing us that we're not at risk from EMR?

No. And it's a big leap on your part to conceive that I may have been making that suggestion.

I said "companies" - the NRPB are not a company, they're a Government appointed body. They don't profit one way or the other, they have no vested interest nor do they have any commercial interest (notwithstanding any individual agenda that an appointed member may have).

oscarBravo wrote:

Do you have any smoke detectors in your house?

Yes, but I disabled them because my cigarette smoke kept setting them off , especially the one in the bedroom beside my oxygen tank

causAl

bminish

causal wrote:

But I'd be interested to see if the sceptics would object to planning permission for powerlines overhead and mobile phone masts beside their own house.

I already have powerlines beside my house, most of us in rural one off housing do, thats why the lights work
BTW the underground argument posted earlier is bunk, insulation is not relevant to the E and M fields. the relative permittivity of soil is between 2.5 and 3.5 so one still needs to go deep (as in 20m + deep for 220Kv lines) to keep the field strength equal or less than that of overhead lines, perhaps it's a case of out of sight out of mind?

underground lines cost lots more, why should my already expensive electricity cost even more to satisfy other's unfounded fears?
Power Lines and Cancer FAQ

If someone would put a mobile mast near my house I would probably become their customer, I have a poor signal down this neck of the woods. Phone masts are completely safe, as in no risk whatsoever.
Mobile Phone (Cell Phone) Base Stations and Human Health

I understand RF, I am completely satisfied that there are no health risks whatsoever with masts. Perhaps you think the current exposure limits are too high (I don't ) but perhaps you do?

Have a look at some site reports, mast sites come in, when measured by independent audit many thousands of times below these limits. See comreg's NIR section for site reports of Irish RF installations including many Mobile masts

There is no credible evidence to suggest that there are any cumulative effects of E/M radiation (since is is non-ionising) therefore long term expose to levels that are thousands of times below the already quite low limits is a good margin in anyone's terms and it would be nice to live some place where my mobile worked anywhere in the house

I wouldn't buy a house with power cables overhead, or a phone mast beside it.
In all honesty, would you?

Yes, and I would get it at a better price because of all the muppets with irrational phobias that would not be competing with me on the purchase price

.Brendan

causal

bminish wrote:

BTW the underground argument posted earlier is bunk, insulation is not relevant to the E and M fields. the relative permittivity of soil is between 2.5 and 3.5 so one still needs to go deep (as in 20m + deep for 220Kv lines) to keep the field strength equal or less than that of overhead lines, perhaps it's a case of out of sight out of mind?

You're wrong. Like I already said "If the cables are properly shielded then the EM field outside the cable should be zero/minimal."
Check out the Faraday Cage:
http://webphysics.davidson.edu/Applets/Poisson/Faraday.html

bminish wrote:

underground lines cost lots more, why should my already expensive electricity cost even more to satisfy other's unfounded fears?
Power Lines and Cancer FAQ

Unfounded? The studies listed in the faq are not unanimous.
I acknowledge that the _majority_ of studies find that there is little or no proven causal link between normal exposure levels and cancer.
But I don't blindly accept that as a fact which is true for all cases forever.
Some studies have indicated a link, and some have found that there are certain groups who have a higher risk profile - namely children.

bminish wrote:

Phone masts are completely safe, as in no risk whatsoever.
Mobile Phone (Cell Phone) Base Stations and Human Health

This part of that faq is priceless:

Are scientists seriously concerned about possible health risks from mobile phone base station antennas?
Not really. <snip>

Patient: "So Doctor, do I have cancer?"
Doctor: "Not really"

And the same faq says:

The possibility therefore remains open that there could be health effects from exposure to RF fields below guideline levels; hence continued research is needed."

I'm glad to see the Stewart Comission (from the same faq about phone masts) use proper scientific caveats like "balance of evidence indicates", "overall evidence indicates ", "biological evidence suggests ".
- those guys talk like scientists should.

bminish wrote:

I understand RF, I am completely satisfied that there are no health risks whatsoever with masts. Perhaps you think the current exposure limits are too high (I don't ) but perhaps you do?

Maybe you do understand RF, maybe you even understand the physiological effecs too. You certainly seem to be more confident about the health risks than the Stewart Commision. But unless you're omniscient perhaps you should consider keeping an open mind.

As for exposure levels. How do I know for sure, they seem plausible - I certainly don't expect my head to melt off :eek:
I know that my exposure is a lot less than people living next door to masts or under power lines, sitting beside wireless routers and DECT phones and mobile phones - I think that puts them at greater risk than me. Is their risk below the threshold for causal negative effects - I don't know, I just choose not to expose myself to the higher risk.

bminish wrote:

There is no credible evidence to suggest that there are any cumulative effects of E/M radiation (since is is non-ionising) therefore long term expose to levels that are thousands of times below the already quite low limits is a good margin in anyone's terms and it would be nice to live some place where my mobile worked anywhere in the house

"No credible evidence" you say!
So the studies that did indicate a link are not credible, whereas studies that did not indicate a link are credible.
Is that based on some logic like 'the majority finding is in fact true for all cases, and the minority finding is dismissed'?

Also, there are well established links between non-ionising radiation and tissue damage caused by heating. This _shouldn't_ happen at recommended exposure levels, but the usual caveats apply.

bminish wrote:

Yes, and I would get it at a better price because of all the muppets with irrational phobias that would not be competing with me on the purchase price

Let's score your post on the pejorative-ometer :rolleyes: today we had:
bunk
unfounded fears
no credible evidence
muppets with irrational phobias

That's a score of 4.5 - last time it was 7.

And good luck with the house if you go for it

causAl

bminish

causal wrote:

You're wrong. Like I already said "If the cables are properly shielded then the EM field outside the cable should be zero/minimal."
Check out the Faraday Cage:
http://webphysics.davidson.edu/Applets/Poisson/Faraday.html

Yes BUT they are usually not shielded although some are coaxial and even this would do nothing about the magnetic field which is what most of the FUD is about!

Unfounded? The studies listed in the faq are not unanimous.
I acknowledge that the _majority_ of studies find that there is little or no proven causal link between normal exposure levels and cancer.
But I don't blindly accept that as a fact which is true for all cases forever.
Some studies have indicated a link, and some have found that there are certain groups who have a higher risk profile - namely children.

Where is the quote from?



But the focus is on handsets which get pretty close to the current limits due to proximity to the head, not masts that are many thousands of times below these limits due to inverse square law or low powered (as in >100mW EIRP) WiFi equipment

http://www.mcw.edu/gcrc/cop/cell-phone-health-FAQ/toc.html#9

I'm glad to see the Stewart Comission (from the same faq about phone masts) use proper scientific caveats like "balance of evidence indicates", "overall evidence indicates ", "biological evidence suggests ".
- those guys talk like scientists should.

Yes of course they do, one can never prove something is safe, science is like that.

Maybe you do understand RF, maybe you even understand the physiological effecs too. You certainly seem to be more confident about the health risks than the Stewart Commision

is this the same commission whose report says

"The biological evidence suggests that RF fields do not cause mutation or initiate or promote tumour formation, and the epidemiological data overall do not suggest causal associations between exposures to RF fields, in particular from mobile phone use, and the risk of cancer"

There is however some concern in relation to handsets due to proximity (I.e exposure levels) but there are no proven links and no proven biological mechanisms that could case effects at these power levels. However since exposure levels base stations are many thousands of times lower than the limits (as are the exposure levels from a WiFi AP a couple of feet away )
I think it is reasonable to say that there no credible risk associated with either Cell phone masts or WiFi Equipment.

. But unless you're omniscient perhaps you should consider keeping an open mind.

Like yourself?

As for exposure levels. How do I know for sure, they seem plausible - I certainly don't expect my head to melt off :eek:
I know that my exposure is a lot less than people living next door to masts or under power lines, sitting beside wireless routers and DECT phones and mobile phones - I think that puts them at greater risk than me.

I don't agree.

We are not dealing with ionising radiation where even one gamma photon can, if you are extremely unlucky cause the DNA damage that gave you cancer.

With E/M radiation we have thermal effects which have a threshold level (below which they have no effect). there is also the remote possibility of non-thermal effects, there are a lot of ongoing studies on this, these studies are all carrying out experiments at the upper limits of the permitted exposure levels (makes it easer to see any effects ) so far they have found nothing that is in any way conclusive.

I would be willing to consider a margin of thousands of times below current limits (limits at which, remember there are no conclusive effects ) and call it perfectly safe, but ultimately it's up to you.

"No credible evidence" you say!
So the studies that did indicate a link are not credible

show me some that stand up to peer review !

Also, there are well established links between non-ionising radiation and tissue damage caused by heating. This _shouldn't_ happen at recommended exposure levels, but the usual caveats apply.

measurable heating effects don't occur at recommended levels, that's how they were decided upon many years ago, no measurable heating effects with an additional safety factor

Let's score your post on the pejorative-ometer :rolleyes: today we had:
bunk
unfounded fears
no credible evidence
muppets with irrational phobias

Ahh, We have a master of the misquote

I stand by that lot, including the Muppet statement

.Brendan

oscarBravo

causal wrote:

But I'd be interested to see if the sceptics would object to planning permission for powerlines overhead and mobile phone masts beside their own house.

I would have no issue with a mobile phone mast near my house, and I already have powerlines nearby.

causal wrote:

I wouldn't buy a house with power cables overhead, or a phone mast beside it.
In all honesty, would you?

Neither would be a negative factor for me, no.

causal wrote:

Yes, but I disabled them because my cigarette smoke kept setting them off , especially the one in the bedroom beside my oxygen tank

It was a genuine question, with a specific point: most domestic smoke detectors contain an ionising radiation source (usually Americium). So, do you have any?

causal

bminish wrote:

Yes BUT they are usually not shielded although some are coaxial and even this would do nothing about the magnetic field which is what most of the FUD is about!

You're wrong again!
Let's recap on the previous posts on this particular point:
You said that the anti powerline lobby want cables underground and asked if it was illogical
I said it depended on how it was implemented - how close to residential areas, and if the cables are properly shielded there should be no/minimal EM field
You said that was bunk.
I said you were wrong, and posted the link to the Faraday cage illustrating my point.
You said that does nothing for the magnetic field which was what the FUD is about
Now I'm saying your wrong again and have posted another link below illustrating my point.

from http://www.emishieldinggaskets.com/faraday_cage%20_tent.htm
"Mu-copper foil is used in shielded rooms, shielded chambers and faraday cages and has high damping properties in the electrical field (up to 120dB) as well as in the magnetic field (see table)."

bminish wrote:

causal wrote:

Some studies have indicated a link, and some have found that there are certain groups who have a higher risk profile - namely children.

Where is the quote from?

Here: http://www.emrnetwork.org/schools/maisch_3_03.pdf

bminish wrote:

causal wrote:

I'm glad to see the Stewart Comission (from the same faq about phone masts) use proper scientific caveats like "balance of evidence indicates", "overall evidence indicates ", "biological evidence suggests ".
- those guys talk like scientists should.

Yes of course they do, one can never prove something is safe, science is like that.

Well well well. Finally.
Is it fair to conclude that you acknowledge that wifi routers, DECT phones, mobile phones, powerlines can't be proven to be safe?
That was my whole premise from the beginning. Recall my statement:

And as for scientific reports being inconclusive and/or their findings disputed - that's par for the course with science;

bminish wrote:

causal wrote:

You certainly seem to be more confident about the health risks than the Stewart Commision

is this the same commission whose report says

"The biological evidence suggests that RF fields do not cause mutation or initiate or promote tumour formation, and the epidemiological data overall do not suggest causal associations between exposures to RF fields, in particular from mobile phone use, and the risk of cancer"

Now you're getting it. This reiterates my point above about science being inconclusive, it also reiterates another point I made to you in a previous post:

causal wrote:

"Currently accepted" is precisely right; Science has got it wrong in the past, is doing so in the present, and will do so in the future. That's the nature of discovery and invention.

bminish wrote:

I think it is reasonable to say that there no credible risk associated with either Cell phone masts or WiFi Equipment.

I think in practice we probably only differ slightly on this.
Firstly: I tend to use the concept of 'probability' rather than the word 'credibility'. It's more than mere semantics.
Secondly: I likely assign the _risk_ a higher probability than you do.
Thirdly, we may have different risk thresholds on this issue.

bminish wrote:

causal wrote:

. But unless you're omniscient perhaps you should consider keeping an open mind.

Like yourself?

Absolutely. I do have an open mind on the issue. Read back through my posts and I'm sure you'll find that I treat all findings as such. Remember Einsteins quote about Bohr.
You were the one who made the assertions about absolute safety etc. If, by the same token, someone posted with similar certainty that there was an absolute proven danger, then I would equally question ther assertions.
Question everything and keep an open mind.

bminish wrote:

causal wrote:

As for exposure levels. How do I know for sure, they seem plausible - I certainly don't expect my head to melt off
I know that my exposure is a lot less than people living next door to masts or under power lines, sitting beside wireless routers and DECT phones and mobile phones - I think that puts them at greater risk than me.

I don't agree.

Your disagreement contradicts your own statement that science can't prove something is safe:
You stated that science can't prove these items are safe, therefore there is a _risk_ by being exposed to them
It's logical to conclude that greater exposure proports to a greater risk (unless you think there is a either an inverse relationship between exposure and risk, or no relationship at all)

bminish wrote:

I would be willing to consider a margin of thousands of times below current limits (limits at which, remember there are no conclusive effects ) and call it perfectly safe, but ultimately it's up to you.

That's fair enough if it's your opinion. If you were to state it as an absolute fact - that would be different.

bminish wrote:

Ahh, We have a master of the misquote

Really! Where did I misquote you?



causAl

causal

oscarBravo wrote:

I would have no issue with a mobile phone mast near my house, and I already have powerlines nearby. Neither would be a negative factor for me, no.

Fair enough.
Is it fair to say that:
In 'theory' we differ on the perceived risk level, and again possibly on our risk threshold.
In practice we differ because I consider the above as negatives, but you don't.

Whatever the case, I maintain an open mind on this issue. In my opinion I'm playing it safe. Some will say too safe - others will say too risky.

oscarBravo wrote:

It was a genuine question, with a specific point: most domestic smoke detectors contain an ionising radiation source (usually Americium). So, do you have any?

Sure. Yes I have four smoke detectors. Two in operation and two backup.


By the way I came across this site which should give you a good laugh, I certainly enjoyed it
http://www.lessemf.com/personal.html


causAl

aidan_walsh

causal wrote:

Is it fair to conclude that you acknowledge that wifi routers, DECT phones, mobile phones, powerlines can't be proven to be safe?

Is it fair to conclude that you acknowledge that wifi routers, DECT phones, mobile phones, powerlines can't be proven to be unsafe?

bminish

causal wrote:

You're wrong again!

Now I'm saying your wrong again and have posted another link below illustrating my point.

The Faraday shield does not do anything about the magnetic field, to demonstrate try the following experiment

wrap thoroughly your mobile in aluminium foil, now call it. it will be out of coverage if you did a good enough job on the wrapping

Now wrap one steel nut in foil, pick it up with a magnet, since you can pick it up you have just demonstrated that a Faraday shield has no effect on the magnetic field for that you need magnetic shielding such as MuMetal.

Mu Metal (Which I have used to shield Oscilloscope CRT tubes in close proximity to PSU transformers) Is extremely expensive, has it's magnetic shielding properties damaged by heat, bending, mishandling and has quite a low magnetic saturation point . it's a specialist material that is only used for specialist applications such as your link suggests.

A shield such as this could not be used around underground power lines, do you understand how a transformer works by coupling into the near magnetic field of a conductor carrying AC? Good.
Now you will understand why effective magnetic shielding of HT lines is not as a rule done, underground or overground.

Well well well. Finally.
Is it fair to conclude that you acknowledge that wifi routers, DECT phones, mobile phones, powerlines can't be proven to be safe?
That was my whole premise from the beginning. Recall my statement:

Round in circles we go again, There is no evidence of risk either, even at mobile phone handset type exposure levels which are orders of a magnitudes larger (mainly due to proximity to the user) than exposure from WiFi, Mobile base stations or DECT base stations.

Your disagreement contradicts your own statement that science can't prove something is safe:
You stated that science can't prove these items are safe, therefore there is a _risk_ by being exposed to them

NO! Just because something isn't proven to be safe does not mean that it is correct to assume that it is dangerous.

It's logical to conclude that greater exposure proports to a greater risk (unless you think there is a either an inverse relationship between exposure and risk, or no relationship at all)

Even IF there is risk at current exposure level limits it is not very likely that there is risk at all lower levels, Radio-wave and microwave photons simply don't have the energy to do non-thermal damage. Microwave photons are far more feeble that light photons which are in turn far more feeble than X-ray or gamma Photons

if low level exposure to microwaves is dangerous then it's logical also to conclude that low level exposure to light (& I DO mean low*) is also harmful

* If a 100mW WiFi base station was instead replaced by a conventional torchbulb with 5% visible efficiency (the other 95% is mostly radiated as Infra red photons) one would need to power that bulb with 2w for 100mW of the applied power to be radiated as visible E/M radiation. Not very bright a couple of metres away is it?

Really! Where did I misquote you?

I don't think you have misquoted me but you have played fast and loose with the various reports etc you have been quoting.

.Brendan

oscarBravo

causal wrote:

Is it fair to say that:
In 'theory' we differ on the perceived risk level, and again possibly on our risk threshold.
In practice we differ because I consider the above as negatives, but you don't.

I don't think it's about risk thresholds, per se. I'm actually quite risk-averse: I don't tend to participate in dangerous activities if I can avoid them. Your avoidance of WiFi seems to me to be on a par with refusing to leave your house because of the risk of being hit by a meteorite.

causal wrote:

Whatever the case, I maintain an open mind on this issue. In my opinion I'm playing it safe. Some will say too safe - others will say too risky.

The preponderance of evidence is that, on balance of probability, there is no risk from EMR. That's good enough for me.

causal wrote:

Sure. Yes I have four smoke detectors. Two in operation and two backup.

I thought you might. Don't you think you're being inconsistent by having them? After all, you've pointed out yourself the fact that ionising radiation has been clearly demonstrated to cause health problems. How can you justify having four active sources of ionising radiation in your house?

causal wrote:

By the way I came across this site which should give you a good laugh, I certainly enjoyed it
http://www.lessemf.com/personal.html

I've seen it before, actually. What's funny is that a homemade tinfoil hat will provide the same health benefits at a fraction of the cost.

Kernel

oscarBravo wrote:

What's funny is that a homemade tinfoil hat will provide the same health benefits at a fraction of the cost.

And that can protect you from mind control rays too!

http://zapatopi.net/afdb.html

Gone West

why dont you take this outside? or play lan ut24k or something to settle your differences?

causal

bminish wrote:

The Faraday shield does not do anything about the magnetic field, to demonstrate try the following experiment
wrap thoroughly your mobile in aluminium foil, now call it. it will be out of coverage if you did a good enough job on the wrapping
Now wrap one steel nut in foil, pick it up with a magnet, since you can pick it up you have just demonstrated that a Faraday shield has no effect on the magnetic field for that you need magnetic shielding such as MuMetal.

Using a material with a lower magnetic 'resistance' than the strength of the magnetic field it is exposed to, simply proves that it possible for a Faraday shield to be broken down. It does not prove that a Faraday shield does nothing for a magnetic field, to wit your use of a Faraday shield below:

bminish wrote:

Mu Metal (Which I have used to shield Oscilloscope CRT tubes in close proximity to PSU transformers) Is extremely expensive, has it's magnetic shielding properties damaged by heat, bending, mishandling and has quite a low magnetic saturation point . it's a specialist material that is only used for specialist applications such as your link suggests.

But it works, that's the point - so how can you still say that a Faraday cage does nothing for magnetic fields?

And you've moved this particular point far from where it started.
Your original question was whether the anti powerline lobbyists request for UG cabling was "illogical".
Now you're moving onto whether using Faraday shielding on HT UG lines is 'practical';

bminish wrote:

A shield such as this could not be used around underground power lines, do you understand how a transformer works by coupling into the near magnetic field of a conductor carrying AC? Good.
Now you will understand why effective magnetic shielding of HT lines is not as a rule done, underground or overground.

Again you're talking about the practicality.
Out of curiosity: how big would a UG HT cable near field be, and does the shielding _have_ to be put in the near field?

bminish wrote:

Round in circles we go again, There is no evidence of risk either, even at mobile phone handset type exposure levels which are orders of a magnitudes larger (mainly due to proximity to the user) than exposure from WiFi, Mobile base stations or DECT base stations.

Maybe you misunderstand the word 'risk'.
There is a risk. There may be no actual negative effects, but there may be. That possibility constitutes a risk.

bminish wrote:

Your disagreement contradicts your own statement that science can't prove something is safe:
You stated that science can't prove these items are safe, therefore there is a _risk_ by being exposed to them

NO! Just because something isn't proven to be safe does not mean that it is correct to assume that it is dangerous.

Again, I used the word "_risk_"; I did not say 'it is dangerous'.

bminish wrote:

if low level exposure to microwaves is dangerous then it's logical also to conclude that low level exposure to light (& I DO mean low*) is also harmful

With respect, that's a simplistic view.
Sure the energy of an individual photon is determined by it's frequency; and microwaves < visible < x-ray < gamma
But there are other factors to consider such as intensity, resonance.
Higher frequency microwaves are close to the cellualr size:
[url] http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html [/url]

bminish wrote:

* If a 100mW WiFi base station was instead replaced by a conventional torchbulb with 5% visible efficiency (the other 95% is mostly radiated as Infra red photons) one would need to power that bulb with 2w for 100mW of the applied power to be radiated as visible E/M radiation. Not very bright a couple of metres away is it?

No but the comparison isn't very bright either.
The major flaw is that you are measuring the _illumination of the objects surrounding the bulb_, that is totally irrelevent.
If you take a bulb - rated for 2W (slightly less than a typical bicycle bulb which is about 5W) and switch it on in the black of night - you will see the light emitted from that bulb from hundreds of meters away.

And it's the same for wifi routers "Long Operating Range Supports 91m (Indoors) and 457m (Outdoors)"
[url] http://www.linksys.com/products/product.asp?prid=540&scid=35 [/url]

bminish wrote:

I don't think you have misquoted me but you have played fast and loose with the various reports etc you have been quoting.

'fast and loose' - I quoted verbatim from all references and provided direct links to them.



causAl

causal

doodle_sketch wrote:

Is it fair to conclude that you acknowledge that wifi routers, DECT phones, mobile phones, powerlines can't be proven to be unsafe?

In short: No.

In an attempt to start bringing some conclusions to this discussion I'll go further because I suspect, based on some of the questions put my way, that people jumped to their own conclusions about my thinking.

I answer no to your question because it can (particularly in acute situations) be easier to prove something is unsafe than to prove something is safe.

It's fair to assert, given the above statement, that one would expect to find conclusive evidence of acute harmful effects of EMR. At this juncture that is not the case, there is, reputedly, little or no evidence to support the proposition that there are hazzardous effects of EMR.

This could be the case for one of two broad reasons:
1) the data or the analysis and conclusions drawn are flawed
2) there is in fact little/no acute harmful effects of EMR.

I'm more disposed, for acute effects, towards reason 2, but I do not rule out reason 1. Some people totally dismiss 1, as is their choice.


However, any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough.
In practice, I choose to err on the side of safety on the risk of long term effects of EMR

causAl

causal

oscarBravo wrote:

I don't think it's about risk thresholds, per se. I'm actually quite risk-averse: I don't tend to participate in dangerous activities if I can avoid them. Your avoidance of WiFi seems to me to be on a par with refusing to leave your house because of the risk of being hit by a meteorite.

LOL. If a meteorite hits I don't think being in my house will offer much protection But I might get my roof reinforced just in case, maybe add a little tinfoil too, no I'll go the whole hog and add a Faraday cage!
Seriously though, I think the jury is out on the long term effects.

oscarBravo wrote:

The preponderance of evidence is that, on balance of probability, there is no risk from EMR. That's good enough for me.

I agree with you on that for the short-term effects.

oscarBravo wrote:

I thought you might. Don't you think you're being inconsistent by having them? After all, you've pointed out yourself the fact that ionising radiation has been clearly demonstrated to cause health problems. How can you justify having four active sources of ionising radiation in your house?

Maybe I am inconsistent, but it's a small increase in risk. And apparently I have more than four sources!!! -
Internal radiation :eek: accounts for 11% of my annual dosage; Radon accounts for 54%; Consumer products account for 3%.
Check out [url] http://www.physics.isu.edu/radinf/popdose.htm [/url]
and [url] http://www.physics.isu.edu/radinf/radrus.htm [/url]
It made interesting reading (well for me anyway because I didn't have those figures in my head)

Radiation in the home
There are some small sources of radiation in the home. Your television set accelerates electrons to make the picture on the screen, and produces a few low energy x-rays. Smoke detectors contain small sources in them. These sources emit radiation that are easily stopped even by smoke, and that way detect the presence of smoke. The sources of radiation around the home, not counting natural sources like radon, tend to make up a small fraction of the background dose.

According to the above link my total annual dosage is 0.360 Rem/yr,
and according to [url] http://www.physics.isu.edu/radinf/hprisk.htm [/url] as long as I'm below 5 Rem/yr "zero health effects is the most likely outcome".

Epidemiological studies have not demonstrated adverse health effects in individuals exposed to small doses (less the 10 rem) delivered in a period of many years.
...
In view of the above, the Society has concluded that estimates of risk should be limited to individuals receiving a dose of at least 5 rem in one year or a lifetime dose of at least 10 rem in addition to natural background. Below these doses, risk estimates should not be used; expressions of risk should only be qualitative emphasizing the inability to detect any increased health detriment (i. e. zero health effects is the most likely outcome).

Needless to say, I'll keep an open mind

causAl

causal

FuzzyLogic wrote:

why dont you take this outside? or play lan ut24k or something to settle your differences?

In fairness, I've found the discussion interesting. Sorry to those who didn't - but hey what the hell did ya keep reading it for if it wasn't interesting

I've certainly benefitted from the posts. I've a more defined understanding of this whole issue. For me that makes it useful and worthwhile :cool:

causAl

PS I play Ghost Recon on ubi.com occasionally so if anyone's looking for combat ...

bminish

causal wrote:

Using a material with a lower magnetic 'resistance' than the strength of the magnetic field it is exposed to,

Horse****!

simply proves that it possible for a Faraday shield to be broken down. It does not prove that a Faraday shield does nothing for a magnetic field, to wit your use of a Faraday shield below:



But it works, that's the point - so how can you still say that a Faraday cage does nothing for magnetic fields?

Because magnetic Shielding is quite separate from the actions of a faraday cage, a farady Cage does nothing to block or reduce magnetic fields it is simply an electrostatic screen, that is all
http://en.wikipedia.org/wiki/Faraday_cage

And you've moved this particular point far from where it started.
Your original question was whether the anti powerline lobbyists request for UG cabling was "illogical".
Now you're moving onto whether using Faraday shielding on HT UG lines is 'practical';

it is illogical to seek for HT lines to be placed underground to reduce magnetic exposure since in many cases it will in fact increase magnetic exposure

it isn't practical to provide them with magnetic screening since doing so would cause very high losses in the line (generating much heat), be extremely expensive and require exotic and hard to handle alloys

Again you're talking about the practicality.
Out of curiosity: how big would a UG HT cable near field be, and does the shielding _have_ to be put in the near field?

How big ? utterly dependant on the amount of current that it is carrying, how close it is to the other phases and how well balanced the phases are. Same rules as for an overground line !

It actually makes the most sense to put the shielding at a distance and just where it is needed

Again, I used the word "_risk_"; I did not say 'it is dangerous'.

What risk?

With respect, that's a simplistic view.
Sure the energy of an individual photon is determined by it's frequency; and microwaves < visible < x-ray < gamma
But there are other factors to consider such as intensity, resonance.
Higher frequency microwaves are close to the cellualr size:
[url] http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html [/url]

And your point is?

No but the comparison isn't very bright either.
The major flaw is that you are measuring the _illumination of the objects surrounding the bulb_, that is totally irrelevent.
If you take a bulb - rated for 2W (slightly less than a typical bicycle bulb which is about 5W) and switch it on in the black of night - you will see the light emitted from that bulb from hundreds of meters away.

No it's absolutely relevant both are E/M radiation the illumination in this case IS the exposure level, ask any photographer

Can light have an intensity at which exposure is dangerous? certainly
Is exposure to the 2w torchbulb dangerous? No

And it's the same for wifi routers "Long Operating Range Supports 91m (Indoors) and 457m (Outdoors)"
[url] http://www.linksys.com/products/product.asp?prid=540&scid=35 [/url]

and your point is?
I am connected to a WiFi AP at a distance of 14Km


.Brendan

causal

bminish wrote:

causal wrote:

Using a material with a lower magnetic 'resistance' than the strength of the magnetic field it is exposed to,

Horse****!

Where's the horse bosco? Certain materials dampen magentic fields. 'How much' they dampen the magnetic field I referred to above as "magnetic 'resistance'". And I was saying that if the strength of the magnetic field is greater than the threshold of the damping material - then some of the magnetic field will penetrate.

bminish wrote:

Because magnetic Shielding is quite separate from the actions of a faraday cage, a farady Cage does nothing to block or reduce magnetic fields it is simply an electrostatic screen, that is all
http://en.wikipedia.org/wiki/Faraday_cage

You still don't get it, so I'll quote (again) from [url] http://www.emishieldinggaskets.com/faraday_cage _tent.htm [/url]:

Mu-copper foil is used in shielded rooms, shielded chambers and faraday cages and has high damping properties in the electrical field (up to 120dB) as well as in the magnetic field

bminish wrote:

What risk?

The risk of negative effects on health from EMR.

bminish wrote:

No it's absolutely relevant both are E/M radiation the illumination in this case IS the exposure level, ask any photographer

If you're talking about how well the human eye perceives the illuminated objects 2 metres away from the bulb then it is totally irrelevant.

If, however, you're talking about the measured intensity 2 metres away from the bulb then I would disagree with your original rhetorical question:

"Not very bright a couple of metres away is it?

I would say that a 2watt bulb is very bright from 2 metres away, and so would any photographer, and so would any astronomer.

bminish wrote:

Can light have an intensity at which exposure is dangerous? certainly
Is exposure to the 2w torchbulb dangerous? No

Whether or not that be the case, it says nothing about the risk of 2W in other regions of the spectrum. Recall:

Higher frequency microwaves are close to the cellualr size:
[url] http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html [/url]

causAl

bminish

causal wrote:

Where's the horse bosco? Certain materials dampen magentic fields. 'How much' they dampen the magnetic field I referred to above as "magnetic 'resistance'".

The term you are searching for is permeability, Mumetal has a very High magnetic permeability and is as a result quite an exotic alloy

You still don't get it, so I'll quote (again) from [url] http://www.emishieldinggaskets.com/faraday_cage _tent.htm [/url]:

I get it perfectly, it's you that's mixing things up
magnetic shielding is QUITE separate from the electrostatic screening that a Faraday cage provides. A magnetic shield is NOT a Faraday cage

go and read the wikipedai definition of a Faraday cage again

The risk of negative effects on health from EMR.

Are essentially Nil at currently permitted levels.

If you're talking about how well the human eye perceives the illuminated objects 2 metres away from the bulb then it is totally irrelevant.

If, however, you're talking about the measured intensity 2 metres away from the bulb then I would disagree with your original rhetorical question:

I would say that a 2watt bulb is very bright from 2 metres away, and so would any photographer, and so would any astronomer.

Photographers and astronomers can detect individual photons, parially because light photons are fairly energetic in comparison to RF photons.

I can pick up 1 watt HF radio signals from the other side of the planet when HF radio conditions are good but your point is please ?

Whether or not that be the case, it says nothing about the risk of 2W in other regions of the spectrum. Recall

Yes, so high frequency microwave wavelengths up in the Thz (Terra Hz) are approaching cellular size, What is your point please?

Frequencies this high are not in current common usage in any case because they are hard to generate and even harder to detect at low levels.


Wifi (802.11b & 802.1G) uses 2.4 ghz with a wavelength of about 13 Cm, not nanometers or mm but Centimetres, Not cellular sized.
WiFi (802.11a) uses 5.8Ghz with a wavelength of about 5.2Cm
Mobile phones use ~900 Mhz 33 Cm
and 1.8 Ghz 16 Cm
DECT 1.7Ghz 17.6Cm

.Brendan

causal

bminish wrote:

magnetic shielding is QUITE separate from the electrostatic screening that a Faraday cage provides. A magnetic shield is NOT a Faraday cage
go and read the wikipedai definition of a Faraday cage again

Since you refute the previous references I've given, this time I'll quote from the reference _you_ give
[url] http://en.wikipedia.org/wiki/Faraday_cage [/url]
N.B. This quote is directly from the section "Real-world Faraday cages":

Faraday cages are often put to a dual purpose: to block electric fields, as explained above, and to block electromagnetic radiation. The latter application is known as RF shielding.

Do you get it now?
"Faraday cages are often put to a dual purpose: to block electric fields, as explained above, and to block electromagnetic radiation.

bminish wrote:

Wifi (802.11b & 802.1G) uses 2.4 ghz with a wavelength of about 13 Cm, not nanometers or mm but Centimetres, Not cellular sized.

At c = 3.0 x 10^8, a frequency of 2.4GHz gives a wavelength of 12.5cm, notwithstanding any FM.

A quick search for body parts with a size of 12.5 cm yielded interesting results:
average size of male penis - http://www.news-medical.net/?id=6728
a moderately full bladder :eek: - http://people.morehead-st.edu/fs/m.mcmurr/231-L20.html
liver (antero-posterior diameter) - http://www.bartleby.com/107/pages/page1188.html
18 week old fetus (crown-to-rump) - http://www.mdadvice.com/library/urpreg/wbw18.htm



I'll reiterate:

"any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough".

You may choose to continue to state that they're "completely safe", but your assertions are unsupported, you do not have the long term data, it does not exist yet.


causal

bminish

causal wrote:

Since you refute the previous references I've given, this time I'll quote from the reference _you_ give
[url] http://en.wikipedia.org/wiki/Faraday_cage [/url]
N.B. This quote is directly from the section "Real-world Faraday cages":


Do you get it now?
"Faraday cages are often put to a dual purpose: to block electric fields, as explained above, and to block electromagnetic radiation.

I get it perfectly, you still don't!

You brought up faraday shielding in relation to magnetic shielding, particularly in relation to power lines which operate at 50 hz . This is something that at faraday shield simply doesn't do

RF shielding, yes a faraday cage will do that. Electrostatic Shielding, Yes
Magnetic shielding, NO a faraday cage won't do that.

.Brendan

bminish

Irrelevant ****e about body part size chopped out. Just because something is the same size does not mean that it is resonant, look up velocity factor

causal wrote:

I'll reiterate:

"any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough".

You may choose to continue to state that they're "completely safe", but your assertions are unsupported, you do not have the long term data, it does not exist yet.

There are now over 50 years worth of data on human and animal exposure to microwaves, yet no evidence of 'Chronic effects'

.Brendan

causal

bminish wrote:

You brought up faraday shielding in relation to magnetic shielding, particularly in relation to power lines which operate at 50 hz . This is something that at faraday shield simply doesn't do

No. Let's review what actually happened:

You brought up the following http://www.boards.ie/vbulletin/showpost.php?p=2350424&postcount=10
"One of the funny things is that the anti-power-line lobby want them placed under ground, this places people much closer to the line. Illogical argument don't you think! "


Then I said http://www.boards.ie/vbulletin/showpost.php?p=2350722&postcount=11
"That depends on how it's implemented and whether the cables are located near residential areas. <snip> If the cables are properly shielded then the EM field outside the cable should be zero/minimal."


You replied http://www.boards.ie/vbulletin/showpost.php?p=2357766&postcount=18
"BTW the underground argument posted earlier is bunk, insulation is not relevant to the E and M fields"

But now you acknowledge: [url] http://www.boards.ie/vbulletin/showpost.php?p=2372843&postcount=37 [/url]

bminish wrote:

RF shielding, yes a faraday cage will do that. Electrostatic Shielding, Yes
Magnetic shielding, NO a faraday cage won't do that.

So the critical point is that, as I said ealier, the cables can be properly shielded - and when you said that was bunk - you were wrong.
The fact remains that 50Hz electromagnetic fields from powerlines can be shielded:

http://www.emfservices.com/emf-shielding.htm

ELF Electric (50/60 Hz) - Easily shielded with any grounded conductive barrier, from metal screen to a row of trees. Electric fields are most commonly a problem for electrosensitive people.
ELF Magnetic (50/60 Hz) - Passive Magnetic Shielding with Bulk Materials - often a combination of high conductivity and high permeability metal plates.
ELF Magnetic (50/60 Hz) - Magnetic Field Cancellation (Active EMF Shielding) Restore Circuit Balance.

http://www.ce-mag.com/99ARG/Bjorklof137.html

Low-frequency magnetic fields are more difficult to shield against. However, whereas absorption shielding typically calls for the installation of thick shields constructed of fairly expensive magnetic materials, shields based on the induced-current principle may be reasonably effective at power-line frequencies. Consequently, aluminum screens are commonly used to protect against 50- and 60-Hz magnetic fields generated by transformers and other sources.

http://www.takenaka.co.jp/takenaka_e/techno/n42_actshld/n42_actshld.htm

Using the active magnetic shield as a stand-alone system, shielding effectiveness of 20 db (1/10) can be achieved against direct current to around 50 to 60 Hz.

http://www.vitatech.net/magnetic_shielding.html

There are two basic types of 60-Hz magnetic shields: flux-entrapment shields and lossy shields. A flux-entrapment shield is constructed with ferromagnetic, highly permeable (µ-mu), 80% nickel-20% iron alloy (i.e., Hipernom Alloy, CO-NETIC AA, Aumetal, AD-MU-80, etc.) which either surrounds (cylinder or rectangular box) or separates ("U" shaped or flat-plate) the area from the magnetic source.

causAl

causal

bminish wrote:

There are now over 50 years worth of data on human and animal exposure to microwaves, yet no evidence of 'Chronic effects'

Regardless of whether that is or is not the case, the fact remains:
There are NOT over 50 years worth of data on human and animal exposure to wifi/mobiles/dect.

Do you not understand the difference?
People have not spent the last 50 years with microwave transmitting mobile phones in their pockets, and against their heads;
People have not spent the last 50 years with microwave transmitting dect phones in their homes, and against their heads;
People have not spent the last 50 years with microwave transmitting wifi routers in their homes, and in their workplace.

I'll reiterate:
"any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough".


causAl

bminish

ELF Electric (50/60 Hz) - Easily shielded with any grounded conductive barrier, from metal screen to a row of trees. Electric fields are most commonly a problem for electrosensitive people.

yes grounded conductive barrier will do electrostatic shielding. This is how the faraday cage works !

The effects of trees would be marginal at best but not being able to see the powerlines combined with a belief that they help may make people feel a whole lot better, nothing to do with physics though

ELF Magnetic (50/60 Hz) - Passive Magnetic Shielding with Bulk Materials - often a combination of high conductivity and high permeability metal plates.

Expensive and lossy, the magnetic field is a function of the power being carried . absorbing it in the near field 'robs' power from the circuit generating heat.

ELF Magnetic (50/60 Hz) - Magnetic Field Cancellation (Active EMF Shielding) Restore Circuit Balance.

Actually this is why the near field around HT power lines is usually pretty low. They are already balanced.

Low-frequency magnetic fields are more difficult to shield against. However, whereas absorption shielding typically calls for the installation of thick shields constructed of fairly expensive magnetic materials, shields based on the induced-current principle may be reasonably effective at power-line frequencies. Consequently, aluminum screens are commonly used to protect against 50- and 60-Hz magnetic fields generated by transformers and other sources.

IF you understood how this actually worked you would see why it is never used for anything other than dealing with residual stray fields from things like transformers

It works because the AC magnetic field induces eddy currents in the non-ferrous material, these currents are shorted out creating an opposing field of nearly equal flux density

Go and look up the principles of the induction furnace to see why this is not a practical solution for most applications (such as shielding power lines )

Using the active magnetic shield as a stand-alone system, shielding effectiveness of 20 db (1/10) can be achieved against direct current to around 50 to 60 Hz.

Not a near field or general solution.
In the near field this would have the same power loss (heat generation) problems as using non ferrous materials in the near field.

.Brendan

bminish

causal wrote:

Regardless of whether that is or is not the case, the fact remains:
There are NOT over 50 years worth of data on human and animal exposure to wifi/mobiles/dect.

Unless you can back up your claim that GSM / DECT / WiFI are different in some way your argument simply doesn't hold water.
People have been exposed occupationally on a daily basis to levels well above current (handset / dect / Wifi) sar levels since the 1940's

Where are all the dead Radar tecs
What about all those dead fishermen (marine radar operates with pulses of up to 120Kw EIRP )
What about commercial Kitchen workers, (Industrial microwave ovens)
What about TV, broadcast and telecom transmitting engineers ?

Don't forget that occupational exposure limits are 5 times the current public exposure limits

I'll reiterate:
"any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough".

Ill founded FUD i am afraid

.Brendan

causal

bminish wrote:

yes grounded conductive barrier <BIG SNIP>

I will again state the point which you consistently try to ignore:

"So the critical point is that, as I said ealier, the cables can be properly shielded - and when you said that was bunk - you were wrong.
The fact remains that 50Hz electromagnetic fields from powerlines can be shielded:"

EM fields from powerlines CAN be shielded - fact - not bunk - and you have no basis in fact to state otherwise.

Do you wish to maintain that EM fields from powerlines cannot be shielded, despite the evidence to the contrary?
Do you wish to accept that EM fields from powerlines can be shielded, in agreement with my statments, and the evidence, and withdraw your statement that it was bunk?


causAl

causal

bminish wrote:

causal wrote:

Regardless of whether that is or is not the case, the fact remains:
There are NOT over 50 years worth of data on human and animal exposure to wifi/mobiles/dect.

Unless you can back up your claim that GSM / DECT / WiFI are different in some way your argument simply doesn't hold water.

No. Once again you are misrepresenting the facts.

I said:
"You may choose to continue to state that they're "completely safe", but your assertions are unsupported, you do not have the long term data, it does not exist yet."

To which you replied:
"There are now over 50 years worth of data on human and animal exposure to microwaves, yet no evidence of 'Chronic effects'"

So, you are the one who tried to equate the two. The onus is on you to back up your claim.

Whichever way you want to turn it around, to prove or disprove the thesis you need to gather an equivalent 50 years of data for gsm/dect/wifi, and do a comparative analysis between the two datasets.
That concurs with my statment that the data doesn't exist for gsm/wifi/dect either alone, or comparatively.
And it will take a long time to gather it.

bminish wrote:

causal wrote:

"any potential chronic effects of wifi/mobiles/dect etc. won't be seen for another 20 years or so, they simply haven't been around long enough".

Ill founded FUD i am afraid

There is no individual or comparative evidence to support your statement. It stands alone.


causAl

bminish

causal wrote:

I will again state the point which you consistently try to ignore:


EM fields from powerlines CAN be shielded - fact - not bunk - and you have no basis in fact to state otherwise.

You can screen a room or an area at a distance from the cables, i have never argued otherwise, you cannot however screen the cables themselves. I have outlined in some detail why this is the case.

.Brendan

bminish

causal wrote:

No. Once again you are misrepresenting the facts.

I said:
"You may choose to continue to state that they're "completely safe", but your assertions are unsupported, you do not have the long term data, it does not exist yet."

To which you replied:
"There are now over 50 years worth of data on human and animal exposure to microwaves, yet no evidence of 'Chronic effects'"

So, you are the one who tried to equate the two. The onus is on you to back up your claim.

No it is not up to me, you are the one that is claiming that all this past data is not valid without showing why it is not relevant.

it's ill informed FUD on your part.

.Brendan

causal

bminish wrote:

No it is not up to me, you are the one that is claiming that all this past data is not valid without showing why it is not relevant.

No. You are the one who is claiming that it is valid - presumably that's why you brought it up in the first place. You never established a link, except that wifi/dect/gsm are microwaves and data was gathered about microwaves. Is that it?


causAl

causal

bminish wrote:

You can screen a room or an area at a distance from the cables, i have never argued otherwise, you cannot however screen the cables themselves. I have outlined in some detail why this is the case.

Ok so let's see if we can agree on something:

It is possible to screen the EMR from powerline cables (perhaps by having them in screened tunnels, whatever), however for common usage it is neither practical nor economically viable.



causAl

bminish

causal wrote:

Ok so let's see if we can agree on something:

It is possible to screen the EMR from powerline cables (perhaps by having them in screened tunnels, whatever), however for common usage it is neither practical nor economically viable.
causAl

A tunnel is a bit too close to being nearfield at 50 hz and as a result a MuMetal lined tunnel would be somewhat lossy as well as being just a touch pricey.

[edit] but yes it would work, but why on earth would you want to do it?

.Brendan

bminish

causal wrote:

No. You are the one who is claiming that it is valid - presumably that's why you brought it up in the first place. You never established a link, except that wifi/dect/gsm are microwaves and data was gathered about microwaves. Is that it?

In a nutshell yes.

The frequencies are very similar (in some cases the same ) the exposure levels (at the head, body etc) are broadly similar (or indeed above) exposure levels from GSM handsets, DECT WiFi etc.
Yes they are further away from the head but the power levels are vastly larger, in many cases producing SAR levels to workers near the maximum occupational exposure levels.
In the case of both radar and microwave oven exposure the E/m radiation is pulsed (some folk are claiming that pulsed E/M radiation is is some way more harmful than steady state fields )
The durations of exposure are in many cases also similar (often entire working days, every day for years )

.Brendan

causal

bminish wrote:

[edit] but yes it would work

Wahaay!

bminish wrote:

but why on earth would you want to do it?

The only types I can think of that might have any 'practical' purpose might be scientists for research, or the military for their own reasons.


causAl