LESSON TWELVE. PRINCIPLES OF WAVE TELEGRAPHY.Wireless Telegraphy as practiced to-day is merely a method of setting up electromagnetic waves in the ether and then detecting their existence at a distant point. It may be divided into four distinct and individual operations, namely:The generation of electrical oscillations.The transformation of electrical oscillations into electrical waves.The transformation of electrical waves into electrical oscillations.The detection of the electrical oscillations.We have already learned how electrical oscillations may be generated by the discharge of a Leyden jar or a condenser. In order to perform the first two operations named above, it is therefore merely necessary to arrange a condenser in such a way that it is most effective.The induction coil or transformer is employed to charge the condenser because the currents of these instruments are much more powerful than those of a static electric machine. The induction coil is connected to a set of batteries and a key so that the periods during which the current is on and off may be controlled at will by the pressure of the fingers.FIG. 27. Diagram of Wireless Transmitter.FIG. 27. Diagram of Wireless Transmitter.The secondary of the coil is connected to a battery of Leyden jars or a condenser. The fact was mentioned above that a certain amount of inductance in the circuit is necessary for the production of electrical oscillations This is furnished, or at least the greater part, by a device called a helix which consists of a coil of heavy wire wound around a suitable framework.The spark discharge takes place across a device called a spark gap.When the key is pressed, the high potential currents of the induction coil charge the Leyden jar or condenser and cause it to discharge through the helix and across the spark gap. High frequency oscillations are immediately created in this part of the circuit. The spark gap, condenser and that part of the helix included, constitute the closed circuit. The electromagnetic waves thrown off by such an oscillatory system would not be very far reaching in their effects because the disturbances would be confined to the immediate neighborhood of the apparatus, so recourse is had to the aerial and ground. The aerial consists of a network of wires elevated high in the air. The ground or earth connection is simply a large metal plate buried in moist earth or thrown into the sea. By connecting the aerial and ground to the helix in the manner shown in Fig. 27, the high frequency currents are caused to surge up and down the aerial system into the ground and create very powerful electromagnetic waves which possess the power of exciting electrical oscillations in another aerial even though it may be located many miles away.The existence of these oscillations is made known to the receiving operator by a device known as a detector, described fully in one of the following lessons.
LESSON TWELVE. PRINCIPLES OF WAVE TELEGRAPHY.Wireless Telegraphy as practiced to-day is merely a method of setting up electromagnetic waves in the ether and then detecting their existence at a distant point. It may be divided into four distinct and individual operations, namely:The generation of electrical oscillations.The transformation of electrical oscillations into electrical waves.The transformation of electrical waves into electrical oscillations.The detection of the electrical oscillations.We have already learned how electrical oscillations may be generated by the discharge of a Leyden jar or a condenser. In order to perform the first two operations named above, it is therefore merely necessary to arrange a condenser in such a way that it is most effective.The induction coil or transformer is employed to charge the condenser because the currents of these instruments are much more powerful than those of a static electric machine. The induction coil is connected to a set of batteries and a key so that the periods during which the current is on and off may be controlled at will by the pressure of the fingers.FIG. 27. Diagram of Wireless Transmitter.FIG. 27. Diagram of Wireless Transmitter.The secondary of the coil is connected to a battery of Leyden jars or a condenser. The fact was mentioned above that a certain amount of inductance in the circuit is necessary for the production of electrical oscillations This is furnished, or at least the greater part, by a device called a helix which consists of a coil of heavy wire wound around a suitable framework.The spark discharge takes place across a device called a spark gap.When the key is pressed, the high potential currents of the induction coil charge the Leyden jar or condenser and cause it to discharge through the helix and across the spark gap. High frequency oscillations are immediately created in this part of the circuit. The spark gap, condenser and that part of the helix included, constitute the closed circuit. The electromagnetic waves thrown off by such an oscillatory system would not be very far reaching in their effects because the disturbances would be confined to the immediate neighborhood of the apparatus, so recourse is had to the aerial and ground. The aerial consists of a network of wires elevated high in the air. The ground or earth connection is simply a large metal plate buried in moist earth or thrown into the sea. By connecting the aerial and ground to the helix in the manner shown in Fig. 27, the high frequency currents are caused to surge up and down the aerial system into the ground and create very powerful electromagnetic waves which possess the power of exciting electrical oscillations in another aerial even though it may be located many miles away.The existence of these oscillations is made known to the receiving operator by a device known as a detector, described fully in one of the following lessons.
LESSON TWELVE. PRINCIPLES OF WAVE TELEGRAPHY.Wireless Telegraphy as practiced to-day is merely a method of setting up electromagnetic waves in the ether and then detecting their existence at a distant point. It may be divided into four distinct and individual operations, namely:The generation of electrical oscillations.The transformation of electrical oscillations into electrical waves.The transformation of electrical waves into electrical oscillations.The detection of the electrical oscillations.We have already learned how electrical oscillations may be generated by the discharge of a Leyden jar or a condenser. In order to perform the first two operations named above, it is therefore merely necessary to arrange a condenser in such a way that it is most effective.The induction coil or transformer is employed to charge the condenser because the currents of these instruments are much more powerful than those of a static electric machine. The induction coil is connected to a set of batteries and a key so that the periods during which the current is on and off may be controlled at will by the pressure of the fingers.FIG. 27. Diagram of Wireless Transmitter.FIG. 27. Diagram of Wireless Transmitter.The secondary of the coil is connected to a battery of Leyden jars or a condenser. The fact was mentioned above that a certain amount of inductance in the circuit is necessary for the production of electrical oscillations This is furnished, or at least the greater part, by a device called a helix which consists of a coil of heavy wire wound around a suitable framework.The spark discharge takes place across a device called a spark gap.When the key is pressed, the high potential currents of the induction coil charge the Leyden jar or condenser and cause it to discharge through the helix and across the spark gap. High frequency oscillations are immediately created in this part of the circuit. The spark gap, condenser and that part of the helix included, constitute the closed circuit. The electromagnetic waves thrown off by such an oscillatory system would not be very far reaching in their effects because the disturbances would be confined to the immediate neighborhood of the apparatus, so recourse is had to the aerial and ground. The aerial consists of a network of wires elevated high in the air. The ground or earth connection is simply a large metal plate buried in moist earth or thrown into the sea. By connecting the aerial and ground to the helix in the manner shown in Fig. 27, the high frequency currents are caused to surge up and down the aerial system into the ground and create very powerful electromagnetic waves which possess the power of exciting electrical oscillations in another aerial even though it may be located many miles away.The existence of these oscillations is made known to the receiving operator by a device known as a detector, described fully in one of the following lessons.
Wireless Telegraphy as practiced to-day is merely a method of setting up electromagnetic waves in the ether and then detecting their existence at a distant point. It may be divided into four distinct and individual operations, namely:
The generation of electrical oscillations.
The transformation of electrical oscillations into electrical waves.
The transformation of electrical waves into electrical oscillations.
The detection of the electrical oscillations.
We have already learned how electrical oscillations may be generated by the discharge of a Leyden jar or a condenser. In order to perform the first two operations named above, it is therefore merely necessary to arrange a condenser in such a way that it is most effective.
The induction coil or transformer is employed to charge the condenser because the currents of these instruments are much more powerful than those of a static electric machine. The induction coil is connected to a set of batteries and a key so that the periods during which the current is on and off may be controlled at will by the pressure of the fingers.
FIG. 27. Diagram of Wireless Transmitter.FIG. 27. Diagram of Wireless Transmitter.
FIG. 27. Diagram of Wireless Transmitter.
The secondary of the coil is connected to a battery of Leyden jars or a condenser. The fact was mentioned above that a certain amount of inductance in the circuit is necessary for the production of electrical oscillations This is furnished, or at least the greater part, by a device called a helix which consists of a coil of heavy wire wound around a suitable framework.
The spark discharge takes place across a device called a spark gap.
When the key is pressed, the high potential currents of the induction coil charge the Leyden jar or condenser and cause it to discharge through the helix and across the spark gap. High frequency oscillations are immediately created in this part of the circuit. The spark gap, condenser and that part of the helix included, constitute the closed circuit. The electromagnetic waves thrown off by such an oscillatory system would not be very far reaching in their effects because the disturbances would be confined to the immediate neighborhood of the apparatus, so recourse is had to the aerial and ground. The aerial consists of a network of wires elevated high in the air. The ground or earth connection is simply a large metal plate buried in moist earth or thrown into the sea. By connecting the aerial and ground to the helix in the manner shown in Fig. 27, the high frequency currents are caused to surge up and down the aerial system into the ground and create very powerful electromagnetic waves which possess the power of exciting electrical oscillations in another aerial even though it may be located many miles away.
The existence of these oscillations is made known to the receiving operator by a device known as a detector, described fully in one of the following lessons.