US897279A - Means for generating high-frequency electric oscillations. - Google Patents

Description

PATENTEI) SEPT. 1

R. A. PESSENDEN. MEANS FOR GENERATING HIGH FREQUENCY ELECTRIC OSCILLATIONS.

APPLICATION FILED DEC.17, 1906.

REGINALD A. FESSENDEN, 01* WASHINGTON, DISTRICT OF COLUMBIA.

MEANS FOR GENERATING HIGH-FREQUENCY ELECTRIC OSCILLATIONS.

Specification of Letters Patent.

Patented Sept. 1, 1908.

Application filed December 17, 1906. Serial No. 348,194.

To all whom it may concern."

Be it known that I, REGINALD A. FESSEN- DEN, citizen of the United States, and resident of Washington, in the District of Columbia, have invented certain new and useful Improvements in the Means for Generating High- Frequency Electric Oscillations, of which the following is a specification.

My invention relates to the generation of high frequency oscillations and more particularly to thetransmission of energy by electromagnetic waves and still more particularly to means for transmitting signals by electromagnetic waves.

In the accompanying drawings forming a part of this specification Figure 1 illustrates apparatus whereby the high frequency electrical oscillations are generated. Figs. 2 and 3 show sending arrangements for electromagnetic wave signaling. Fig. 4 is a detail drawing showing the method in which the terminals of the apparatus shown in Fig. 1 are made. Fig. 5 shows the method of introducirng conductors into the chamber shown in Elihu Thomson, (U. S. Patent 500,630, 1893) disclosed means for generating high frequency oscillations by means of an arc and an induqtance. It was found that this method could not be applied to wireless telegraphy, as neither constant frequency nor intensity could be obtained and the arc would not restart itself.

By my improved devices the discharge is made so regularly and uniformly that it can readily be employed in telephony, etc.

In Fig. 1, 1 is a chamber inclosing electrodes and containing compressed gas preferably nitrogen. This is obtained by pumping compressed air into the chamber through the pipe 2 and causing a discharge to pass between the terminals 3, 4 so that the oxygen combines to form nitrous acid which is absorbed by a quantity of lime 5 placed in the chamber. I

6 is a pressure gage. Placed near the sparking terminals or electrodes are magnets 7 and 8 excited by the coils 9 and 10. The electrodes 3 and 4 are hollow tubes and their ends are constructed out of very thin sheet metal. The terminal ends are shown in detail in Fig. 4 where 11 is a piece of thin sheet metal, a few hundredths of an inch thick or less, clamped to the tube 3 by the ring 12. The thin metal tips are cooled by water which is forced at a considerable velocity through the pipes 13 and 16 and issues through the outer tubes by the pipes 14 and 15.

Fig. 2 shows the arrangement connected up for use, 16 being a source of continuous current preferably of constant voltage, such as a storage battery, 17 bcinganadjustable inductance having a high resistance, 18 being a capacity and 19 the primary and 20 the secondary of a transformer.

21 is the aerial which is connected to the secondary of the transformer and grounded at 22.

' 23 is a telephone transmitter.

24 is the discharge gap shown in detail in Fig. 1.

In the operation of the device the con tinuous source of voltage16 charges the condenser 18, through the resistance 1.7, and on the discharge passing across the terminals 3 and 4 of the discharge gap the condenser 18 is discharged and is then charged again through the resistance 17, this process going on continuously and'automatically.

In Fig. 3 the discharge gap 24 is connected directly to the aerial 22, 18 being as before the condenser, 19 an inductance, 17 a variable resistancc, 25 a source of voltage, 23 a telephone transmitter.

On talking into the transmitter 23, Fig. 2 or 3, the emission of the electromagnetic waves is altered corresponding to the speech.

In Fig. 5, 26 is the wall of the chamber shown in Fig. 1, 27 and 28 are hard rubber pieces, 29 and 30 are terminals. The advan tage of this form ofconnection is that no soldered joints are required and the connection is positive between wire and wire.

In the operation of the discharge gap shown in Fig. 1, the terminals b being made of extremely thin metal are coo ed more efficiently. Moreover it is found that by the use of extremely thin metal strips there is no wearing away of the electrodes and the frequency of intensity remains constant. This renders it more suitable for tele honic work. Moreover the discharge instea( of being an are, "l. c. instead of the current being carried by metallic vapors is carried by the gas ontirely and it is of great advantage, having been described by Cooper-Hewitt and by the applicant. It is, however, novel to use such thin metal electrodes as to prevent the cur-,

rent being carried at all by the material of the electrodes being vaporized.

I have found that the metal to be used for the terminals depends upon the character of the gas, aluminum being better suited, for example in hydrogen while silver and copper are better suit-ed in oxygen and nitrogen.

\Vhat 1 claim is:

1. In apparatus for generating high frequency oscillations, a pair of s ark gap terminals, one of which termina s is made of very thin sheet metal, and means to keep said terminal cool.

2. In apparatus for generating high frequency oscillations, a pair of terminals, an inclosing non-vacuous chamber, and the terminals being made of very thin sheet metal, and having means to keep them cool.

3. A discharge gap comprising two hollow metallic terminals with very thin walls at their ends, means to keep said walls cool, and a chamber of gas surrounding the terminals and adapted in connection with the cooling, to keep the terminals from vaporizing.

sure, and the terminals being made of very I thin sheet metal and having means to keep them cool.

Signed at Brant Rock in the county of Plymouth and State of Massachusetts this 15th day of December A. l). .1 J06.

REGINALD A. FICSSIGNDEN.

\Vitnesses:

ADELEINE Womcwnn, Jnssim E. Bnx'r

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