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Re: Any Very High Freq. TCs?
Tesla List wrote:
>
> Original Poster: W Y Liu <eenwyl-at-sun.leeds.ac.uk>
>
> 1 Ghz signal will certainly suffer from the transmission loss
> in air. Well, I presume after a mile, the 1kw microwave signal from
> the transmitter will become very small. Am I right ?
The size of the beam is determined by what are essentially diffraction
limited optics considerations. The bigger the antenna, the smaller the
beam width can be. But, at a mile, even with a very large (many meters)
antenna at 1GHz, you probably won't get the power density up high enough
to even feel warm. BTW, your eyes are the most sensitive easily exposed
(close to the surface) part for microwave energy, hence the warning not
to look into a waveguide.
>
> i have one more concern regarding the rf harzard, which i am not sure
> and which i am still investigating. If i understand correctly from a
> biologist, our dna's oscillate naturally at microwave
> frequency band and she did imply in her mail to me that dna's will be
> likely "disintegrated" at microwave frequencies. She also told me that
> the microwave frequencies can potentially cause energy blockages.
Most of the power is absorbed in the water in your cells. I don't know
if DNA could be disrupted, or if that effect would even be noticeable
before other thermal effects. There has been some research on EM
radiation interfering with cellular metabolism (your "energy
blockages"?), but I think it is all "in vitro" and at fairly high
fields.
>
> mobile phone frequencies are around nine megahertz, very close to microwave
> band. In the coming years, the transmission power will likely go up to 1.5
> w.
> If this is true, these 1.5w megahertz signals will go right over our heads!
They are already 3 Watts for mobile phones. The handset phones are
generally only 800 mW, because that is the standard next step down of
the 8 used.