Improvements in Apparatus Employed in Wireless Telegraphy.
Year: 1899

page_text: Date of Application, 15th Mar., 1899
Complete Specification Left, 13th Dec., 1899-Accepted, 17th Feb., 1900
PROVISIONAL SPECIFICATION.
Improvements in Apparatus Employed in Wireless Telegraphy.
We, GUGLIELMO MARCONI, Electrician, and THE WIRELESS TELEGRAPH AND
SIGNAL COMPANY LIMITED, both of 28, Mark Lane, in the City of London, do
hereby declare the nature of this invention to be as follows:-
In the Specification of a former Patent, No. 12039 of 1896, an arrangement is
described in which the transmitter consisted of a sparking appliance having one
terminal connected to an insulated conductor in the air, and the other terminal
to earth, whilst the receiver contained a sensitive tube or sensitive imperfect
contact, having one end connected to a similar conductor, and the other end to
earth.
It is found that the aerial conductor sometimes becomes charged with atmos-
pheric electricity, and when the same conductor is used both for transmitting
and receiving, this electricity discharges through the operator when he shifts
the conductor from the transmitter to the receiver, or through the imperfect
contact when the conductor is shifted from one instrument to the other, and this
is liable to give a shock to the operator, or to injure the imperfect contact. The
object of this invention is to remove this inconvenience, and also to render it
impossible for the operator to accidentally operate his transmitter, and thereby
cause a spark when the aerial conductor at his station is connected to the
receiver, which might injure the imperfect contact.
According to this invention, the aerial conductor is permanently connected to
one terminal of the sparking appliance and, therefore, if a Ruhmkorff coil or
transformer is used, the aerial conductor will be connected to earth through its
secondary winding, thus preventing the accumulation of atmospheric electricity
in it, whilst it is found that the electrical oscillations falling upon it from the
transmitter of the correspondent station cannot readily traverse the convolutions
of the coil, but prefer to pass to earth through the receiver, when the said aerial
wire is connected to it. It is also found advantageous to insert an impedance
coil between the terminal of the induction coil used for sending, and the sphere
which is connected to the aerial conductor. The signals are sent as before by
means of a Morse key in a local battery circuit, through the primary of the
Ruhmkorff coil or transformer.
According to this invention, the arm of the key is prolonged beyond its pivot
and carries an insulated terminal, which is permanently connected to the ter-
minal of the sparking appliance, and therefore to the aerial conductor. Below
this terminal there is, on the base of the instrument, the terminal of the receiver
The arm is so arranged that immediately it is released by the operator, after
sending a message, it turns about on its pivot, bringing the above-mentioned
conductors together, thus connecting the receiver to the aerial conductor. The
wire connecting the receiver to the terminal on the base of the key should
preferably be enclosed in a metal tube to protect it from the oscillations of the
local transmitter.
I
!

page_text: This invention is also applicable if the earth connection is substituted by a
capacity area. In this case, the capacities of the transmitter and receiver should
preferably be connected together. In place of actually connecting the aerial
conductor to the terminal of the sparking appliance it may be led in close
proximity to it.
This invention can also be applied to receivers containing an induction coil
or transformer as described in the Specification No. 12326 of 1898. The means
adopted for protecting the receiver are preferably those described in the Specifi-
cation No. 12325 of 1898.
We, GUGLIELMO MARCONI, Electrician, and THE WIRELESS TELEGRAPH AND
SIGNAL COMPANY LIMITED, both of 28, Mark Lane, in the City of London, 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;-
-
In the Specification of a former Patent, No. 12039 of 1896, an arrangement is
described in which the transmitter consisted of a sparking appliance having one
terminal connected to an insulated conductor in the air, and the other terininal
to earth, whilst the receiver contained a sensitive tube or sensitive imperfect
contact, having one end connected to a similar conductor, and the other end to
earth.
It is found that the aerial conductor sometimes becomes charged with atmos-
pheric electricity, and when the same conductor is used both for transmitting
and receiving, this electricity discharges through the operator when he shifts
the conductor from the transmitter to the receiver, or through the imperfect
contact when the conductor is shifted from one instrument to the other, and this
is liable to give a shock to the operator, or to injure the imperfect contact. The
object of this invention is to remove this inconvenience, and also to render it
impossible for the operator to accidentally operate his transmitter, and thereby
cause a spark when the aerial conductor at his station is connected to the
receiver, which might injure the imperfect contact.
According to this invention, the aerial conductor is permanently connected to
one terminal of the sparking appliance and, therefore, if a Ruhmkorff coil or
transformer is used, the aerial conductor will be connected to earth through its
secondary winding, thus preventing the accumulation of atmospheric electricity
in it, whilst it is found that the electrical oscillations falling upon it from the
transmitter of the correspondent station cannot readily traverse the convolutions
of the coil, but prefer to pass to earth through the receiver, when the said aerial
wire is connected to it. The signals are sent as before by means of a Morse key
in a local battery circuit, through the primary of the Kuhmkorff coil or trans-
former,

page_text: According to this invention, the arm of the key is prolonged beyond its pivot
and carries an insulated terminal, which is permanently connected to the ter-
minal of the sparking appliance, and therefore to the aerial conductor. Below
this terminal there is, ou the base of the instrument, the terminal of the receiver.
The arm is so arranged that immediately it is released by the operator, after
sending a message, it turns about on its pivot, bringing the above-mentioned
conductors together, thus connecting the receiver to the aerial conductor. The
wire connecting the receiver to the terminal on the base of the key should
preferably be enclosed in a metal tube connected to the box containing the
receiver to protect it from the oscillations of the local transmitter.
This invention is also applicable if the earth connection is substituted by a
capacity area. In this case, the capacities of the transmitter and receiver should
preferably be connected together.
This invention can also be applied to receivers containing an induction coil
or transformer as described in the Specification No. 12326 of 1898. The means
adopted for protecting the receiver are preferably those described in the Specifi-
cation No. 12325 of 1898.
The drawing is a diagram of a combined transmitting and receiving station
arranged in accordance with this invention.
is a battery, and an ordinary Morse key closing the circuit through the
primary of an induction coile the terminals of the secondary being connected to
spheres or conductors e between which the spark takes place.
The aerial conductor is permanently connected to one of the spheres & the
other being connected to earth E. The key 6 has two contacts insulated
from each other. The diagram shows the key in the position for sending the
contact 6 touching the contact b and closing the circuit of the battery a through
the primary of the induction coil c. Immediately the key is released by the
operator its longer arm falls by its own weight the contact descending onto
the contact which is connected to the receiver R by the wire M.
The space between the contacts and 6³ must be large enough to prevent
sparking between them.
It is found advantageous to insert an impedance coil d between the terminal of
the induction coil used for sending and the sphere which is connected to the
aerial conductor.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. The combination of an aerial conductor permanently connected to a capacity
which may be the earth through the secondary of the spark producer of the
transmitting instrument with means for connecting it to the receiving instru-
ment.
2. A key having two contacts insulated from each other one connected to the
aerial conductor and the other to one terminal of the primary of the spark
producer these contacts engaging with contacts connected respectively to the
receiving instrument and to the other terminal of the spark producer.
3. Apparatus employed in wireless telegraphy substantially as described and
illustrated in the drawings.