Networking Forums

Networking Forums > Wireless Networking > Wireless Internet > Is there any harmful effect from wifi (802.11.x) radiation? Anydefinitive proof?

Reply
Thread Tools Display Modes

Is there any harmful effect from wifi (802.11.x) radiation? Anydefinitive proof?

 
 
Penang
Guest
Posts: n/a

 
      09-25-2008, 04:38 AM
Hello, all.

I am part of the task force to set up a city-wide wifi coverage in
Penang, Malaysia.

However, there's a group appeared on the local scene opposing the city-
wide wifi coverage, on the ground that the "radiation from wifi is
extremely harmful to health" and they quote "an internationally known
expert" (a German) who wrote a book with the title of "Stress durch
Strom und Strahlung" to state their point.

Personally, I don't know the German language. It's Greek to me.

But I'm here posting this question to all you Gurus anyway ...

Is there any _PROVEN_ harmful effect stemming from the wireless
radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
and in the 5GHz band (for 802.11n) ?

Although I am part of the team deploying the city-wide wifi coverage,
I want to be sure that what I am doing would NOT cause any harmful
effect to the people of this city.

Can you help, please?

Thank you all !!!
 
Reply With Quote
 
 
 
 
RF
Guest
Posts: n/a

 
      09-25-2008, 05:47 AM
Penang wrote:
> Hello, all.
>
> I am part of the task force to set up a city-wide wifi coverage in
> Penang, Malaysia.
>
> However, there's a group appeared on the local scene opposing the city-
> wide wifi coverage, on the ground that the "radiation from wifi is
> extremely harmful to health" and they quote "an internationally known
> expert" (a German) who wrote a book with the title of "Stress durch
> Strom und Strahlung" to state their point.
>
> Personally, I don't know the German language. It's Greek to me.
>
> But I'm here posting this question to all you Gurus anyway ...
>
> Is there any _PROVEN_ harmful effect stemming from the wireless
> radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
> and in the 5GHz band (for 802.11n) ?
>
> Although I am part of the team deploying the city-wide wifi coverage,
> I want to be sure that what I am doing would NOT cause any harmful
> effect to the people of this city.
>
> Can you help, please?
>
> Thank you all !!!


I hope this helps for a start. As you see, Europe
is much more health concious than the US. Good
luck with your battle :-)
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++++++

http://environment.independent.co.uk...cle2944417.ece

Germany warns citizens to avoid using Wi-Fi

Environment Ministry's verdict on the health risks
from wireless technology puts the British
government to shame.
By Geoffrey Lean

Published: 09 September 2007

People should avoid using Wi-Fi wherever possible
because of the risks it may pose to health, the
German government has said.

Its surprise ruling – the most damning made by any
government on the fast-growing technology – will
shake the industry and British ministers, and
vindicates the questions that The Independent on
Sunday has been raising over the past four months.

And Germany's official radiation protection body
also advises its citizens to use landlines instead
of mobile phones, and warns of "electrosmog" from
a wide range of other everyday products, from baby
monitors to electric blankets.

The German government's ruling – which contrasts
sharply with the unquestioning promotion of the
technology by British officials – was made in
response to a series of questions by Green members
of the Bundestag, Germany's parliament.

The Environment Ministry recommended that people
should keep their exposure to radiation from Wi-Fi
"as low as possible" by choosing "conventional
wired connections". It added that it is "actively
informing people about possibilities for reducing
personal exposure".

Its actions will provide vital support for Sir
William Stewart, Britain's official health
protection watchdog, who has produced two reports
calling for caution in using mobile phones and who
has also called for a review of the use of Wi-Fi
in schools. His warnings have so far been ignored
by ministers and even played down by the Health
Protection Agency, which he chairs.

By contrast the agency's German equivalent – the
Federal Office for Radiation Protection – is
leading the calls for caution.

Florian Emrich, for the office, says Wi-Fi should
be avoided "because people receive exposures from
many sources and because it is a new technology
and all the research into its health effects has
not yet been carried out".


++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++
Health concerns over mobile phone masts prompt
review
'IoS' report on the dangers of electronic smog
from wireless technology examined by ministers
By Marie Woolf and Geoffrey Lean
Published: 13 May 2007

Ministers are to investigate arrangements for
erecting mobile phone masts in the light of
growing fears that they may cause cancer and other
diseases because of "electronic smog".

They will review the exceptionally favourable
rules that allow mobile phone companies to escape
normal planning regulations and stop councils from
considering the effects of the masts on health,
even when they are sited near homes and schools.

Originally promised three years ago, and then
shelved, the review follows articles in The
Independent on Sunday about possible effects of
the radiation on children and bees. The Government
will take account of new scientific and medical
evidence, and consult experts and campaigners, as
part of a wider review of planning guidelines
which ministers send to local authorities.

More than 47,000 "base stations", like masts, have
already been erected in Britain to service its 50
million mobile phones, often in defiance of
intense local public opposition. Successive
governments have made extraordinary concessions to
the companies to ensure that coverage was rolled
out across the country as quickly as possible.

Masts up to 45ft high do not need planning
permission in the normal way. Instead, companies
merely have to notify councils of their intentions
and can go ahead unless they are formally stopped
within 56 days.

Overworked planning authorities struggle to cope
with these applications on time, and companies
have frequently put up the masts against councils'
opposition because news of a refusal has reached
them shortly after the deadline.

Seven years ago, an official inquiry - headed by
Sir William Stewart, a former government chief
scientist - concluded that "the siting of all new
base stations should be subject to the normal
planning process".

Ministers said that they were "minded" to
implement this recommendation, and then failed to
do so, even though full planning permission has
long been required in Scotland and Northern Ireland.

The inquiry also urged that masts should not be
built near schools unless parents agreed, but
ministers refused to agree.

The planning rules also make it clear that
councils cannot object to masts on health grounds
because "the planning system is not the place for
determining health safeguards". Yet studies are
revealing worrying levels of symptoms such as
headaches, fatigue, nausea, dizziness,
difficulties in sleeping and concentrating, and
learning and memory problems in people living near
the masts - and there is also some suggestion that
there may be an increase in cancers and heart disease.

Nevertheless, councils are instructed by the rules
to "respond positively" to the phone companies'
plans and, in practice, can reject a mast only on
aesthetic grounds. The Deputy Prime Minister, John
Prescott, promised a review by the end of 2004. It
never took place, but last week the Department for
Communities and
http://news.independent.co.uk/uk/hea...cle2536863.ece

Local Government confirmed that the advice to
local authorities is to be re-examined.

A spokesman for the department said: "We are
examining developments in research on this issue.
It is something that is going to be looked at."

Parents fight Wi-Fi at primary school

Parents have been battling plans to install a
Wi-Fi only system in their children's school in
north London for the past two years. They are
worried that the health implications of Wi-Fi have
not been fully researched and radioactivity
created by the technology could harm the children
at Tetherdown Primary School. They argue it is
better and cheaper to install cables with local
Wi-Fi connectors.

Rani Jowett, 35, who has three children at the
school, said: "It's taking a risk with our
children because it's still under study. People in
the 1950s took a risk with smoking, but we have
the power to stop this. In my own home I have a
choice over Wi-Fi, but I don't have the choice in
school."

Governors, however, claim that a wired
infrastructure would be too expensive. A spokesman
for Haringey council said: "Safety standards for
this sort of equipment are set nationally and we
follow government guidelines."

Andrew Johnson

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++

http://news.independent.co.uk/health/article2790973.ece

Wi-Fi fears to be investigated
By Geoffrey Lean, Environment Editor
Published: 22 July 2007

Britain's top environmental investigative body is
considering looking into radiation from mobile
phones and their masts, Wi-Fi networks and
electric power lines following articles in The
Independent on Sunday.

The Royal Commission on Environmental Pollution –
an independent group of experts – has shortlisted
the issue for its next study.

In April this newspaper exclusively reported that
Sir William Stewart, the chairman of the Health
Protection Agency, wanted an inquiry into the use
of Wi-Fi in schools, voicing concerns that were
followed up by BBC's Panorama.

"The electromagnetic environment" is one of seven
topics listed – which also includes "noise
pollution", "water management" and "plastics and
the environment". Sir John Lawton, who chairs the
royal commission, says that "any one of these
topics could make a worthwhile study" and is
asking for the public's views to help make a decision.


++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++

Tips to Limit Your Damage from Information
Carrying Radio Waves

There quite simply is no safe biological threshold
for exposure to information-carrying radio waves,
and there is, quite honestly, little you can do to
avoid them 100 percent. But you can reduce your,
and your family’s, exposure by taking the
following commonsense precautions:

* Limit the amount of time you spend on a
cell phone or cordless phone.
* Use a wired headset to limit your exposure
to the cell phone-ideally, an air tube headset
that conducts sound but prevents any radiation
from traveling up the wire to your brain. Also
make sure the wire is SHIELDED, which prevents the
wire from acting as an antenna that could attract
more information-carrying radio waves directly to
your brain. Wireless BlueTooth® headsets should be
avoided.
* Limit your exposure to WiFi routers. Find
out where they are located in your work
environment and stay away from them.
* If you have any land-based (non-cellular)
portable phones, do NOT use anything other than
the 900 MHz phones as the Gigahertz phones stay on
continuously, blasting you with
information-carrying radio waves 24/7.
* Use the speakerphone instead of putting the
phone to your ear; this is probably one of the
single most important steps you can take other
than not using your cell phone.
* Limit calls inside buildings.
* Use the phone in open spaces as often as
possible.
* Limit use by children and preadolescents,
or don’t let them use cell phones at all.
Children’s developing nervous systems and thinner
skulls are simply too vulnerable to cell phone damage.

Use the following link to locate transmitters
(towers, antennas) in your area.

http://www.antennasearch.com/

++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++
Apologies for not keeping the source of the
article above
++++++++++++++++++++++++++++++++++++++++++++++++++ ++++++++++.

Mobile phones 'more dangerous than smoking'

http://www.independent.co.uk/life-st...ng-802602.html
Brain expert warns of huge rise in tumours and
calls on industry to take immediate steps to

By Geoffrey Lean
Sunday, 30 March 2008

Mobile phones could kill far more people than
smoking or asbestos, a study by an award-winning
cancer expert has concluded. He says people should
avoid using them wherever possible and that
governments and the mobile phone industry must
take "immediate steps" to reduce exposure to their
radiation.

The study, by Dr Vini Khurana, is the most
devastating indictment yet published of the health
risks.

It draws on growing evidence – exclusively
reported in the IoS in October – that using
handsets for 10 years or more can double the risk
of brain cancer. Cancers take at least a decade to
develop, invalidating official safety assurances
based on earlier studies which included few, if
any, people who had used the phones for that long.

Earlier this year, the French government warned
against the use of mobile phones, especially by
children. Germany also advises its people to
minimise handset use, and the European Environment
Agency has called for exposures to be reduced.

Professor Khurana – a top neurosurgeon who has
received 14 awards over the past 16 years, has
published more than three dozen scientific papers
– reviewed more than 100 studies on the effects of
mobile phones. He has put the results on a brain
surgery website, and a paper based on the research
is currently being peer-reviewed for publication
in a scientific journal.

He admits that mobiles can save lives in
emergencies, but concludes that "there is a
significant and increasing body of evidence for a
link between mobile phone usage and certain brain
tumours". He believes this will be "definitively
proven" in the next decade.

Noting that malignant brain tumours represent "a
life-ending diagnosis", he adds: "We are currently
experiencing a reactively unchecked and dangerous
situation." He fears that "unless the industry and
governments take immediate and decisive steps",
the incidence of malignant brain tumours and
associated death rate will be observed to rise
globally within a decade from now, by which time
it may be far too late to intervene medically.

"It is anticipated that this danger has far
broader public health ramifications than asbestos
and smoking," says Professor Khurana, who told the
IoS his assessment is partly based on the fact
that three billion people now use the phones
worldwide, three times as many as smoke. Smoking
kills some five million worldwide each year, and
exposure to asbestos is responsible for as many
deaths in Britain as road accidents.

Late last week, the Mobile Operators Association
dismissed Khurana's study as "a selective
discussion of scientific literature by one
individual". It believes he "does not present a
balanced analysis" of the published science, and
"reaches opposite conclusions to the WHO and more
than 30 other independent expert scientific reviews".
 
Reply With Quote
 
Calorie
Guest
Posts: n/a

 
      09-25-2008, 05:54 AM
On Sep 25, 12:38*pm, Penang <kalamb...@gmail.com> wrote:
> Hello, all.
>
> I am part of the task force to set up a city-wide wifi coverage in
> Penang, Malaysia.
>
> However, there's a group appeared on the local scene opposing the city-
> wide wifi coverage, on the ground that the "radiation from wifi is
> extremely harmful to health" and they quote "an internationally known
> expert" (a German) who wrote a book with the title of "Stress durch
> Strom und Strahlung" to state their point.
>
> Personally, I don't know the German language. It's Greek to me.
>
> But I'm here posting this question to all you Gurus anyway ...
>
> Is there any _PROVEN_ harmful effect stemming from the wireless
> radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
> and in the 5GHz band (for 802.11n) ?
>
> Although I am part of the team deploying the city-wide wifi coverage,
> I want to be sure that what I am doing would NOT cause any harmful
> effect to the people of this city.
>
> Can you help, please?
>
> Thank you all !!!


There is a hidden domain to electromagnetism physicists haven't
understood yet. Our body also uses this hidden electromagnetic
domain for communication. ELF and other frequencies can mess
up the body communication. That is all there is to it. This may
be more known in the year 2100 when the body hidden
electromagnetic domain is more thoroughly understood. Meanwhile
deaths and illnesses would be the order of the day. For example,
in the past, ladies put radioactive radium in the teeth for
decorations
and asbestos are inhaled in normal fashion, etc. Now we know
the danger. Such is the double edge sword of progress.

cal
 
Reply With Quote
 
billy@MIX.COM
Guest
Posts: n/a

 
      09-25-2008, 07:58 AM
No Spam <(E-Mail Removed)> wrote:

> There are formulas used to calculate the safe distance that must be
> maintained from the actual antenna up on the tower for the given power
> and gain structure of the system. An RF engineer should be checking these
> for each site.


Here's some info regarding how this is dealt with in the USA -

http://www.osha.gov/SLTC/radiofreque...ion/index.html

And a typical company that does this -

http://www.lbagroup.com/associates/rfemissions.php

Billy Y..
 
Reply With Quote
 
hwabnig@ .- --- -. dotat
Guest
Posts: n/a

 
      09-25-2008, 08:16 AM
On Wed, 24 Sep 2008 21:38:19 -0700 (PDT), Penang <(E-Mail Removed)>
wrote:

>Hello, all.
>
>I am part of the task force to set up a city-wide wifi coverage in
>Penang, Malaysia.
>
>However, there's a group appeared on the local scene opposing the city-
>wide wifi coverage, on the ground that the "radiation from wifi is
>extremely harmful to health" and they quote "an internationally known
>expert" (a German) who wrote a book with the title of "Stress durch
>Strom und Strahlung" to state their point.
>
>Personally, I don't know the German language. It's Greek to me.
>
>But I'm here posting this question to all you Gurus anyway ...
>
>Is there any _PROVEN_ harmful effect stemming from the wireless
>radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
>and in the 5GHz band (for 802.11n) ?


No.
Period.

All "prudent avoidance" costs us (whom?) billions of $$
in actions-for-nothing and there have been actual occurrences
of hysteric outbreaks among people living near cell towers,
until the cell company revealed the fact that the new tower
did not have cable connections nor installed equipment yet.
(Graz, Austria, some years ago)

The worst role is played by medical doctors who have a
notorious deficit in physics education and techology.

"This topic requires further funding" for more research.
Print that on your T-shirt, front and back.
It means what it means. Capisci?

w.
 
Reply With Quote
 
hwabnig@ .- --- -. dotat
Guest
Posts: n/a

 
      09-25-2008, 09:04 AM
On Thu, 25 Sep 2008 10:16:49 +0200, hwabnig@ .- --- -. dotat wrote:


>
>"This topic requires further funding" for more research.
>Print that on your T-shirt, front and back.



Wanted to say, then replaced a word:
"This subject requires further funding"

you decide

w.
 
Reply With Quote
 
Davoud
Guest
Posts: n/a

 
      09-25-2008, 01:45 PM
Penang wrote:

> Hello, all.
>
> I am part of the task force to set up a city-wide wifi coverage in
> Penang, Malaysia.
>
> However, there's a group appeared on the local scene opposing the city-
> wide wifi coverage, on the ground that the "radiation from wifi is
> extremely harmful to health" and they quote "an internationally known
> expert" (a German) who wrote a book with the title of "Stress durch
> Strom und Strahlung" to state their point.
>
> Personally, I don't know the German language. It's Greek to me.
>
> But I'm here posting this question to all you Gurus anyway ...
>
> Is there any _PROVEN_ harmful effect stemming from the wireless
> radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
> and in the 5GHz band (for 802.11n) ?
>
> Although I am part of the team deploying the city-wide wifi coverage,
> I want to be sure that what I am doing would NOT cause any harmful
> effect to the people of this city.
>
> Can you help, please?
>
> Thank you all !!!


This is the wrong place to ask such a question. You need the results of
scientific studies, not laymens' opinions--especially on USENET--you'll
end up with the entire population either wearing tinfoil hats or
sticking their heads into microwave ovens to prove it's safe. You
should contact UTM or another school. If they don't have the
information they can point you to research on the subject. Google may
also help.

As always, it is best to avoid studies done by, or on behalf of,
entities that have a financial interest in the outcome of the studies.

Penang--I used to vacation there from time to time. Fabulous!

Davoud

P.S. Now the answer: "No one knows. There may be a risk from exposure
to microwave radiation at the extremely low levels that would be
typical of city-wide WiFi coverage, but if there is, it is almost
certainly a very small risk. Since wireless devices that operate in
higher frequency ranges only came into public use in the 1990's there
is not sufficient data from which to form a judgement. It is believed
that most brain cancers result from radiation treatment for previous
cancers, and they take from 10 to 15 years to appear. It is also true
that in the 1990's children weren't likely to be exposed to RF
radiation from cell phones or WiFi, so it will be years before the
effects of exposure from a young age can be assessed." (Extrapolated
from American Cancer Society reporting on cell phones.)

--
Don't re-elect the past. Vote for the future: Obama in 2008!

usenet *at* davidillig dawt com
 
Reply With Quote
 
D. C. Sessions
Guest
Posts: n/a

 
      09-25-2008, 02:46 PM
Penang wrote:

> Is there any _PROVEN_ harmful effect stemming from the wireless
> radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
> and in the 5GHz band (for 802.11n) ?
>
> Although I am part of the team deploying the city-wide wifi coverage,
> I want to be sure that what I am doing would NOT cause any harmful
> effect to the people of this city.


The frequencies used for WiFi are the same as those used for mobile
telephones. The number of telephones obviously *vastly* exceeds the
number of WiFi hotpoints, they have the same transmit power, and
they are located closer to people.

Bottom line: whatever risk there is to the public is much greater
from mobile phones than from WiFi.

If the objective is to reduce harm to the public from 5 GHz
radiation, the greatest result will come from outlawing
mobile telephones. If the harm (whatever it is) from mobile
phones is acceptable, then the vastly smaller harm from WiFi
is /de minimis/

--
| The brighter the stupid burns, the more |
| chance that someone will see the light. |
+- D. C. Sessions <(E-Mail Removed)> -+
 
Reply With Quote
 
Bert Hyman
Guest
Posts: n/a

 
      09-25-2008, 02:59 PM
(E-Mail Removed) (D. C. Sessions) wrote in
news:nqksq5-(E-Mail Removed):

> Penang wrote:
>
>> Is there any _PROVEN_ harmful effect stemming from the wireless
>> radiation of WIFI, be it in the 2.4GHz band (for 802.11b and
>> 802.11g) and in the 5GHz band (for 802.11n) ?
>>
>> Although I am part of the team deploying the city-wide wifi
>> coverage, I want to be sure that what I am doing would NOT cause
>> any harmful effect to the people of this city.

>
> The frequencies used for WiFi are the same as those used for mobile
> telephones.


Not really. Phones generally operate in two bands, 800-900Mhz and
1800-1900Mhz. These numbers are vague enough to cover the US and the
rest of the world, and GSM and whatever they call the CDMA services
popular in the US. The data services are often elsewhere, but not at
2.4GHz or 5GHz, so far as I know.

> The number of telephones obviously *vastly* exceeds the number of
> WiFi hotpoints, they have the same transmit power, and they are
> located closer to people.


But WiFi APs and computer WiFi NICs radiate continuously, while phones
will transmit only while in a call, or make periodic short
transmissions while inactive. Radiation from a cell transmitters will
probably be continuous though.

As to proximity, your PC's NIC might be sitting on your lap, and
depending on where you are, the AP might be hanging on the ceiling,
directly overhead.

All that said, I have no reluctance to carry a cellphone in my pocket
or use it whenever I need to, nor to use my WiFi equipped laptop for
hours at a time.

--
Bert Hyman | St. Paul, MN | (E-Mail Removed)
 
Reply With Quote
 
Gregory Weston
Guest
Posts: n/a

 
      09-25-2008, 03:53 PM
In article <(E-Mail Removed)>,
Jeff Liebermann <(E-Mail Removed)> wrote:

> On Wed, 24 Sep 2008 21:38:19 -0700 (PDT), Penang <(E-Mail Removed)>
> wrote:
>
> >Is there any _PROVEN_ harmful effect stemming from the wireless
> >radiation of WIFI, be it in the 2.4GHz band (for 802.11b and 802.11g)
> >and in the 5GHz band (for 802.11n) ?

>
> Not that I've seen. The logic parallels the cell phone causes cancer
> logic. Note that PCS band cellular handsets operate at 1800/1900MHz,
> which is close enough to 2.4GHz to have similar biological effects. I
> think I have a suitable defense that you might try using.
>
> In the US, the incidence of new brain cancer cases is commonly
> available and almost flat. Meanwhile cell phone use has increased
> exponentially. If there were any connection between cell phone use
> and brain cancer, one would expect the brain cancer incidence trend
> line to follow the cell phone usage trend line.


Eventually. Not at a lag of a month, or a year or even 5 years.

> It doesn't.
>
> I covered the issues and numbers previously in:
> <http://groups.google.com/group/alt.internet.wireless/msg/fd25bae4b3f10c13>
>
> The traditional counter arguments is that biological damage from RF
> takes more time to appear. We've had commodity cell phones for 20
> years.


No we haven't. 20 years ago cell phones were expensive and rare. They
certainly weren't strapped to the heads of 3/4 of the under-30 populace
as they seem to be now. I saw something within the last month indicating
that the waves penetrate further the younger you are. As such the data
available based on occasional use by a relative handful of 40-year-olds
in the late 80s aren't necessarily applicable to the near-routine use
among teens and preteens today.

I'm *not* saying that the alarmists are right. But I will say it's too
early to be completely dismissive of concerns they try to raise.

> How long are we suppose to wait?


How long does cancer take to develop detectably? Depends on the cancer,
but the window is typically measured in decades.

G

--
"Harry?" Ron's voice was a mere whisper. "Do you smell something ... burning?"
- Harry Potter and the Odor of the Phoenix
 
Reply With Quote
 
 
 
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wifi walls effect on Broadband ? Marky Broadband 4 01-15-2005 07:51 PM
Does weather effect Wifi in the home ? Meatwad Wireless Internet 10 08-07-2004 06:24 PM
WLAN radiation / mobile phone radiation Torgeir Wireless Internet 5 06-05-2004 02:03 PM
Radiation from wireless TV sender harmful? Anon Wireless Internet 43 06-03-2004 07:22 PM
WLAN radiation / mobile phone radiation Torgeir Wireless Internet 0 05-23-2004 04:28 PM



1 2 3 4 5 6 7 8 9 10 11