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Radio Engineers, Proceedings of the Institute of

Issue 6 • Date Dec. 1919

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Displaying Results 1 - 11 of 11
  • [Front cover]

    Page(s): c1
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    Freely Available from IEEE
  • Information about the Society

    Page(s): 555 - 556
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    Freely Available from IEEE
  • Contents

    Page(s): 557
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  • Officers and Board of Direction, 1919

    Page(s): 558
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    Freely Available from IEEE
  • Long Wave Reception and the Elimination of Strays on Ground Wires (Subterranean and Submarine)

    Page(s): 559 - 583
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    The question of optimum length of (buried) ground wires for reception at a given wave length is discussed, and experimental data are given. The signal strength obtainable on such wires under various conditions is considered. The signal-to-stray ratio on ground wires as compared to that on loop receivers (rectangles) is found to be more advantageous, particularly under carefully chosen conditions. After considering a number of methods of reducing strays which have already penetrated into the receiver circuits, there are described a number of more effective methods for reducing strays before their entrance into the receiver. Thus strays can be balanced out by using a sea wire and a land wire as opposing collectors, with an adjustable-phase differential coupling of some sort. The wiring of the arrangements used and the practical adjustment are given, together with some of the experimental results obtained therewith. The distance of origin of strays (or interfering signals) can be adjusted for in balancing these out, so that an interesting "focussing effect" is obtainable wherein the effect of a stray (or signal) in the receiver depends on the distance to its source. The ratio of improvement in readability of signals thru strays obtained by the above arrangement is given conservatively as 8.6-to-1. Certain remarkable variations in directional effect sometimes obtained are then discussed. View full abstract»

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  • An Oscillation Source for Radio Receiver Investigations

    Page(s): 584 - 602
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    A source of long-wave, sustained oscillations, for use in connection with investigations on radio receivers, and providing standard controllable signals of the same character as those due to actual radio signals, is considered. Heretofore, such sources have had the disadvantages that they necessitated the measurement of small "received currents," and also, that considerable interference was caused by stay electric and magnetic fields emanating from the elements composing the oscillation circuit. The latter makes it difficult to carry on numerous researches in the same room on the same range of wave length; while the former cannot be accomplished with present-day apparatus for the minute currents occurring in trans-oceanic reception. The source described provides an emf. of known magnitude, rather than a current, which is exactly what occurs under operating conditions. In order to devise methods of reducing the intensity of stray fields from the source, a number of preliminary experiments are made and suitable methods of shielding and construction of oscillator elements are determined. A practical source utilizing these principles is described and construction and calibration data given. Finally, the use of this type of source in connection with transmission measurements on long distance radio communication is proposed, to replace the ordinary audibility measurements. View full abstract»

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  • On the Detecting Efficiency of the Thermionic Detector

    Page(s): 603 - 632
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    There is described a method of determining the detecting efficiency of vacuum tubes by feeding them with radio frequency current modulated at audio frequency. The theory of the method is given. In connection with such measurement, the use of a receiver shunt calibrated in terms of miles of "standard number 19 gauge cable" is advocated. For producing the radio frequency current for such measurement, a tube oscillator was employed. The audio frequency modulation was obtained either by a second tube or by a microphone howler. The apparatus is described in detail, and illustrated. Experimental data are given. A method for comparing the detecting efficiencies of a standard tube and of a tube under test is also described, and the apparatus is shown. In an Appendix, a simple method of measuring tube amplification is described. View full abstract»

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  • Discussion

    Page(s): 633 - 635
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  • Harmonic Oscillations in Directly Excited Antennas Used in Radio Telegraphy

    Page(s): 636 - 647
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    Using a symmetrically excited artificial antenna consisting of two long coils with a spark gap between them, the author measures the frequencies, decrements, and the relative amplitudes of the fundamental current and of each of the harmonics. It is found that the theoretical rectangular wave, travelling along the antenna, is modified in form, particularly if the spark is fairly persistent. Numerical data are given. View full abstract»

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  • Re-Enforced Harmonics in High Power Arc Transmitters

    Page(s): 648 - 651
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    A Poulsen arc in the antenna will give rise to a series of non-harmonic oscillations of shorter wave length, some of which may cause troublesome interference with nearby short-wave receiving stations. The effect is explained, and a method of reducing such interference by the use of a suitably tuned absorbing circuit coupled to the transmitting antenna is given. View full abstract»

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Aims & Scope

This Periodical ceased production in 1938. The current retitled publication is Proceedings of the IEEE.

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