Friday, May 13, 2011

Radiation Pattern of a Cell Tower Antenna

Radiation Pattern from the cell tower Antenna has been drawn for basic understanding of a radiation pattern.

This diagram was mainly used to describe why on a certain building the radiation levels vary from one apartment(say 7th floor) to the apartment above or below (6th and 8th floor) for a building at Khar (West), Mumbai.

The radiation pattern of a cell tower antenna is defined by its lobes. Radiation will be highest from the primary lobes in the horizontal direction. There is also radiation from secondary lobes.As seen in the figure, the readings that will be taken in between the lobes will be much lesser.

As seen in the figure, the radiation will also be high vertically downward from the secondary lobes. This is what most mobile operaters hide or are not aware of in India.


Distance is another critical factor. The power density varies by (1/R2), where R is the distance. People living within 50-300meter radius are in the high radiation zone. The figure below is a study from another country. In the US for example, residential areas generally have amplifiers of 1-2 W each. However in India, at many places even 100 to 200W amplifiers are used and there are clusters of antennas from multiple operators on the roof top of several residential and office premises.


Below is a simulated radiation pattern of a cell tower antenna from Prof. Girish kumar, IIT Bombay.


USHA KIRAN BUILDING - several cancer cases

Through the help of the above typical radiation pattern, let’s analyze the news reported in Mid-day, Mumbai dated Jan. 3, 2010, which stated - “Mumbai's swanky Usha Kiran building says the four cancer cases there could be linked to mobile towers installed on the facing Vijay Apartments”. The picture taken from the Usha Kiran building of the several antennas installed on the seventh floor of Vijay Apartments is shown in Fig. below.


People living in the 6th, 7th and 8th floor in the opposite building will get maximum radiation as they are in the main beam direction. People living on the other floors will receive lesser radiation as beam maxima is reduced considerably as can be observed from vertical radiation pattern. In the horizontal direction again, people living in the front side of the antenna will receive much higher radiation compared to people living in the back side of antenna.

http://www.mid-day.com/news/2010/jan/030110-mobile-tower-cancer-cases-carmichael-road-posh-areas.htm

Recently (as on Jan 2011) two more cancer cases have been reported on the 5th and on the 10th floor.

7 comments:

  1. Hi,

    This is very informative, however, I want to know more about radiation below cellphone towers, especially for the residents living in buildings who have erected cellphone towers on the terraces.

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  2. Dear Anand,
    As seen from the first figure, i.e, according to the radiation pattern of cell tower antenna, radiation also travels vertical downward. We have observed that the levels are generally high on the top 2-3 floors from roof top antennas. However, levels may vary based on the angle and construction material used.

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  3. Dear Neha,

    Thanks for the information. We are looking to buy a house where 6 antennas at 60 mt distance on a building opposite us. We are looking at a house on the 8th floor and its directly opposite our balcony at a distance of 60 mts.

    Is there anything that can be done to negate the radiation ? I read somewhere that there are different ways to do the same.

    Also, what can be done to remove the same legally ?

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    Replies
    1. Dear Rini,

      we can carry out Cell Tower Radiation Measurement Survey at your residence from health point of view followed by a report from Prof. Girish Kumar from IIT Bombay.

      Alternativley, you can check the levels using DETEX 189 - http://neha-wilcom.blogspot.in/2011/12/cell-tower-radiation-detector-detex-189.html which has been designed from health point of view and is simple and easy to use. Cost is Rs 4,950/-

      We have shielding solutions like Film, Curtain and Wall Paper. You can read details at: http://neha-wilcom.blogspot.in/2013/01/screen-saver-save-your-home-from.html

      Our contact details are given below. If you have any queries, please feel free to contact us.

      Regards,
      Neha Kumar

      Nesa Radiation Solutions Pvt. Ltd.
      2nd Floor, Plot No. 31,
      Sector 19C, Vashi
      Navi Mumbai 400 705
      Tel: (022) 41241800 / 9619378318
      Website - www.nesa.co.in
      Email - nesaglobal@gmail.com

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    2. You can go through the following presentation and documents for more information to create public awareness and convince operators to reduce the transmitted power.

      1) Report on Cell Tower Radiation by Prof. Girish Kumar sent to DOT with more than 200 references in the end - http://www.scribd.com/doc/44736879

      2) Presentation on Cell Tower Raidation Hazards by Prof. Girish Kumar, IIT Bombay - http://www.scribd.com/doc/132189401/Cell-Tower-Radiation-Report-by-Prof-Girish-Kumar-Dec-2012

      Regards,
      Neha Kumar
      nesaglobal@gmail.com / info@nesa.co.in

      Delete
  4. Great Article, very informative, thanks!

    ReplyDelete
  5. Hi,

    Thanks a lot for the information. I have one question. If my house is within 50m (assuming the dimensions in above diagram), then am I in the safe range?

    We have a tower in 14 m horizontal distance and about 10 m in height from the ground. I made the basic calculation and observed that our house does not fall in the 5-10 degree vertical range (as it is too close and our roof top barely touches the 10 degree line). This makes me think that our house is safe, am I correct? Please let me know.

    Thanks
    Satya

    ReplyDelete