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Re: Any Very High Freq. TCs?

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 ?

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.

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!

Well, all I can say here is, "I am not sure". But I welcome any input
from you guys.

Louis




> From tesla-request-at-pupman-dot-com Fri Sep  4 13:17 BST 1998
> Resent-Date: Fri, 4 Sep 1998 06:05:36 -0600
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> Date: Thu, 03 Sep 1998 22:03:42 -0600
> To: tesla-at-pupman-dot-com
> Subject: Re: Any Very High Freq. TCs?
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> From: Tesla List <tesla-at-pupman-dot-com>
> 
> Original Poster: Richard Hull <rhull-at-richmond.infi-dot-net> 
> 
> 
> 
> Tesla List wrote:
> 
> > Original Poster: Julian Green <julian-at-kbss.bt.co.uk>
> >
> > > Original Poster: Steven Ivy <adder_black_the-at-yahoo-dot-com>
> > >
> > snip...
> > > volts at 1 GHz operating on my kitchen table : ) Is there some
> > > particular flaw in this scaling idea other than the difficulty in
> > > producing a spark gap capable of operating at these very high
> > > frequencys.
> >
> > Have you wondered why you get streamers that terminate in thin air?
> >
> > Well I believe that it is due to the capacitance of the air
> > and its ability to ionize forming conductive clouds of gas around
> > the coil.
> >
> > The current in a capacitor rises as the frequency increases.
> > Therefore as the frequency of your tesla coil rises so does
> > the ability of the surrounding air to disipate the high voltage.
> >
> > The result is that as frequency rises the streamers shorten. At
> > about 1MHz you get discharges that look like a gas cooker flame
> > and loads of ozone.  I think Richard Hull has photos if this.
> >
> > If you want long and impressive streamers go for low frequency,
> > around 100KHz.
> >
> > How many turns on the secondary would you need for a 1GHz tesla
> > coil?
> >
> > Julian Green
> 
> Julian and Malcolm echo my sentiments.  Both the capacitance and
> inductance of an HF coil would be so tiny that real resonant rise into
> the MV range just could not occur in air.  Such a power density would
> corona and bristle with losses.
> 
> The CEBAF <continuous electron beam acceleration facility> accelerator
> here in Virginia (most powerful continuous electron accelerator in the
> world) uses super conducting pure niobium resonant cavities and develops
> 6 MEV rise across the waveguide cavity's throat which is ~1" across with
> no arcing.  There are a gang of these cavities in series. along the
> large race track.  The frequency is in the Ghz range, but there is, alas
> no, spark.  It is slightly inhibited due to the entire device being
> under one of the hardest vacuums known to man >10E-10 torr.  This is all
> I can learn.  They are reluctant to release great detail on the ultimate
> vacuum and certain aspects of the liquid helium distribution network.
> 
> The head of engineering at CEBAF and designer of the cavities comes to
> our TCBOR meetings once or twice a year.
> 
> Richard Hull, TCBOR
> 
> 
> 
>