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Publication numberUS827524 A
Publication typeGrant
Publication dateJul 31, 1906
Filing dateJan 2, 1906
Priority dateJan 2, 1906
Publication numberUS 827524 A, US 827524A, US-A-827524, US827524 A, US827524A
InventorsLee De Forest
Original AssigneeLee De Forest
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Wireless-telegraph system.
US 827524 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

No. 827,524. PATENTED JULY 31, 1906. L. DB FOREST.



No- 827,524. PATENTED JULY 31, 1906. L. DB FOREST.






Specification of Letters Patent,

Patented July 31, 1906.

To all whom it may concern.-

Be it known that I, LEE DE Fonhs'r, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement in Wireless-Telegraph Systems, of which the following is a specification. 7

M invention relates to wireless telegraphy and as for its object a system which is rovided with a transmittin and a receiving apparatus, both associate with one antenna, and with means whereby a receiving operator is enabled to cut in uponand interrupt a transmitting operator at another station.

In the drawings, which accompany and form a part of this specification and which illustrate dia ammatically one system of circuits where y my invention may be carried into efiect,Figure 1 represents a wireless-telegraph transmitting and receiving system, and Fig 2 represents a modification of a detail of construction.

Heretofore I have described a wireless-telegraph system which is provided with separate transmitting and receiving antennae at the same station and associated apparatus operated by the transmitting-key w ereby a receiving operator may interrupt the transmission for a distant station; but it is obvious that in certain locations,-for example, on shipboard,-'only one antenna is permissible, and with .the. system which forms the present invention the advantage is arrived at that by means of one antenna, employed alternately for transmitting and receiving, a receiving operator may cut in upon a message wh1ch 1s belng sent from a distant transmlttlng-station.

The system which I shall describe in this a plication for the purpose of more fully dis 0 osing my invention embodies in general the principles set forth in my Iprior patents, although it will be obvious t at m invention may be employed with any ot er suitable system and that it is not limited to the system shown herein.

The conductors A, A, which are uninsulated at the top, being conductively connected by the wire N, constitute the two sides of a receiving-loop antenna, the loop bein closed by the conductors a c L g and --g, respectively. Instead of oundin'g the -receiving system by connectlng the pomt directly to earth as heretofore has een t e practlce in systems of this general Application and January 2.190s. Serial no. 294,098.

'the si es of said loop-antenna.

type, in which one antenna is employed a]- ternately for transmitting and receiving, I find it desirable, and practically necessary, to connect the receiving-ground lead to the antenna directly below the anchor sparkap and above thetransmitting-helix L, so t at said helix lies between the receiver and the earth. I find that the presence'of the helix L in the earth connection 9 b e. LE of the receiving system has practically no effect upon the operation of the receiving system. If,

instead of grounding the receiving system as above set forth, it were grounded directly, as by connecting the point 9 directly to earth, a large difference of potential would exist across the responder when the sending system was'in operation and switches of large separation would be required in the conductors a c and a. c in order to protect the res onder.

he receiving-circuit d C R (Z L, including the condenser O, responder R and any desired portion of the inductance L','is attuned to the period of the aforesaid receivingloop antenna by the adjustable inductance L or by the adjustable condenser C, or by both; and the adjustable contacts 0, 0, de termine the amounts of the inductances L",

L, res ectively, which are to be included in The responder R may comprise a vessel containing an electrolyte and a glass-inclosed anode H, which is carried by an iron lunger F sur rounded by the solenoid D. '1 B is a battery and P is a potentiometer. When the key K is depressed, and before it closes the circuit of the generator G at the contact J, the sprin I, carried by and insulated from the kc solenoid D and attery B at the point h, thereby ener izin said solenoid and causing the plunger to ift the anode H out of the electrolyte. When the key K closes the circuit of the generator G, the energy of the latter is translated b the transformer M to the condenser C, whic by dischar ing across the gap S, develops electrical osci lations in the oscillationproducing circuit C S L. The energy of said oscillations is translted is atelephone, v

, closes the circuit of the the anchor spark-gap s, s' is large enough to maintain the antenna can loop while receiving; but the high tension at which the oscillations are delivered to the antenna by theablyof twoplates m, m having a large number of fine teeth, adjacent to a center plate 11,

to which the antenna lead to the inductance L is connected, 7

Fig, 2, I have shown a form ofadjustable anchor spark-gap which in practice I have found t be convenient and efficient.

In Fig. 2,.the members 1a,, and m, consist of two saw-hlades set at an angle and adjacent toa center plate n,rthe sides of which preferably are arallel to the saw-blades. By means ofthe screws 2, 2, and the slots 1, 1,

the position of the plate a, may be adjusted so as'to vary the length of the gap 8, s. It is obvious, however, that the center plate might be made stationary and! the members m, m, made movable with respect thereto.

It will be obvious that when t e gap s, s'is bridged by the conducting-arc created by the oscillations, there is but negligible poten-v tial difference between the points b ands, and betweenthe points I) and a, so that the oscillations practically short-circuit the receivingcircuit and consequently a very small difierence of ot'ential can exist between the oints d and when the key K is closed. 1; follows, therefore, that a very slight lifting of the glass-covered anodefrom the electrolyte will sufiice to protect the responder during transmission. When the transmitting-key is in normal position and the solenoid D is not energized, any signals which may be sent out home distant station may be read by the operator at the-station under discussion, who heeps the telephone T in position while sendt will be obvious that many different types of receiver may be employed; in lieu of the particular type shown in the drawings and} that many modifications may be made a both in the transmitting and. receiving systems, as well as in-the antenna and other apgaratus herein described, without departing cm the ofmy invention.

I clhim- 1:, In a wireless-telegraph system, a transmitting system, a key or energizing the same, a receiving system, a responder associated therewith, and magnetic means, enerciatcd therewith, a plunger carrying one element of said responder, a solenoid coiiperat- I ing with said Hunger and means associated with said key or-energizing said solenoid.

3. In a wireless-telegraph system, a receiving-loop antenna, a closed receiving-circuit associated therewith, and an oscillation-producing circuit so associated with said antenna that the oscillations created thereby in said antenna practically short-circuit the said roceiving-clrcnit and cause the two sides of the loop-antenna to operate in parallel.

4. In a wireless-telegraph systcnna receivassoci'atcd therewith, an oscillation-producing circuit and means so connecting the latter with the antenna that the oscillations created thereby in said antenna produce a practically vneg ible diil'erence of potential between the lation-producingcircuit including a helix, an.

antenna, means connecting said antenna to ground through said helix, a receiving-cm cuit, and means connecting said receivin circuit to ground through said helix.

. 8. In a wireless-telegraph system, ananchor spark-gap, an antenna connectedto one member of saidspark-gap, an oscillation-producing circuit connects to the othermember of said spark-gap and a receiving circuit connected to both members thereof.

9. In a wireless-telegraph system, an anchor sparkgap, an antenna connected-to one member of said spark-gap, anoscillationproducing circuit, including a helix, connected to the other member of said spark-gap, a receiving-circuit connected to both members thereof, and a ground connection through said helix forsaid receiving-circuit.

10. In a wireless-telegraph system, an. anchor spark-ga comprising a member provided with a p urality of teeth, acooperating lug-loop antenna, a closed receiving-circuit 6o gized by said'key, for moving one element of said responder away from the other element thereof;

'2. In a wireless-telegraph system, a transmitting system, a key or energizing the 65 same, --a; receiving system, a responder assomember adjacent thereto,'. means wherebw the length of the. spark-gap may be varied; an antenna connected to one member-ofr'said spark-ga an oscillation-producing circuit connecte to the other member ofsaldsparltgap, and a receiving-circuit connected toboth members thereof.

' 11. In a Wireless-telegraph system, an anchor spark-gap consisting of two members, one member consisting of a plurality of parts each provided with a lurality of teeth, a cooperating member a jacent to said arts, means'whereby the length of the spar -gap may be varied, an antenna connected to one member of said spark-gap, an oscillationproducing circuit connected. to the other member of said sparkap, and a receivingcircuit connected to bot members thereof.

12. In a wireless-telegraph system, an anchor spark-ga comprising a member provided with a p urality of teeth and a cooperating member adjacent thereto, an antenna connected to one member of said spark-gap, an oscillation-producing circuit connected to the other member of said spark-gap, and a receiving-circuit connected to both members thereof.

13. Inawireless-telegraph system,atransmitting system, a key for energizing the same, a receiving system, a responder associated therewith, and electrically-operated means controlled by said key for moving one element of said res onder away from the other element thereoi 14. In a wireless-telegra h system, a responder comprising two re atively movable elements, a transmitting-key, and elect ricallyoperated means controlled by said key for producing relative movement between the elements of said responder.

In testimony whereof I have hereunto subscribed my name this 29th day of December, 1905.




Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2432100 *Jan 22, 1945Dec 9, 1947Bell Telephone LaboratoriesTwo-way signal transmission system
US2471436 *Jan 4, 1943May 31, 1949Standard Telephones Cables LtdTransmitter-receiver system
Cooperative ClassificationH03B11/02