US962262A - Wave-detector for wireless telegraphy. - Google Patents

Description

W. SUHLOEMILCH & P. P. PICHON.

WAVE DETECTOR FOR WIRELESS TELEGRAPHY. APPLIGATIONTILED APR 14. 1906.

962,262. Patented June 21,1910.

I Mandi UNITED STATES PATENT OFFICE.

WILHELM SCHLOEMILCH, or BERLIN, A D PAUL FERNAND} PIGHON, or sfinnNnn',

NEARBERLIN, GERMANY, ASSIGNORS 'ro GESELLSCHAFT run DRAHTLOSE TELE- GRAPHIE m. :B. 11., 0F BERLIN, GERMANY. H

WAVE-DETECTOR FOR WIRELESS TELEGRAPHY.

Application filed April 14, 1906. Serial No. 311,678. I I

To all whom it may concern:

Be it known that we, WILHELM SCHLOE- MILcH, a sub ect of the King of Prussia, re-

. drawing, forming a part of this specification.

This invention relates to detectors such as are employed in wireless telegraphy for indicating the presence of electric waves, and more particularly to those detectors which are formed of one or more contacts sensitive to wave action. To this classbelongs the ordinary coherer and also the microphonic contact which is'generally; formed. of two conductors of the first class which contact each other with slight pressure. This contact pressure is. very small; in the detectors hitherto employed of this kind, so that even very small vibrations-yvhich are unavoidable during w0rking, suflice to alter the contact, which of course gives rise to disagreeable interruptions in workin If in the contacts hithertoknown a hi er pres sure be employed which renders. tiem 1ndependent .ofexternal 'vibrations, they lose the property of. being sensitive to waves. Now this invention relates to a wave-sensitivecontact which, owing to'the use ofcertain materialsfor the contact. elements, permitsthe use of a high contact pressure without losing its sensitivene'ss to waves. On the contrary it hasbeen found that the wave sensitiveness where such materials areiusedcomes out particularly favorable only at higher pressures at which the known contacts entirely lose their effect. The materialswhich. exhibit the said. properties are the, naturally exist ing manganese compounds, asm'ay be ascertamed by experimentafor instance, ps'ilomelane (barytiferous oxid of manganese), pyrolusite (peroxid of manganese), braunite (sesquioxid of manganese),manganite (hydrous-oxid of manganese) and others, in contradistinction to chemicall' ure com. pounds, such as manganese an t e binoxid of manganese previously roposedfor this purpose. The reason wfy the naturally found compounds have the desired property andnot the chemically pure com ounds is supposed to be that the natura y i found compounds have moisture either chemically or mechanically combined with them. These materials may be employed for either both contacts or only one. It is, however, preferable to form one of the contact bodies of a good conducting material, preferably of a material which does ,not oxidize or only oxidizes with difliculty, for instance, plati: num, gold, silver, aluminiumand even lead arefound to be very advantageous. In the accompanying drawings: Figure 1 shows a form ofconstruction ofthe wave sensitive contact piece. Fig. 2 shows a rejceiver connectionsin which the detector works with an auxiliary source of potential, and Fig. 3 a receiver connection'ln. which theldetector works without auxiliary potentia I I -,In Fig. 1, 1 indicates a piece of psilom'e- Ian which is preferably embedded in tin 2 which is surrounded with abrass 'sheath or socket 3. Against the upper surface of the psilomelan a platinum pin,5 soldered to a screw l strongly presses. ranged in a vulcanite plug 6 which inturn is displat-eably held by-meansiof screw thread in the brass sheath or socket 3. On the upper end of theviilcaniteyplug 61a metal plate 7' is attached by means of screws ter, the comparatively high'pressur'e of the electrodes one upon, the other, may. be easily kept constant. ,The form, and size of the contact'surfaees of both bodies-according to the choice of the same have also been.

found to be of im ortance for '-obtaining favorable action, I for instance,.psilom elaneand platinum beemployed it is preferable cause the platinum to act' in the form The screw is -arand a'short conductor8 establishes an elecof a pencil on a polished surface of the psilomelane. If, in place of the platinum,

lead be employed this is preferably used in the form of a large plate which is pressed with great pressure against the psilomelane.

The connection of this improved detector with the circuits for wireless telegraphy may be made in the same way as the connection of the ordinary detectors at present employed for similar objects such, for instance, as coherers, electrolytic cells or microphone contacts. A method of connecting up the mproved detector is shown as an example in-Fig. 2. The receiver circuit is here composed of an aerial wire 9, rimary transformer coil 10, variable sel -induction coil 11, an adjustable condenser 12, and a connecting Wire 13 carried to earth or to an equivalent. The detector circuit is inductively coupled with the receiver circuit, and also, contains in addition to the secondary coil 14, the adjustable condenser 15, and wave sensitive contact 1, 5, in connection wlth which an adjustable condenser 16 is inserted in parallel. The wave sensitive contact is connected over choking coils 17 with the potentiometer 18, which serves for producing the necessary potential at the electrodes of the wave sensitive contact. An equalization of the potentiometer 0 tential over the coil 14 is prevented by thecondenser 15. 19 indicates an energy indicator (telephone, galvanometer or the like) for enabling the alterations ..,which take place in the detector undertlie influence of the electric waves to be ascertained. The coupling of the receiver circuit with the detector circuit may of course instead of being-inductive also be made conductive.

The auxiliary potential to be impressed upon the wave sensitive contact 1, 5, varies according to the kind of material employed and is also dependent on the shape and kind of contact surface. Thus it is not possible to fix a given referable value for the auxiliary potentia to be employed. This for psilomelan is about 1 volt, if it be desired to obtain a maximum sensitiveness with the.

smallest amount'of sound in the telephone. If it be intendedto increase'the maximum strength of the sound,'it is necessa to increase the auxiliary potential, whereby how In using tained by having a permanent current of about one to two milliamperes flowing through the wave sensitive contact 'part. The

The physical properties of the bodies found to be effective to bring about the improved actionhave not hitherto been ascertained. As regards this, it may be pointed out that all hitherto discovered naturally found manganese compounds contain to a high extent moisture or water chemically or mechanically combined. It has not been pos sible up to the present to discover whether the improved action is perhaps to be ascribed to these properties of the bodies alone, or not. Having explained our invention, what we do claim and desire to secure by Letters Patent is:

1. A wave detector for wireless telegraphy, consisting of two contact bodies, one I of which is formed of one of the naturally .found manganese compounds containing moisture.

2. A wave detector for Wireless telegraphy, consisting of two contact bodies, one of which ,is formed of one ofthe naturally found manganese compounds containing moisture, and the other of a material which oxidizes with difficulty.

3. A wave detector for wireless telegraphy, consisting of two contact bodies, one of which is formed of one of the naturally found manganese compounds containing moisture, and thepther of a material which oxidizes with diificulty, said contacts touch- M ing each other with apredetermined pressure. I

4. A wave detector for wireless telegraphy consisting of two contacting bodies, one of which is .formed of psilomelane.

In witness whereof, we hereunto subscribe our names this 31st day of March A. D. 1906.

' WILHELM SCHLOEMILCH.

PAUL FERNAND PICHON. Witnesses:

Wonnnu.m Ham, Hnxizr Harlin.

Images