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Re: Longitudinal Wave Experiment
Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>
Tesla list wrote:
> Original poster: "David Thomson by way of Terry Fritz
> Hi Ed,
> >> There is no doubt at all that longitudinal waves exist on the ground
> >> I would venture further and say that radio waves cannot be detected along
> >> the ground (or at least they will be severely diminished.)
> > Not sure what you mean by that, but ground wave transmission is the
>> normal mode for ALL commercial BC stations.
> I'm talking about the ground plane, not the ground. The ground plane for a
> quarter wave antenna is the surface between the earth and the atmosphere,
> not the earth below the surface. By definition, the ground plane is zero
> volts wrt a resonant quarter wave antenna.
By measurement, its not zero volts. I suggest measuring one.
(Hint: It is common, in some texts, to make simplifying
> >> How many HAM operators do you see trying to receive HF with antennas
>>> lying on the ground?
> > A number of people have used them quite successfully. It's easy,
>> particularly where the soil conductivity is as low as it is in most
>>places on land.
> This isn't the same thing. Lying an antenna on the ground is different
> from burying an antenna or sinking a ground rod. When I say "lying
> an antenna on the ground," I mean literally lying the wire right on
> the surface of the earth. No ground rods, no aerials, nothing is
> buried. The wire is flat on the ground.
On the ground or in the pipe?
> I've put this experiment to a friend of mine. We're going to get
> two 20 foot lengths of 4.5" OD plastic pipe and tape two 40 foot
> long wires to the pipe 4.25" apart. In the middle of these wires we
> will use the half wave of a nearby 1390KHz radio transmitter that
> happens to be in the line of sight from my yard. The long pipes will
> lie directly on the ground and we will be able to turn them to test
> for angular alignment with the radio station.
This arrangement will detect conventional EM.
> A crystal radio will be placed across the two wires in one test to
> see if there is demodulation. Then the pipes will be lifted as
> high as possible to see if there is a change in performance.
Amy good antenna text will discuss the influence of dipole
height over ground.
> I'll also measure voltage at the ground level and at a higher level.
> We will also conduct these measurements with the pipes rotated in
> different angles wrt to the transmitter.
cf above. All done and documented, decades ago.
> I will also cut three metal pipes. One will be 3 times the wavelength
> of the half wave,
3 times the half wave, or three times the wavelength?
roughly, that's 375 meters of pipe, at 1390 KHz...
> one will be three times the length of the full wave,
that's near a km of pipe...
> and one three times the length of pipe where the nodes are spaced
> equal to the half wave of 1390KHz. If there is a longitudinal
> component to this wire arrangement, it will cause these pipes to
> mechanically resonate.
Which will be detected how?
> The purpose of this experiment will be to see if there are any clear
> indications that longitudinal waves are present.