Re: what frequency do cell phones transmit and can they truly be dangerous

1) At what frequencies do cell phones transmit? There are two types of 
cell phones, regular cell phones which operate at frequencies of 800-900 
MHz and Personal Communications Service (PCS) at 1850-1990 MHz. 

There is a cool picture of this in Bulletin 56 from the Federal 
Communications Commission Office of Engineering and Technology, which you 
can get on the web at 
http://www.fcc.gov/oet/info/documents/bulletins. It is figure 2. 

This bulletin covers electromagentic radiation [the technical name for 
this] from cell phones and many other sources, like power lines, TV 
stations and microwaves. There is also a web page for electromagentic 
radiation at http://www.fcc.gov/oet/rfsafety, but the bulletin explains it 
much better.

2) What is the energy levels that cell phones transmit? I was not able to 
find the actual energies that cell phones are able to transmit (although the 
output power is generally output 1 Watt). The energy that human tissue near the cell phones are allowed to absorb is 
less than 1.6 W/kg averaged over 1 g of tissue. (Putting it another way, 1 g of tissue is allowed to absorb 1.6 mW of energy 
near the cell phone). 

3) Whether the energy coming from cell phones is dangerous is an open 
question. Concerns include cancer and heating of specific body parts (eyes 
and testis, because of limited blood flow).

The way to evaluate this is to compare cancer rates in people who use 
cellular phones to those who do not. The problem with comparing people who 
use cell phones with those who do not is that these two groups of people 
are different. For example, the people who use cell phones might tend to 
live in cities while those who do not might live on farms. People who live 
on farms might have lower rates of cancer because they tend to eat a diet 
that is lower in fats and higher in fruits and vegitables. Then, the 
results showing that people who do not use cell phones have a lower rate 
of cancer have nothing to do with whether people use cell phones, but have 
to do with where they live. The point is, these studies are not so strait 
forward as they seem.

Most of the studies relating to this is from studying energy that comes 
from electrical transformers and power lines near homes. Studies of this 
have not shown an increase in cancer from power lines and transformers, 
but the results are not conclusive. However, if there is an increase in 
cancer from power lines and transformers, the effect is small, and this is 
not a great risk. I have not read anything about studies of cell phones, 
but I think the risk is small. However, because cell phone have not been 
around long, it will be a while before cancers start to show up.  So it 
appears that they do not cause cancer, but we realy do not know yet. Even 
if they do cause cancer, it appears that they will cause only a few cases 
a year. So buttom line is that cell phones are safe, but we cannot be sure 
they are completely safe.

As far are heating of organs, the retina of the eye and testicle are the 
two most vulnerable organs. They are both vulnerable because they do not 
have large blood flows that can remove excess heat from radiation. 
However, this is not a large concern for cell phone usage, because FCC 
rules limit the amount of energy to safe levels.

You asked if cell phones truly can be dangerous. Yes they can. Driving 
while using a cell phone is really dangerous. The rate of people crashing 
cars while driving using cell phones is like 2 or 3 times higher than when 
people are not using cell phones. So if you really are concerned about 
cell phone safety, don't talk and drive. I think far more people will be 
killed in car crashes caused by cell phones than by radiation from cell 
phones. I bring this up so you can put the risks of cell phones in 
perspective. You can get rid of most of the dangers of cell phones by not 
using them when concentration is important, like driving.

As an aside, I add that using cell phones in hospitals is dangerous. The 
ventilators that breathe for really sick patients have been known to be 
reset by the radiation from cell phones. Talk about a dummer.

So my answer is so long. Look on the bright side, the bulletin is even 
longer.