Improvements in Wireless Telegraphy.
Year: 1899

page_text: Improvements in Wireless Telegraphy.
I, FERDINAND BRAUN, Professor and Doctor of Philosophy at 1, Universitats
Strasse, Strassburg, in Alsace, German Empire, do hereby declare the nature
of this invention to be as follows:-
It has already been proposed in wireless telegraphy to attach a large metal
plate to the receiving wire with the object of strengthening the action thereby.
But in the same degree as (under the most favourable conditions) the absolute
quantity of electricity intercepted is increased, the surface to be charged is
also correspondingly increased, so that the increase of potential on which the
excitation of the colerer specially depends is not thereby altered. In conformity
with this conclusion experiments have shewn that the improvement is practically
unimportant.
The following arrangement avoids this defect.
A number of parallel wires, as thin as possible, are stretched crosswise,
parallel to the direction of the electric vibrations of the transmitter: they are
united in one point and this point is connected to the coherer. Herein use is
made of the discovery that the electro-static lines of magnetic force as well as
the dielectric displacing currents when in the neighbourhood of conductors
tend to draw towards them. In this manner practically the entire electrical
energy of the induction falling on the surface is intercepted, whilst the capacity
is very small. The potentials are therefore high and the reaction favourable,
as proved by experiment. The wires can of course be distributed as on a
cylindrical surface.
The electro-dynamic reactions which occur in the single wires are hereby
obviously increased only with regard to the free charges thus produced and as
soon as their quantity is sufficient for the capacity of the coherer and the
neighbouring surface to be charged, then practically the limit of the reaction
is reached.
In order also to sum up the induced electromotive forces, the wires must
be connected in series. This may be carried out in the following way. Between
the front and back wires and insulated from them a sheet of metal is inserted.
This protects the back wires from direct induction and they then serve essentially
only as conducting wires in order to sum up the electro motive forces induced
in the front ones. The same object can be attained by protecting the leading
off wires by surrounding metal (say in the shape of a tube).
The metal sheet may in practise be replaced by wire gauze and there is
even some action if it is quite absent as the front wires themselves partially
screen the back ones if suitably placed.
The same object may be attained by inserting between the front and rear

page_text: intercepting wires a length of wire or a device acting by induction or capacity,
or both, in such a way that it produces a difference of path of half a wave
length.
Both arrangements may also be combined.
It is also possible to make the transmitter out of two crossed systems insulated
from each other and to form the receiver in the same way taking care of favour-
able conditions of capacity. The horizontally polarised waves pass through
the vertical wires or rods and vice versa. The advantage lies in being able to
regulate the capacity and in the symmetry of arrangement and compactness
within a small space which renders possible a metallic protection against un-
expected interruptions.
The current collected from the frame can also be conveyed to a small primary
coil and transformed in a secondary coil to greater potential, and then the
coherer be excited thereby.
Moreover two metal balls, which are in so intimate contact with each other
as the particles of a coherer can be inserted in the intercepting wire the quick
oscillations produced thereby are conducted to the coherer. This may be of
advantage in dealing with very slow waves.
The transmitter and receiver, or one of them, can also consist of plate coils
or of solenoids of the usual form.
Dated the 14th day of June 1899.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.
I, FERDINAND BRAUN, Professor and Doctor of Philosophy, of No. 1, Universität
Strasse, Strasburg, in the Alsace, German Empire, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
;--
It has already been proposed in wireless telegraphy to attach a large metal
plate to the receiving wire with the object of strengthening the action thereby.
But in the same degree as (under the most favourable conditions) the absolute
quantity of electricity intercepted is increased, the surface to be charged is
also correspondingly increased, so that the increase of potential on which the
excitation of the coherer specially depends is not thereby arrived at.
In con-
formity with this conclusion experiments have shown that this arrangement
is practically useless.
The following arrangement is intended to obviate this defect.
This invention is shown by the figures (1-10), which are diagrams of the
arrangements and the electrical connections, similar reference letters being
provided for similar parts.
A number of parallel wires, as thin as possible, a¹, a², a³ and so forth are
stretched as to form a grating parallel to the direction of the electric vibrations
of the transmitter: they are connected to the coherer (by means of a common
connecting wire. Herein use is made of the discovery that the electro-static
lines of force aus well as the dielectric displacement currents when
in the neighbourhood of conductors tend to come nearer to one another. In
this manner practically the entire electric energy of the induction falling on
the surface, is intercepted, whilst the capacity is very small. The potentials

page_text: are therefore high and the reaction favourable, as proved by experiment. The
wire can of course be distributed as on a cylindrical surface.
Fig. 2 shews a symmetrical arrangement; K is a condenser, C the coherer,
the action of these elements being so well known as to need no further
description.
The electro-dynamic reactions which occur in the single wires are hereby
obviously increased only with regard to the free charges thus produced and as
soon as their quantity is sufficient for the capacity of the colerer and the
neighbouring surface to be charged, then practically the limit of the reaction
is reached.
In order also to sum up the induced electro-motive forces, the wires must be
connected in series. But doing so, as indicated in Fig. 3, then one would come
to no result because, it in the front wires a¹, and so forth turned towards
the transmitter, currents in the upward direction were induced then the same
amount of potential would be produced in the wires a, a, and so forth, on
the other side of the grating but in the opposite sense, and therefore the wind-
ings would neutralise one another. The following arrangement (Fig. 4) avoids
this defect. Between the front and back wires and insulated from them a sheet
of metal is inserted. This protects the back wires from direct induction so
as to to make them serve essentially only as conducting wires in order to sum
up the electro-motive forces induced in the front side. The same object can
be attained by protecting the leading off wires by surrounding metal (say in
the shape of a tube).
The metal sheet may in practise be replaced by wire gauze and there is even
some action if it is quite absent as the front wires themselves partially screen
the back ones if suitably placed.
Finally the same object may be attained as indicated in Fig. 5. When
between front and back intercepting wires a length of wire is operatively con-
nected by means of induction or capacity or both, which wire is of such a length
as to produce a difference of course of half a wave length.
Fig. 6 shews a combination of the two arrangements.
Fig. asymmetrical arrangement; K is a condenser, C the correspond-
ing tube.
It is also possible to make the transmitter out of two systems of grating
arranged crosswise and insulated from each other (Fig. S) and to form the
receiver in the same way having regard to favourable conditions of capacity.
The horizontally polarised waves pass through the vertical wires or rods and
The advantage lies in the possibility of regulating the capacity and
the symmetry of arrangement and compactness within a small space which
rendeis possible a metallic protection against unexpected disturbance.
rice versa.
The current collected from the frame can also be conveyed to a small primary
coil I and transformed in a secondary coil II to greater potential, and then
the coherer be excited thereby.
Moreover two metal balls S1, S2 can be inserted in the intercepting wire
especially in dealing with the interior of a coherer, and the quick oscillations
produced thereby are conducted to the coherer.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. An intercepting apparatus for telegraphy by electrical waves consisting
of a system of parallel wires for the incoming electrical vibrations, which wires
may be connected either in parallel or in series, substantially as described.
2. The special arrangement of arranging the wires in two planes lying one
behind the other between which planes is placed a metal plate or a lattice,
substantially as described.
3. Connections between the wires devised by means of resistance, capacity or

page_text: self induction to displace the phase of the front set of wires half a wave length
against the back set, substantially as described.
4. Two gratings of wire crossing each other at right angles and one lying
behind the other, substantially as described.
Dated the 13th day of March 1900
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.