US1945735A

US1945735A - Antenna compensator

Info

Publication number: US1945735A
Application number: US470461A
Authority: US
Inventors: Chester L Davis
Original assignee: Wired Radio Inc
Current assignee: Wired Radio Inc
Priority date: 1930-07-24
Filing date: 1930-07-24
Publication date: 1934-02-06
Anticipated expiration: 1951-02-06

Description

Feb. 6, 1934. c. L. DAVIS ANTENNA COMPENSATOR Filed July 24, 1930 2 Sheets-Sheet l INVENTOR.

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ANTENNA COMPENSATOR Filed July 24. 1950 2 Sheets-Sheet 2 I I E;-

g (2/ I 95 Z v INL'EN TOR Patented Feb. 6, 1934 PATEFQT @FTFEQE ANTENNA CGMEENSATOB;

Chester L. Davis, Kecinili, Iowa, assigned to Wired Radio, Inc, New York, N. Y., a corporation of Delaware Application July 24, 1930. Serial No. 479,461

7 Claims.

My invention relates broadly to radio signaling systems and more particularly to the construction of a device adapted for connection in circuit with an antenna conductor for compenfor the effects of temperature changes upon such conductor.

One of the objects of my inventi n is to provide a construction of antenna compensator for maintaining constan frequency operation of an 5 antenna conductor independent of changes in temperature conditions.

Another object of my invention is to provide a construction of compensator for connection in circuit with an antenna conductor for effectively compensating changes in length of the antenna conductor under conditions of variations in temperature.

A further object of my invention is to pro vide a construction of antenna compensator for correction for variations in frequency characteristics of an antenna system for variations in temperature conditions by arranging thermal expansion means directly adjacent the antenna conductor and subjecting the antenna conductor to changes in frequency characteristics equal and o; Jcsite to normal changes due to variations in teinperature.

G-ther and further objects of my invention will be understood. from the specifi ation hereinafter following by reference to the accompanying draw ings in which:

Figure 1 is a peepective View of antenna compensator and associated rigging used in signaling systems; Fig. 2 is a longitudinal section taken through one form of antenna compensator employing the principles of invention; Fig. 3 is a transverse vertical section taken on line 3-3 on Fig. 2; Fig. 4 is a theoretical view illustrating the principles involved in the antenna compensator of my invention, the impedance element being shown in elevation; Fig. 5 is a sectional view of a modified form of antenna coinpensator embodying the principles of my invention with parts shown in elevation; Fig. 6 is a longitudinal cross-sectional View through the antenna compensator with parts illustrated in section 1; Fig. '7 is a cross-sectional View taken through the thermostatic control device in the compensator system of Figs. 5 and 6 on line 7-7 56 of Fig. 6; 8 is a cross-sectional View taken on line 8-8 of Fig. 6; Fig. 9 is a cross-scctional view on line 9-9 of 6; and Fig. 10 is a theoretical view illustrating the principle of opera tion of the antenna compensator illustrated in Figs. 5-9.

Referring to the drawings, reference character 1 designates the antenna conductor which is secured to the eyelet member 6 in one end of the cylindrical member in the form illus trated in Fig. 2 this casing may be made of insulation material. In the modification illustrated in Figs. 5-9 the casing may he made of conductive material. lhe rigging for the device of my invention as shown in Fig. 1 is such that the compensator is insulatingly supported by means of insulator 3 respect to halyard a and supporting mast 5. The cylindrical casing 2 is closed at one end by member '7 which may be screw threaded to engage interior screw threads on the inside walls of casing 2 with pins 0 8 projecting radially into end of plate '7. The ring member 9 extends through the end plate '7 for securing insulator 3 hereto. An insulated support 10 is spacially mounted by suitable means designated at 11 in a position spaced from the interior walls of the casing 2. The member 10 is wound by the turns 12 of an inductance which is connected at one end with the end of the antenna conductor 1 as indicated at 13. The end 13 of the inductance i2 is also 8 connected to the end of the thermometer The inductance 12 is tapped along the length thereof to connections which extend into the bore of the thermometer at is, 15, 17, 18, 19, 2o, 21 and 22. The thermometer is suitably secured to the interior wall 2 and assumes the temperature of the surrounding atmosphere. In order that the thermometer 25 will at all times be retained in its lowest position, I provide a weighted fin 2 on the casing 2 which maintains the casing 2 in a predetermined. position. As changes occur in the length of the antenna 1 due to changes in temperature corresponding changes occur in the thermometer 25 and as the mercury therein expands the several taps along the inductance 12 are electrically shunted thus serving to reduce the effective period in proportion to the increase in period of t; e antenna conductor 1. Frequency variations the antenna conductor 1 are accordingly compensated by frequency variations in inductance 12. That is, for changes in frequency characteristics in antenna 1 there are equal and opposite changes frequency characteristics in the inductance 12 according to temperature changes. Variations 10s in signaling frequency are thereby avoided by maintaining an antenna of constant frequency characteristics independent of temperature changes.

In Figs. 5-9 I have shown a conductive tubu- 11o lar member 26 surrounding the inductance 12. Adjacent one end of the tubular member I arrange a spiral bi-metallic strip 27 having por-- tions 27:: and 27b of materials having different coemcients of expansion. The center of the bimetallic strip 27 is connected to the connecting ring 6 and the end 12b of the inductance 12. A strip of insulation 28 is provided on the exterior surface of a number of the convolutions of the bi-metallic strip 27 preventing electrical shortcircuit with the interior walls of the tubular cas ing 26. A guide member 31 in the form of a disc centers the bi-metallic strip in position and allows the expansion and contraction thereof. As the temperature increases the bi-metallic strip expands and moves closer to the interior wall of tubular member 27. The end of the inductance 12 is connected to the bi-metallic strip 27 as represented at 12a. The expansible strip serves as illustrated in Figs. 7 and 8, to vary the capacity across the ends of the fixed inductance 12. That is as the temperature rises the bi-metallic strip expands and the capacity increases due to the decrease in spacial relation between the bimetallic strip 27 and the inner walls of the tu bular member 26. The inductance 12 is tl1erefore tuned to a frequency characteristic compensating for changes in frequency in conductor 1 under conditions of temperature change. As the temperature decreases the bi-metallic strip 27 contracts thereby increasing the effective pacity across the inductance l2 and compensating for the reduction in length of the antenna conductor 1.

While I have described my invention in certain preferred embodiments I desire that it be understood that modifications may be made and that no limitations upon my inventions are intended other than are imposed by the scope oi. the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. An antenna compensator comprising a suspension member connected with an antenna conductor said suspension member including an inductance device electrically connected in series with the antenna conductor and forming an electrical extension thereof and thermoslatic means connected with said inductance device for varying the frequency characteristic thereof for compensating for changes in frequency of said antenna conductor under conditions of variable temperature.

2. An antenna compensator comprising a suspension member connected with an antenna conductor said suspension member including an inductance device electrically connected in circuit with the antenna conductor, and forming an electrical extension thereof and thermally responsive means connected with said inductance device for changing the frequency characteristics thereof in an opposite sense to the normal change in frequency characteristics of said antenna conductor under conditions of variable temperature.

3. An antenna compensator comprising a suspension member connected with an antenna conductor said suspension member including an inductance device electrically connected in series with the antenna wire and forming an electrical extension thereof, a thermally responsive device carried by said suspension member and electrically connected with said inductance device, said thermally responsive device being disposed adjacent said inductance device for changing the capacity across the ends thereof and modifying the frequency characteristics of said antenna conductor for compensating for the eifects of temperature changes upon said antenna conductor.

4. An antenna compensator comprising a casing member, means at one end of said casing member for suspending said casing member, means at the other end of said casing member for suppo ting an antenna conductor, a weight attached to said casing member for predetermining the position thereof when in suspension, an inductance device mounted within said casing member and electrically connected with said antenna conductor, and a thermostat disposed within said casing member immediately above the weighted portion thereof and electrically connected with said inductance device for predetermining the effective value of inductance in circuit with said antenna conductor.

5. An antenna compensator comprising :1. cas ing member, means at one end of said casing member for suspending said casing member, means at the other end of said casing member for supporting an antenna conductor, a weight attached to said casing inen'iber for predetermining; the position :hereof when in suspension, an inductance device mounted within said casing member and electric-aily cc mooted with said antenna conductor, and a thcrinostatically controlled variable condenser disposed within said casing member and electrically connected in shunt with said inductance for pre termining the frequency character of said inductance in series with antenna conductor in accordance with conditions of temperature.

An antenna compensator comprising a conductive tubular casing, suspension means connected to one end oi said casing, an antenna conductor connecled to the opposite end of said casing, a partition member laterally dividing said easing into separate sections, an inductance insu ingly spaced from the interior rails of said casing member and ii one end electrically connected with said antenna conductor and the other end connected. with said tubular casing in one of the sections th eof, a thermostatically controlled capacity elc nt mounted in the other of the sections 0'" casing member, said capacity element being variable in the spacial relation thereof with respect to the interior walls of said tubular casing for controlling the frequency characteristics of said inductance in series with said antenna conductor in accordance with temperature conditions.

7. An antenna compensator comprising a suspension member, supporting m. ins connected to one end of said suspension rm. nher an antenna conductor connected with other end of said suspension member, an insulated support extending axially through said casing lllfil'fill'el', an in sula'ed spider disposed between each end of said insulated support and the interior walls of said casing member, an inductance wound on said insulated support and connected one end thereof with said antenna conductor, mercury their-iostat disposed beneath said inductance and within said casing member, contacts '1 ranged at spaced intervals along mercury thermostat and ccnnected with taps on said inductance, and means for gravitationally maintaining said thermostat beneath said inductance while said Cc sing member is suspended.

CHESTER L. DAVIS.