A cellphone is actually a radio transmitter and receiver. It sends and recieves radio frequency electromagnetic waves. The received signals are fairly low level, so I will concentrate on the signal transmitted from the cellphone.

Cellphones transmit mainly at frequencies of 900, 1800 and 1900 Megahertz (MHz). A microwave oven cooks food using a frequency of 915 MHz or 2450 MHz. In other words, the food is not fussy about what frequency you use, as long as it's in that range, say 900 to 2500 MHz. Which means, cellphones use Microwave Oven frequencies.

A microwave oven puts out a power of about 1000 watts, on average. If you put your head in a microwave oven, it will take about an hour to cook to a nice sizzling crisp.

A cellphone transmits at a power of about 3 watts, and it self adjusts it's power continually to compensate for poor signal paths, up to a maximum of 5 to 7 watts. Not much, but there's a twist...

A microwave oven spreads it's radiation over the whole oven cavity, so that the food is cooked uniformly.

A cellphone has a tiny, array antenna, measuring maybe 2 or 3 cm in length, and it's right next to your ear. So 5 watts of power is radiating into your head into an area of perhaps 3cm by 0.75cm. That's a lot of power when concentrated in such a small area.

The cellphone manufacturers have said that they have put "shields" into their phones to keep radiation risks to a minimum.

If you turn around while making a call, does the call cut out or the audio disappear at any time? No, it doesn't. High frequency radio waves, like light waves, travel in a straight line. If your head got in between the cellphone and the cell transmitter tower, then the signal should be blocked (shielded) by the shield in the phone, as the waves can't bend once they've left the phone.

Which means that those microwaves are going through your head, all the time.

Whenever you're "on the phone," you are being microwaved just like the roast in your microwave oven.

So What Can You Do?

If you've got a handsfree kit, use it if it's practical. Rather don't use bluetooth - it also transmits radiowaves close to your head, albeit at different frequencies and at a lower power.

If your phone has a loudspeaker, switch it on and speak at a distance. The guy on the other side will still hear you perfectly.

Buy phones with a low Specific Absorption Rate (SAR)

Don't let children make long calls. Their soft skulls are much more affected than the hard heads of adults. (See "The Stewart Report.")

Swop ears every minute or so, to give your head time to "cool down" on that side.

Don't hold the phone next to your ear while connecting - this is when it transmits at maximum power.

Avoid making calls in weak reception areas, as the cellphone will boost it's output power to make sure it stays connected.

Keep your conversations short.

Use SMS's whenever possible.

Avoid sleeping with a cellphone under your pillow. Cellphones transmit even when you are not using them, exchanging data and checking signal strength, at regular intervals.

Avoid carrying the cellphone close to your body. This applies especially to the breast pocket of people with heart problems.

Use a landline whenever possible.

Many people have proven health problems from cellphone usage, brain tumors being the most common, followed by loss of memory, impaired brain function, cancer of the salivary glands, and other symptons. Usually these symptons take a few years to surface.

By taking the simple precautions listed above, we can potentially save our lives. Tell your family and friends too. There's a lot of people out there who need to be aware of these facts.