US2408034A

US2408034A - Direction finder antenna

Info

Publication number: US2408034A
Application number: US593604A
Authority: US
Inventors: Bellare David
Original assignee: Standard Telephone and Cables PLC
Current assignee: STC PLC; Federal Telephone and Radio Corp
Priority date: 1945-05-14
Filing date: 1945-05-14
Publication date: 1946-09-24
Anticipated expiration: 1963-09-24

Description

Sept. 24, 1946. D. BELLARE DIRECTION FINDER ANTENNA Filed May 14, 1945 5 Sheets-Sheet 1 INVENTOR. aqwo 'Bt L/IEE BY //4;;

A TTDRIVE Y Sept. 24, 1946. D. BELLARE 2,408,034

DmEcTIoN FINnER ANTENNA Filed May 14,, 1945 5 Sheets-Sheet 2 IN VEN TOR. DIYV/O 85M fl/FE ATmFNEY Sept. 24, 1946.

DIRECTION FINDER ANTENNA Filed may 14, 1945 5 sheets-sheet 5 A TTOIPNEY D. BELLARE 2,408,034?

Sept. 24,1946. b, BELLARE 2,408,034

DIRECTION FIKDER ANTENNA Filed May 14, 1945 s-sheets-sheet 4 IN VEN TOR..

VBY iTQP/VE) Sept. 24, 1946, D; BE LARE 2,408,034

DIRECTION FINDER ANTENNA Filed May 14, 1945 5 Sheets-Sheet 5 IN V EN TOR. DAV/0 BZZ/l/FE ATTORNEY Patented Sept. 24, 1946 UNITED STATES ATENT OFFICE DIRECTION FINDER ANTENNA David Bellare, Brooklyn, N. Y., assignor to Fedoral Telephone and Radio Corporation, New York, N. Y., acorporation of Delaware Application May 14, 1945, Serial No. 593,604

"This invention relates to improvements in direction finder antennae and more particularly to a crossed loop wave collector used with :a sensing antenna in direction finding detection.

My invention provides certain improvements in the construction, arrangement of parts and effectiveness .of loop antennae used in direction finding systems.

An objection of this invention is to provide a novel improved antenna assembly including crossed loops, sense antenna and counterpoise, which is especially adapted for use in connection with direction finding systems either of a portable or fixed character.

Another object of this invention is to provide an antenna assembly of compact and rugged character particularly adapted for use on vehicles.

A further object of this invention is directed to "providing an antenna assembly including crossed loops, sense antenna, and counterpoise in which the sense antenna and counterpoise are interconnected by a shielded dummy loop network immediately adjacent thereto.

Another object of my invention is the utilization of the supporting cross arms of the loop antenna as counterpoise members for a vertical antenna.

A still further object of my invention is the provision of additional counterpoise members, orientation of which can be altered for initial adjustments. These additional counterpeise elements may be adjusted in vertical {angle to compensate for possible directional errors.

With the foregoing and other objects in view, advantages of my invention will become apparent from the following description; illustrated in the accompanying drawings wherein:

Fig. 1 is a vertical view in elevation of an antenna assembly according to my invention;

Fig. 2 is a top plan view of the general antenna assembly illustrated in Fig. 1 i

Fig. 3 is an enlarged cross-sectional view of the upper portion of the loop antenna assembly in accordance with my invention;

Fig. 4 is an enlarged vertical view of the upper portion of the loop antenna assembly, with the Weatherproofing cover removed;

Fig. 5 is an enlarged cross-sectional'view of the junction point'of counterpoise and vertical sense antenna at a point 'midwav of the supporting masty Y Fig. 6 is a View in plan of afurther embodiment loflthe invention; and

Fig.7 is a fragmentary view of a detail of Fig; 6.

8 Claims. (01. 250-33) Referring to Figs. 1 and 2, the antenna assembly includes a vertical supporting memberor rod 1 from the vertical midpoint of which extend four radial arms 2 spaced 90 relatively to one another, and attached to therod I by an insulating connector 3, providing rigid support for the arms 2. The bottom of the supporting rod I is held in a strengthening support l which, in turn, is mountedfupon a generally cylindrical base member 5; The latter, in turn, may be attached to any suitable supporting rod or antenna mounting shaft or mast. The 'four arms Z'may be interconnected by bracing bars attached thereto by suitable insulated clamping device l.

The crossed loop may be formed by two flexible shielded cables 6 and 9, the apices of which pass through a, top mount Ill attached to supporting rod I, the ends of which are fastened within the base'member '5 and the central portions of which are held by fastening devices H on the endsof the respective arms 2. Above the top mount it may be fixed an insulating and weatherproofing cap. l2 which supports insulator means it surrounding the vertical sense antenna l4.

In Fig. "'3 I have shown details of the protectiing and insulating cap l2 of the present invention. This combination of top mount Ill and insulating cap 12 serves to provide support at the apices of shielded

cables

8 and 9, as well as means of support and insulation of vertical sense antenna M. The mount it consists of a tube of proper length, fiared outwardly at a 45 angle at the top. The sloping sides l5 are formed with four special openings It to receive the shielded cables and-insulating bushings, more fully described in copending applications of Trevor H.

Clark, S. N. 478,081, filed March 5, 1943.

The vertical sense antenna 14 passes upward close by the apices of the loops of shielded

cable

8 and 9. In order to prevent shorting, the insulation means l3 includes an insulating bushing li mounted at thecenter of circular plate l8 on weatherproofing cap l2, with the vertical sense antenna It passing upwardly therethrough. Further protection and support is provided at this point by ceramic insulator l9.

In Fig. 4 a planview of the loop antenna shows provision for the displacement of cables 81 and 9 in juxtaposition with the verticalantenna I4. As an alternative it would be possible to construct the loops in the usual manner, while mounting the verticalantenna oil-center of its base, in order to provide clearance at the .apices of the crossed loops. In Fig. f1 the vertical antenna I 4 crowds the two crossed

loops

8 and 9 to one side, but such a change in position of these portions of

cables

8 and 9 does not effectually alter the constants or characteristics of the loop antenna.

The .central portion of the loop structure, showing details of construction and electrical connections, is illustrated in Fig. 5. The radial arms 2 are supported in

insulating bushings

20 and 2! composed of a circular insulator '22, a

flanged collar 23, and a ring nut 24. The arm Z has a threaded portion 25 to engage in internal threads 25 of collar 23. The arms 2 may be employed not only as a means of support for the loop structure but also as a counterpoise for the sense antenna [4. Y

At the internal end of each arm 2 there is a terminal screw 21 tapped into the end of the arm, holding a lug 28 connected in turn by lead 2 9 to bolt 30 through lug 3!. Bolts 30 serve to hold in position an insulating block 32 supported on flange la of supporting tube I. Supported on insulating block 32 is the vertical antenna l4 with a thickened base 33. A bolt 34 formed integrally with base 33 is passed through insulating block 32 and secured by hex nut 35 which also secures lug 36. A lead 3'! from lug 36 passes through'an insulator 38 mounted on shielding can 39. The leadins 40 to a dummy loop from each of the bolts 30 are brought from lugs'4l held by nut 42 through insulators 43 into the shielding can 39. The dummy loop 44, more particularl described in the aforementioned application of Trevor H. Clark, showing proper portioning'of circuits, assumes balancing'of circuits so that the resonant frequency as determined by the capacity of the vertical antenna to the radial arm counterpoise, the shielded loop and mast, the capacity of the counterpoise to the shieldedloop and mast, the internal capacities of the windings 'of the dumm loop network, and internal shield, will be greater than the operating frequency of the loop.

The entire shielding can 39 may be suitably mounted by some means such as shown by the flange 45 supporting an insulating base 46 held in place by bolt 41 and nut 48. Leads 49 from thejdummy loop network 44 pass through the insulating base 46, ending in terminals 50.

For the purposeof properly proportioning the verticalsense antenna I4 to the counterpoise arms 2 in their resonant circuit, such vertical antenna may be so constructed as to be adjustable in length.

In order to provide means for adjustment of any additional radial arms used as counterpoise members, a system illustrated in Figs. 6 and 7 is shown, including a plurality of radial arms, some of which are adjustable in the vertical plane. Alternate arms, for example, are each shown to include a stub for connection with extension 52 by means of

tongues

53, 54, and a bolt 55.

This construction allows for orientation in the vertical angle of 180, which may be utilized to compensate for possible directional errors. If desired, connecting bars like the bracing bars 6 in Fig. 2 may be included, but if included the adjustable arms 5!, 52 must be short enough to clear the bars 6, or be limited in their adjustment.

.From the foregoing itwill be clear that the utilization of the four radial supporting arms 2 as a counterpoise array for the vertical sense antenna l4 contributes to a more compact and rugged construction than wouldbeobtainedwith described in some detail. structural details given have been shown by way 4. a counterpoise array supported above the loops. The rigid construction is particularly suitable for use on vehicles, and for use in areas of limited clearance.

The feature incorporated in my invention wherein the sense antenna and counterpoise are interconnected by a shielded dummy loop network immediately adjacent thereto provides an assembly of maximum efiiciency, due tonegligible losses in transmission leadins.

-As will also be clear, the use of additional counterpoise members so constructed as to be variable in orientation is a novel feature of my invention. Simple adjustment of these additiona1 arms provides a means of compensation'for possible directional errors.

For the sake of clarity, my invention has been of examples, and not as a limitation on the scope of my invention as set forth in the objects and accompanying claims.

I claim:

1. A wave collector comprising a vertical supporting member a pair of antennaloops 'positioned substantially at right angles to each other and having the common axis thereof in common with the vertical axis of said member, a plurality of arms extending radially of said member at a location within the area of said loops, a vertical sensing antenna extending upwardly from said member from a point adjacent said arms'and means for coupling said. arms as a counterpoise 3. A wave collector according to claim 1 wherej in at least certain of said arms includ means for orientation of such arms in vertical planes common to the vertical axis of said supporting member.

4. A wave collector comprising a vertical supporting member, a pair of antenna loops positioned substantially at right angles to each other and having the common axis thereof in common with the vertical axis of said member, a plurality of arms extending radially of said member to support the outer portions of said loops, means to insulate said arms from said member and said loops. a vertical sensing antenna extending upwardly from said member from a point adjacent said arms, and means for coupling said armsas a counterpoise to said sensing antenna. 7

5. A wave collector comprising a vertical supporting member, a pair of antenna loops positioned substantially at right angles to each other and having the common axis thereof in common with the vertical axis of said member, a plurality of arms extending radially of said member at a location within the area of said loops, avertical However, various of said arms, and means for coupling said arms as a counterpoise to said sensing antenna.

7. A wave collector comprising a vertical supporting member, a pair of antenna loops positioned substantially at right angles to each other and having the common axis thereof in common with the vertical axis of said member, a plurality of arms extending radially of said member and diametrically of said loops, means to support the outer portions of said loops from at least certain of said arms, said arms being insulated from said members and said loops, a vertical sensing antenna extending upwardly from the junction of said arms, and means for coupling said arms as a counterpoise to said sensing antenna.

8. A wave collector comprising a, vertical supporting member, a pair of antenna loops positioned substantially at right angles to each other and having the common axis thereof in common with the vertical axis of said member, a plurality of arms extending radially of said member at a location within the area of said loops, means connecting certain of said arms in insulated. relation with respect to the outer portions of said loops to support said loops, others of said arms being provided with means for adjusting a part thereof laterally with respect to a plane common to said certain arms, a vertical sensing antenna extending upwardly from said member from a point adjacent the junction of said arms, and means for coupling said arms as a counterpoise to said sensing antenna.

DAVID BELLARE.