In a detailed analysis of forces involved Curry shows that radiators
with a capacitance of .0053 microfarads operating at 100 KHz with
signal generator output of 200 volts coupled with a biasing potential
of 1000 volts will produce a force from its charge displacement
of 26,500 dynes.
On the receiving side Curry states that the charge gradient can be expected
to attenuate substantially at even moderate distance from the
point of transmission. As an example he notes that if a signal
intensity of 10,600 dynes at the point of transmission is reduced
one billion times the "standing wave of the signal energy
will therefore be charged with a force differential of 1.06 x
10-5 dynes. Each dipole having a capacitance of .0053 microfarads
produces a system capacitance of .00265 microfarads. The voltage
developed in the receiving network is given by
e=square root (F/(C x 107)
which in this case equals .02 volts. As noted "this
is substantially above the minimum requirements of signal intensity
for the detection of electrical signal energies."
With such a great amount of operational detail it would seem that this
design should perform as claimed. The device, however, is not
in widespread use 25 years after the issuing of the patent. This
forces the conclusion that the device did not successfully propagate
signals through the water. Why it would not will be made clear by examining the Tesla design
for wireless communication. It will be shown that the dipole nature
of the radiator and the inability to state the amount of attenuation
over a given distance (it was simply given as a billion times
weaker than the transmitted signal) point to a fundamental misunderstanding
of the nature of electrostatic induction.
The shortcoming of the Curry design for an electrostatic communication
system can be seen in the basic nature relationship existing between
two points of charge.(See Figure 6)
of flux exist between two opposite charges a dipole transmitting
antenna is not needed. Curry proposed a dipole in order to create
a wave of
the proper length to be propagated through the medium. However, in electrostatics
it is not necessary for flux lines to detach and close upon themselves
to propagate an electric field. The field is established by the
flux lines between the two points of charge. Curry misunderstood
the nature of the electrostatic field. Once the field is established,
a change in pressure on the charge will cause a variation in charge
at the other end of the field - a displacement current.
Also, Tesla points out that a dipole is not needed to receive even low
frequency signals in an electrostatic system. Tesla pictured his
receivers with electrodes spaced a quarter wavelength apart but
this was to charge an unpowered receiver as rapidly as possible.
The receiver's capacitor would see maximum voltage changes, and,
thus, would gain sufficient charge to power a device, if the ground
electrodes had such a spacing. If, though,
"the impulses are... are alternating, but sufficiently long
in duration" they can be received by a single electrode that
is turned on and off with the same period as the transmitter.
Because the field's flux lines do not radiate but start at the
transmitter and terminate on the receiver, the receiving structure
does not have to be a specific shape or length.
His patent, then, also describes a through-the-earth, compact ELF communication
system. Today's ELF antenna arrays, by contrast, require hundreds
of square miles for their deployment.
Proof of Principle Test
This method of electrostatic communication can be tested by using a grounded,
resonant electrostatic detector coupled to a standard communications
receiver, encased in RF shielding to receive a signal. For demonstration
purposes a commercial station transmitting on 1.16 MHz at 50KW,
40 miles away from the receiver could be used as the test source.
If the transmitter's antenna is feed at 50ohms impedance, the antenna
The quarter wavelength period for 1.16 MHz is:
P = 1/4f
P = 1/(4)1.16x106
P = 2.16x10-7 sec.
The amount of charge
in the antenna during the quarter period is: