Re: Early TC's w/o topload

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Original poster: <davep@xxxxxxxx>


> I don't know "who" first called it a "topload" but I believe I know  the
> reason for using that name. In radio engineering you often see
> reference to "top-loaded" antennas. These have a plate or network of
> wires attached to the top of the mast to add capacitance and allow a
> shorter antenna mast to be used. The top-loading capacitor is
> sometimes referred to as a topload. Some antennas also have a loading
> inductor at the bottom or in the middle.
>
> Now, the analogy to a Tesla coil seems pretty obvious to me. A Tesla
> coil is just a short vertical antenna with a loading inductor at the
> bottom and a loading capacitance on top, and the antenna mast in
> between is then made shorter and shorter until it's completely gone.  It
> is now near useless as an antenna and radiates practically
> nothing. Instead the input power piles up in the resonator before
> bursting out in the form of enormous voltages and colossal discharges.
>
> If you think of the coil as a modified radio antenna, "topload" is  the
> natural name for whatever you place on top.
  While i cheerfully agree with the analogy, like many analogies,
  there are limits.

  In a philosophical sense, it helps to decide what the
  purpose of a given Tesla Coil system is:
    Sparks?
    High Voltage? (without sparks)
    Energy transfer?

  Each of thse can lead to different optimzations.  I suspect the
  use of toroids/spheres/squished speheres in some sorts of
  Tesla Coil work has as much historical ancestry in the use of
  similar shapes for corona reduction (aka "e field control').
  To the best if my knowledge THIS application predates WWII
  in the power business and the HV (notably van de Graff) work.
  (Yes: vdG sets need 'something' to accumulate charge.  As
  with the 'radio transmitter' analogy, the comparison is partial
  rather than exact.

  My recollection is the the Colrado Springs installation
  included a 15 ft (?) 'Aluminum foil covered sphere', in
  addition to the 'hood'?

  best
  dwp