Tuesday, February 10, 2015

RF Effects from Cellular Phones versus Tower Antennas



People who do some reading on the subject come across concerns about exposure to cellular energy, and the tendency  is to equate  this as a concern over the antennas on the tower. The reality is that if there is any RF safety  concern  related  phone systems , it is with using the phone itself , not with the energy from  the antennas  on the tower.  The only exception is if anybody  on  the  tower to one or more  of the antennas.
Here are  two statements  that apply to every tower site with cellular antennas :
1. If  anybody hold a cell phone  near ones  head , as opposed to texting, using a headset , or a hands free device , one will absorb an absolute minimum  of 100 times more of RF energy than the maximum  one  could absorb from any tower-mounted  cellular antennas , assuming one  on the ground.
2. If cellular  reception is poor  in ones area , the installation of a cellular  tower or cellular antennas on a roof top / water tank will dramatically  reduce the RF exposure of any one that uses a cellular phone in handhold mode.
Cell phones are programmed to use the minimum  amount of power needed to make good connection. So, when the signal is strong  the phone transmits at no more than 10 % of the power that it uses when the signal is weak.  And when the connection  is poor, people tend to hold the  phone tightly to their  heads so that they can hear better , which further increases their exposure by another factor of 10. So, when a person holding a phone tight to his or her  head with a poor connection will absorb at least 100 times RF energy  than when the phone is held about an one inch away and the signal is strong.
The other point is that children tend to not  use  headsets . For this reason there are restrictions on the use of cellular phones by children in Great Britain. One study showed that children under 20  who use  cellular phones  are five times more likely to get brain cancer than children who do not use cellular phones.

More in next blog.
 Kisalay Mitra ,
 EFCTN .

Tuesday, February 3, 2015

RF Energy and the Human Body



Much of the confusion  and  concern  over exposure to RF energy comes from confusion over the two forms of radiation that people might encounter.
Think Hiroshima , Nagasaki , Chernobyl , X-rays , and Uranium  and everybody gets concerned . Radioactive materials and X-rays  generate  what is known as  ionizing radiation  , which can be very dangerous ionizing radiation  kills  or damage human cells , its effects are cumulative  and there is no practical minimum . So , continuous exposure to low levels of ionizing radiation can eventually lead to serious health problems. Just getting an x- ray kills or damage millions of  cells in our body. But our body will repair itself   within short period , providing there is no additional exposure . However , the person  giving you the X-ray has to be very careful to get behind  the lead in the door so that they don't get exposed. This exposure  would be repetitive and cause  cumulative  effects.
In contrast, radio frequency energy and the energy from most of the light frequencies are forms of  non-ionizing radiation. This form of energy can heat  tissue  when it is concentrated enough and is the principle behind  the common microwave oven. Exposure to  very tiny amounts of RF energy has much less impact on us  than if  the temperature in the room we are in were to change by a small  fraction to over exertion  degree. Problems occur.
of a  with exposure to RF energy only when it is so concentrated that our body has a problem dealing with the excess heat. The effects are very similar .
K Mitra 
more next blog
EFCTN