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RE: [usa-tesla] Vacuum with High Voltage

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  • McGalliard, Frederick B
    A few factors to recall. The face of a CRT is generally much thicker than the side walls. This is to avoid letting soft X-Rays from the high energy electrons
    Message 1 of 94 , Jul 1, 2002
      A few factors to recall. The face of a CRT is generally much thicker than
      the side walls. This is to avoid letting soft X-Rays from the high energy
      electrons into the room, and also to avoid shattering the tube during user
      impacts. The tube also contains a chemical getter that will absorb gas
      during normal operation. I would be a bit careful about handling or spending
      much time near a fully evacuated tube driven by a tesla. The voltage is high
      enough to make X-Rays, and the tube sidewall may not stop them all. This
      tube should be a pretty hard vacuum, so when you get a glow out of it, it
      should come from the electrons bombarding the glass tube wall rather than
      gas in the tube. The streamers suggest gas discharge in the tube, but after
      a while the getter may have pumped it back down where it should be and you
      get a general blue glow from the irradiated glass. If you have a good X-Ray
      detector for soft X-Rays, you might want to check that. Also, if there is
      still gas in the tube, you should be able to identify an emission spectrum
      with well defined spectral lines. You should be able to make the beam squirm
      with a magnetic field. If you put aluminum foil on the end of the side wall
      and grounded it, you might get a nice little acceleration for the beam. An
      axial magnetic field would send the beam down to the end of the tube and
      make a nice bright target point. Worth a try anyway.

      -----Original Message-----
      From: David Thomson [mailto:dave@...]
      Sent: Saturday, June 29, 2002 5:18 PM
      To: usa-tesla@yahoogroups.com
      Subject: [usa-tesla] Vacuum with High Voltage


      Hi Jim,

      I have conducted an experiment today with a cathode ray tube and a Tesla
      coil. I have an Amperex 55261 cathode ray tube that was in like new
      condition when I started. I put a wire between the terminal of the Tesla
      coil and CRT and fired up the coil. At first, there were actual streamers
      inside the CRT. For a while an electron beam formed and illuminated the
      screen with a dot.

      After about a couple minutes the CRT grew bright and then it looked as
      nothing were happening, then the tube changed to a purple glow, just like a
      vacuum tube for a high voltage medical oscillator. After the tube had
      turned purple, it always started off purple with each successive attempt.

      This is similar to Tesla's description of his method for evacuating a vacuum
      tube.

      I noticed that holding a fluorescent tube in various positions around the
      CRT while it was connected to the live coil, that the current in the static
      discharge was strongest around the sides of the CRT and not in front of it
      as I had expected. I'm going to experiment with this some more when it gets
      dark out to see if I'm missing anything. I'll try to get a picture with my
      digital camera and post it, too.

      Dave





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    • Ed Phillips
      ... Excellent thought and way to prove the issue forever. However, I d suggest an experiment where the relative power in the hertzian wave and the other wave
      Message 94 of 94 , Jul 5, 2002
        McGalliard, Frederick B wrote:
        >
        > So if there is such a thing as this non hertzian wave, a simple experiment
        > should show it's existence and characteristics quite nicely, using 1900
        > vintage electronics. No reasonable person would accept the idea of these
        > waves without the proof of principal demonstration. And no reasonable person
        > would fail to accept it with a proof of principal demonstration working on
        > his own work bench. So why are we discussing this? Show Me The POP! Lacking
        > that one little thing, I am afraid that all the discussion about what Tesla
        > said or thought about the waves he was using (or what we may think or not at
        > this late remove) seems rather obscure. Let's pretend I believe these waves
        > exist. How can I prove it?

        Excellent thought and way to prove the issue forever. However, I'd
        suggest an experiment where the relative power in the hertzian wave and
        the other wave be measured at a distance of at least a wavelength at the
        operating frequency, rather than on the bench where there's a lot of
        possibility of stray pickup. Should be a reasonable amount of power
        transmitted, say 100 watts; if Tesla is right the power at a distance
        should be very close to that. Remember, though, that for proof to be
        established the circuits and construction of the transmitter and
        receiver should conform to the drawings in his patents and papers.

        Ever since I first read about Tesla's "longitudinal waves" I've
        wondered whether he isn't being misunderstood. Hertz always used
        ungrounded dipole radiators; Marconi (and presumably Tesla) made his
        stuff work by introducing a ground and an elevated antenna. The
        wireless stations shown in all of his drawings are of that
        configuration. Perhaps by "longitudinal wave" he meant the
        vertically-polarized ground wave which such an antenna would produce.
        At long distance this would have been a "hertzian" wave, but close to
        the transmitter (wavelength over 2 pi or less) there would also be a
        significant magnetic field as well. Just a thought.

        Ed
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