Re: Tesla Coil RF Transmitter

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

HI Dan,

On 12 Sep 2005, at 19:46, Tesla list wrote:

> Original poster: "Dan" <DUllfig@xxxxxxxxxxxxx>
>
> Your contention that the current needs a two way path is, i believe,
> incorrect. That would be true for DC currents, but not AC. When the
> current is flowing from the tramsmitter to the receiver, the charge
> accumulates in the top capacitance of the receiver. When the current
> is flowing back, it flows back out of the reciver's capacitance, into
> the transmitters capacitance.

Any current flow can be considered to be in a single direction at
some instant in time. Put another way, at any instant, a current flow
can be considered to be DC. (Y-N)?

Malcolm


> It is analogous to a hydraulic system, where instead of pumping the
> oil always in one direction (you need two hoses to do this), you kept
> pumping the oil back and forth. When you do that, you don't need a
> return hose, because the oil can go into an accumulator at each end.
> Think about it.
>
> Dan
>
> PS.: in common household AC, the neutral is not really a return path
> either, but a terminal to collect all three phases and add them
> together. By definition, being neutral, the neutral does not carry any
> current (beyond the untility pole, that is).
>
>
> ----- Original Message -----
> From: <mailto:tesla@xxxxxxxxxx>Tesla list
> To: <mailto:tesla@xxxxxxxxxx>tesla@xxxxxxxxxx
> Sent: Sunday, September 11, 2005 8:31 PM
> Subject: Re: Tesla Coil RF Transmitter
>
> Original poster: Ed Phillips <<mailto:evp@xxxxxxxxxxx>evp@xxxxxxxxxxx>
>
> "Hi all, this response isn't directed at any one in particular; I just
> have a few observations:
>
> 1 -- the earth is conductive, or we would not be grounding equipment
> in it; 2 -- RF can be conducted thru a conductor, or coax would not
> exist.
>
> and finally,
>
> 3 -- given the above statements, why is it so hard for anyone to
> believe that Tesla was transmitting by conduction through the earth,
> and not propagation through the air?! Just becuase you CAN transmit RF
> through the air, doesn't mean it is the ONLY way to do it."
>
> It is impossible to believe that transmission was solely through the
> earth, as many seem to believe.  Take your example of a coax cable.
> The current flow is through the center conductor with a return path
> through the inside of the outer conductor.  TWO-way circuit!!!  In
> Tesla's case, at least as we interpret it now, the current was to flow
> into the earth from the bottom of the coil.  Period.  No return path.
> No way at all this could work.  I wonder if Tesla is being
> misinterpreted and never intended to say that there was no return path
> for the current carried through the earth.  For sure his patents talk
> of a TWO conductor transmission path, with one conductor being the
> ionized "upper layer" and the other being the ground.  Always TWO
> conductors.  Just read the patents.  When he speaks of "driving
> currents into the ground" that may just be hyperbole.
>
> "And Sam, you said the TC transmits poorly; considering that Tesla was
> lighting up light bulbs with his receivers, seems his coils were
> transmitting just fine..."
>
> No foundation for that statement.  He did indeed light bulbs, probably
> through inductive or capacitive coupling (unless you believe the stuff
> about lighting many bulbs many miles a way, a statement with no proof
> at all and apparently invented after his time).  However, he never
> even mentioned how much power was transmitted or being wasted.
> Probably most of it was wasted.  Efficiency was probably nil.
>
> "Some of his earlier experiments involved running a loop of cable
> around his laboratory. He would run RF through it, and light up
> special bulbs anywhere in his lab. He was constantly running
> experiments, probably hundreds of them by the time he was through. If
> his transmitters acutally needed an Aerial, don't you think he would
> have figured that out? why would he drop the earlier aerial (say that
> really quick three times :) in favor of a capacitive top load, if it
> performed worse? It's not like he never tried an antenna!"
>
> That was simple inductive coupling and not transmission.  No mystery,
> no miracle, no significant technical accomplishment except for the
> high frequency involved and his method of generating it.  You can do
> it just as well as he did and the results will be just as good.
>
> Ed
>
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