US2973479A

US2973479A - Branched conductor structure

Info

Publication number: US2973479A
Application number: US798777A
Authority: US
Inventors: James R Bird; Harold E Stevens
Original assignee: Bird Electronic Corp
Current assignee: Bird Electronic Corp
Priority date: 1953-02-04
Filing date: 1959-03-11
Publication date: 1961-02-28
Anticipated expiration: 1978-02-28

Description

Feb. 2s, 1961 'Fili J. R. BIRD ETAT. 2,973,479 BRANCHED CONDUCTOR STRUCTURE Original Filed Feb. 4, 1953 I7 I SIGNAL INVENTORS JAMES le. am @man E. 57am/s nmwm,

MJ ATTORNEYS United States Patent() 2,913,479 BRANCHED coNnUcroR STRUCTURE James R. Bird, Chagrin Falls, and Harold E. Stevens, Lyndhurst, Ohio, assignors to Bird Electronic Corpora-l tion, Cleveland,v'0hio, a ,corporation of -Ohov Original application Feb. 4, 1953, Ser. No. 335,118, now Patent No. 2,884,603, dated Apr. 28., 1959,. Divided and this application` Mar. 11,m19 59, Ser. No. 798,777

18 Claims. (Cl. 324-95) low frequency or direct current electrical energybecause of capacitive and inductive effects, reflections and other phenomena.A High frequency energy is satisfactorily trans-I mitted on coaxial lines. andit `is known that a coaxial transmission line can be terminated substantially reflectionlessl'yV for metering purposes by a device which incorporates coaxial inner andouter conductors, onev of which is tapered and one of which is resistive, the tapered conductor desirably taking the form of a tubular metal horn surrounding a cylindrical insulator/of ceramic or like material on whichis deposited or otherwise formed a film of carbon, or equivalent, the-latter constituting the inner conductor ofthe line termination. In such arrangement the smaller end of the outer hor-n conductor makes direct'electrical connection with resistive carbon ifilm at one end of the inner conductor, thus completing the circuit.

By reason of the geometry of such a reilectionless device, it is not feasible to useconventional branch line or pick up arrangementsl with ordinary cooling, coolant circulating, heat absorbing and heat transferring techniques and devices. The presentinvention is concerned with and has for one of its principal objects the provision of a new branchline means in combination with apparatus for ree'ctionlessly terminating a coaxial transmission line and disposing of the heat energy resulting from such termination.r More specifically the invention is concerned .with the creation of a metering apparatus comprising in combination retlectionless termination means for a coaxial linel which incorporates novel cooling and heat dissipation features and branch line pick up means having manufacturing, assembling and servicing advantages.

Another object of the invention `is to provide such a combination which comprises a coaxial line component or termination of the character mentioned in association withr a casingor housing for holding a suitable liquid dielectric coolant, the line termination being immersed in theliquid dielectric coolant contained in the casing and the branch line being projected laterally into the terminaf tion through the casing as a locating plug.

It is a further feature andy objective of the invention concerned with the combination of branch line pickup, casing and contained termination or coaxial device and wherein the latter acts as a partition or flow barrier controlling the movement of liquiddielectric coolant ICC through the casing, to provide for locating the pick up on the outside of the casing yet intermediate the ends of the terminating line section. In the preferred embodiment contemplated the coaxial termination device has a tapered outer conductor having a portion of maximum cross sectional area or diameter intermediate its ends which maximum section portion engages or has substantially sealing relation with the casing walls by which it is surrounded to divide the casing chamber and constrain the owing dielectric coolant to llow through the interior of the termination. The pick up is then secured on the exterior of the casing radially outward of the large section of the termination device and has a probe which projects through the casing and into the dielectric space of the termination.

Other objects and advantages pertain to certain novel combinations of parts and features of construction, including provision for telescopic assembly of the termination device and casing wit-h advantageous locating and guiding relationships and positive securement of the conductor structure to resist shifting and turning in use. Such and still other objectives and advantages are apparent in the following detailed description of a preferred embodiment representing the best known mode of practising the invention. The description is made vin connection with the accompanying drawings forming a part of the specification.

In the drawings:

Figure l is an elevational view, partly diagrammatic and with parts brokenaway and removed, showing a high frequency electrical meter instrument which embodies the principles of thepresent invention and incorporates a reflectionless termination and a pick up branch for a coaxial transmission line;`

Fig. vl?. is a fragmentary elevational view, partly .in section, partly diagrammatic and with parts broken away and removed, showing the casing,.line termination component and branch line of the device of Fig. 1, this view being enlarged with respect to that ligure;

Fig. 3 is a transverse sectional view, with parts removed, taken substantially along the line .indicated at 3 3 of Fig. 2; and

Fig. 4 is a sectional detail taken substantially along they lineindicated at 4 4 of Fig. 3 and enlarged with respect to that figure.

The high frequency electrical meter device illustrative of the present invention .comprises a reectionless .termination T received in an elongated casing C, the latter preferably taking the `form of a'cylindrical metal tube 1 of brass or steel, although other cross sectional shapes can be used. The top and bottom ends of the casing are closed by circular metal plates or discs 10 and 11, respectively,lthe latter being permanently secured in place as by peripheral welding 12. The `top or cover disc 10 is peripherally grooved and held in place as by a clamping ring 14 and a suitable rubber annulus or AO-ring effects a uid tight seal between the casing ange and the cover 10.

At its upper end the body tube 1 of the casing C is connected to and here supported by a heat interchanger of receptacle R, the latter being vertically elongated and comprising a cylindrical metal body tube 16 .closed at the bottom by a disc similarto the disc 11 of the'casing C, and at the top by a cover 17 in the form of a circular metal disc held in place by a series of circumferentially spaced peripheral bolts 18 that are received through aligned holes in the disc andin a flange 19 formed or weldedin place about the upper end of body vtube 16.

The bottom of the receptacle `R rests on and is secured to one end of a pedestal or base 2.0 which also serves as a support for an electrical motor 21 that in turn supports and drives a coolant circulating pump 8 mounted on the motor end bell.

The connection between the casing C and the receptacle R is at their upper ends and comprises aligned metal coupling tubes 22 welded into aligned openings in the body tubes and attached together by anged joint Z3 sealed by a suitable ring or gasket. of the casing C connection is made to the lower part Aof the receptacle R through the pump 8. The center or inlet of the pump is connected by a metal tube 24 to the bottom of the receptacle body 16, a lianged joint 25 being interposed to facilitate assembly and disassembly. The

tangential outlet of the pump, indicated at 26, is connected by aligned

tubes

27 and 28 to the lower end of the casing C, la flanged joint 29 being provided between the tubes. A liquid coolant having suitable dielectric properties fills the casing and receptacle for serial ow therethrough in a closed circuit.

In operating the device the motor 21 is energized to drive the pump 8, which forces the liquid dielectric coolant upwardly into the bottom of the casing C. The tube 28 extends into the bottom of the casing through a circular opening in the bottom closure 11, the opening being on the axis of the tubular casing to direct entering liquid coolant to flow upwardly through the center of the casing over a path through the termination T, and out the discharge tubes 22 at the top of the casing into the top of the receptacle R. In the receptacle, which constitutes a heat exchanger to cool the liquid, the ow of the liquid dielectric coolant is" generally downwardly. Liquid coolant entering .the top of the receptacle from the casing C displaces liquid from the bottom of the receptacle and forces the latter to ow out the bottom dis`` charge tube 24 of the receptacle into the intake of the pump, thus completing the liquid coolant cycle.

The cooling of the dielectric liquid occurs principally At the bottom end mination has an inner resistive conductor in the form of a carbon lm (Fig. 3), or equivalent, deposited or otherwise formed on the outer cylindrical surface of a ceramic tube 41. Surrounding the inner resistive conductor in coaxial relation thereto is an outer tapered conductor '42 which may take the form of a metal horn spun or-stamped from brass or similar thin metal. The horn is logarithmically grooved or shaped in accordance with the known principles referred to above so as to provide a characteristic impedance at any point or section which is substantially equivalent to the resistance of that portion of the resistive inner conductor 40 which lies between the point or section of reference and the small end of the termination where the inner and outer conductors are joined and electrically connected.

At its upper or large diameter and the tapered horn outer conductor 42 is formed with an integral cylindrical extension or connector section 44 received telescopically within a matched cylindrical socket opening through the bottom end of a body member 45 which is of circular section and may be in the form of a spinning or, as shown, a turning of brass or other metal. The conductive parts of the device are machined from brass stock, except as otherwise indicated or implied. The tubular circular sectioned body 45 has an external surface 46, here cylindrical, that has a freely sliding tit in the cylindrical body tube 1 of the casing or, as shown, in cylindrical reinforcdrical socket axially aligned with the downwardly directed during its downward liow in the receptacle R. A cooling medium or refrigerant such as cold water from a conven` tional pressurized water supply system, may be circulated in direct heat exchange relation to the liquid dielectric in the receptacle R, the water or refrigerant being passed through a coil or coils 33, finned if desired, dispose-d Within the receptacle and having inlet and outlet tubes 34- and 35, respectively, projected through the top closure'17.

The inlet 34 is connected as to a city water supply system by suitable conduits and valves (not shown), one valve'being an electrically operated or solenoid valve preferably of the water pilot type responsive to a thermostatic switchimmersed in the liquid dielectric coolantl in the receptacle R and carried as by a boss 37 on the receptacle top. The switch is arranged to open the water or coolant supply valve when the temperature of the liquidI dielectric coolant becomes heated to a predetermined temperature, and to close the valve when the liquid dielectric coolant is cooled to a predetermined temperature. The

4energiration of the pump drive motor 21 is governed manually to be turnedvon each time before electrical energy is fed into the device or, preferably, the pump is" operated automatically to circulate the liquid dielectric coolant Whenever energy or power is fed into the termination T and simultaneously with such feeding.

The termination T extends downwardly into the casing C through the top opening in the latter, in fact, being carried by the top 17 in suspended relation'and inserted into the casing through such vtop opening in-assembly.

socket that receives the connector 44. The bottom end of a cylindrical relatively thin walled metal connector tube 50 is received in the upper socketof the body 45 andextends upwardly therefrom through the upper portion of the casing in coaxial relation and through a central opening in the top closure 10. The connector tube 50, of brass or copper, is secured in body 45, as by soldering or brazing and additionally by a plurality of radial set screws, not shown, threaded through the body 45 and the wall of the connector tube 50, so as to bear against and become embedded in a plastic sealing ring which locates and supports the upper end of a tubular guide 118 for the flowing liquid dielectric coolant.

A ring 54 is formed on or welded -against the underside of the top closure 10 about the center opening that receives the connector tube 50. Radial set screws, not shown-'are threaded through the ring 55 and are received through openings in the connector tube so as to bear radially against and become interlockingly embedded in a suitable annular block or insulator 60, of dielectric plastic material which supports the center conductor assembly of the termination, as shown in the parent application referred to. A number of axially elongated circumferentially spaced openings or slots `61 are formed in that portion of the connector tube 50 which lies between thecircular sectioned body 45 of the termination and the annular insulating block 60 in the top opening of the casing, these apertures placing the interior chamber of the connector tube in communication with an upper annular casing chamber 62 which is above the circular body 45 and in communication with the heat exchanger receptacle R through the connecting tube 22.

v- The lower end, of the ceramic tube 41 is embraced by the small end of the outer or horn conductor 42. The upperend, of the ceramic tube -is connected to a metal center conductor connector 64 within and coaxial Ito the connector tube 50. This center, connector is of circular section and is formed with a tapered transition portion 69 having an external frusto-conical surface also concentric to the axis of the termination'. At its lower end, which is the same diameter as the ceramic tube 41, the transition portion 69 has an internal thin walled cylindrical socket that receives a reduced diameter upper end portion of the lceramic tube 41, the latter beingpre liminarily turned or `ground down -to the Ydesired diameter andzcoated with-silveror other conductive metal paint oif`plt`ed'withl copper to provide a terminal band which extends-onto andmakes annular electrical connection with the lend portion of the deposited carbon film coating. vThe'circulartermination body 45 is formed with an internal frustoconical surface 68 concentric to the longitudinal axis of the termination and in spaced confronting relation to the surface ofthe tapered transition portion y69. The

surfaces

68 and 69 constitute a tapered transition section byv which the diameters of the inner and outer conductor-components of the termination are altered'from thoseprevailing at theA large diameter end of thefhornconductor 42m those of fthe connectors 50 amd64, the latter orresponding' in diameter to the' outer and enrconiuctifrs,in respectively, of the coaxial, transmi ionfline'towhich'tthe termination device is to'be.connected`. f

High frequency electrical energy from a signal gen-` erator such asa television transmitter or other source, which'enerigy is to be absorbed and converted into heat -byg the termination T, is conducted to the termination over inner -and `outer conductors 71 and 72 of a suitable coaxialtransmission line, indicated diagrammatically in Fig. 1. The coaxial transmission line, conventional in character, is provided with terminal fittings by means of which the inner and outer conductors 71 and 72 are respectively connected to inner terminal 73 and the portion of the connector tube 50 which projects through the top Afof the casing and constitutes the connector terminal for' the `outer conductor ofthe termination T. Contact is made between :the horn conductor 42 and the resistive inner conductor 40 by a reduced diameter cylindrical end 97 which is integral with and extends as anfaxial continuation or extension of the horn and is clamped 'about the resistive coating terminal end. The 1r f ,',conduc'tor `,42: is formed adjacent its terminal end with apertures., suchl fas` axially elongated slotsl98 for admittingfliquid coolantl to the dielectric space between the termination conductors. These slots are spaced uniformlyaboufthe lcircumference.of the horn end and one of themi is continuousthrough the end of the horn to permitllexp'ansion and` contraction of the latterin yieldingly gripping the end ofthe inner conductor. The` terminationT isv aligned axially with the entrant tube through which the circulating liquid dielectric is introduced into the casing C; the inilowing liquidbeing ltlrus directed to flow ,axially against the small yendfot theYtermination.V Toguide and conne the flow of theliquid afu'nnel i106 ern-braces both the end of the tenmination and the inletend .of the entrant .tube 28. The funnel hasY a sternvportion 108 received about the ll end ofthe horn, conductor'42, the funnel stem beingnsolpdered to and making substantially annular sealing conta-ct with the external surface of the horn condiitor. at a circular: line 104 above or spaced toward the largel end of the termination from upper ends of the axial slots 9Nandanother group of horn slots 116 which admit 4the liquid dielectric coolant into annular space 96 between the horn `conductor and the inner resistive film conductor 4,0. At its lower end'the funnel 106 is formed with a bell 1111 which surrounds the end of the entrant tube28 in embracing but slightly spaced relation, the annulariclearance thus provided being indicated at 112. Thebell end .111 is formed with a ilared lip 114 which acts asa pilot to guide the funnel overY the end of the tube `23 in assembling the parts into the telescoped relation shown. f" The liquid flielectric coolant surrounding the tapered outer or, horn conductor 42 is in quiescent state,v orsub.- stantially so,rtl1e flowthrough lower outer portion 115 of(- the casing chamber being, relatively small or nonexistentangl `lresulting from permissible leakage between the bodyAvSf` of the termination and the casing walls or renommer-instit? Equalization of pressure between the interior or dielectric space ofthe termination and the outer casing chamber is obtained'thr'ough the annular clearance 112 between the funnel 106 and the tube 28.

In circulation of the liquid dielectric coolant about its circuit the flow through the casing C is confined substantially to the annular dielectric space separating the inner and outer conductors of .thetermination even though the casing is completely filled with and the termination is immersed in the liquid dielectric coolant and even though the annular dielectric space between the coaxial conductors of thetermination is in communication at 112 with the surrounding

casing chambers

62 and 115. This control of the liquid dielectric coolant is obtained through structuralfeatures by. which the casing and the line termination are so intertted and combined with one another, with the receptacle.Rand,.with the liquid circulating means comprising the pump Sand the conduits or

tubes

22, 24, 27| and 28. thatthe termination body 45 constitutes, in effect, a partition or barrier across the path of the circulating liquid.

In flowing axially through the annular dielectric space of the termination the liquid dielectric coolant is maintained in a path closely surrounding the resistive inner lm conductor 40 so as to maintain the form of a tubular sheath and a relatively high flow velocity over the surface of such resistor by a tubular guide 118 which surrounds the inner conductor in coaxial relation. An annular passage of substantially uniform'circular cross section is thus delineated throughout the major portion ofthe length of the resistive film conductor 40. Since the coolant flow confining guide 118 is disposed in the dielectric space of the termination T and in the electrical' field of the line, it is formed of a suitable dielectric material such as a plastic like polytetra-uoroethylene or, as here shown, of glass, preferably the familiar heat resistant Pyrex glass or equivalent having the desired low coeiiicient of thermal expansion. At its end adjacent the small end of the termination T the glass guide 118 is telescoped into a counterbore in a plastic collar 120 which fits the internal tapered contour of the outer conductor 42 over an annular area of contact between the parts.

At its upper end the tubular glass guide 118 is formed with an integral flared end or trumpet-shaped portion which has a peripheral edge received in an annular rabbet of a locating and sealing ring 127 formed of suitable plastic material such as polytetrailuoroethylene. The perihery of the sealing ring has a snug lit with the internal cylindrical surface of the connector tube 50, which thus locates lthe upper or ilared end of the glass guide in coxial relation to the termination conductors.

The structure of the present invention provides for optional removal and replacement of the inner conductor assembly without disturbing the outer conductor assembly and without even drainingor removing the liquid dielectric coolant from the casing C. To effect such removal, the main coaxial transmission line comprising the inner and outer conductors 71 and 72 previously mentioned in connection with Fig. 1 is first disconnected from the terminal end of the connector tube 50 and the socket or cup of the inner terminal element 73 so as to ydisconnect the device or instrument from the signal generator. Tlhe interlock and grip between the insulator block `60 and the terminal element 73 being released as described in the parentapfplication referred to, the inner conductor assembly is no longer held against relative turning or relative axial movement by the insulating vblock 60 and can be withdrawn bodily from within the outer conductor assembly, the inner conductor structure or assembly being lifted vertically in this operation. The bore in the insulating block 60 is, of course, slightly larger in diameter than the withdrawn parts such las the resistive coating 40 on the cylindrical ceramic tube 41 iand the. terminal band on the lower end of the inner 7 conductor so that these parts may be withdrawn axially through the insulation block 60 in lifting the inner conductor assembly up and out through the top of the connector tube 50 while the insulating block 60 remains permanently assembled and secured in the latter. Replacement of the same or a duplicate substitute inner conductor assembly is effected by lowering it through the bore in the insulator 60.

The termination T can be used to absorb lthe energy from Va high frequency electrical signal generator such as a television transmitter, functioning in such use as a so-called dummy load, and combined withv a suitable signal responsive system including a detector connected and arranged, say, to sample the wave signal from the transmitter in accordance with the principles set forth in the copending applications for patents referred to above, particularly Serial No. 116,318, led 17 September 1949. An instrument such as a voltmeter or wattmeter is thus provided to indicate voltage or power present at or being fed into the termination. When such an instrument is desired employing, say, a currentA sampler or voltage sampler, a pickup device or detector D, like the unit assmbly D described in copending application Serial No. 99,474 filed 16 .Tune 1949, which is part of a voltage divider, is combined with the termination T so that the parts function together in accordance with the principles described in 'the applications referred to.

When effecting the present combination of the detector or current sampling device D with the termination T certain advantageous results have been obtained, in that detector D in the form of a so-called combined capacitance voltage divider and crystal cartridge assembly is mounted on the casing C rather than on the tapering transition section or other conductor of the coaxial line. The present mounting permits removal and replacement of the inner conductor assembly as described above without disturbing the detector or voltage divider unit D and also locates the axis of pickup probe 132 substantially at or closely adjacent the plane of the juncture between the resistive film conductor 40 on the ceramic tube 41 and the plated on or metal paint contact band 67, with attendant improvement in accuracy of the instrument. The internal structure of the detector cartridge unit D is essentially the same as that of the corresponding unit in the patent application Serial No. 99,474 referred to and detailed disclosure is omitted here to avoid duplication. The unit includes a chambered body member 70 of brass or similar metal whiclh corresponds to the body 70 in the patent application of reference. In the present arrangement, however, the body 70 is formed with or has secured thereto a cylindrical pilot extension 133 which surrounds and is coaxial to the body opening through which probe 132 and plastic cap 134 project from the internal chamber of the detector body 70. A flat mounting plate 135 is formed with a central aperture which receives the cylindrical extension 133 of the body 70 and is abutted against a shoulder of the latter. The plate is secured to the body 70 and to the cylindrical extension 133 as by brazing or soldering.

A circular opening 137 to receive the pilot extension 133 is formed through the wall of the casing 1, through the reinforcing band or ring 47, and through the telescoped body 4S and connector section 44 of the termination outer conductor. This opening through the juxtaposed parts is of such size as to provide a sliding fit with the pilot extension 133 received therein, the pilot thus keying the parts together and preventing both rotative and axial movement of the termination T relative to the casing C and making full circular electrical contact with the conductive surface of the outer conductor connector 44. Rubber O-ring 136 is received in a circular groove formed in the external cylindrical surface of the extension 133 and engages the wall of the circular opening through the casing toseal `such opening and prevent loss of liquid dielectric coolant therethrough. `A

fiat spot face 138 on the outside of the casing body 1 about the opening 137 receives the mounting plate 135, the latter being attached Ito the casing as by screws 139 threaded into tapped holes that extend into the reinforcing ring 47. Within the body 70 is the tree structure described in the patent application Serial No. 99,474 referred to. It includes the adjustable length probe 132 which is insulated from the body and covered or enclosed by the plastic cylindrical cup 134, the latter sealing the opening intol the chamber of the detector body 70 to prevent liquid dielectric coolant in the casing C from entering the interior of the detector or sampling unit D. The condenser element of the detector unit tree structure (not shown) extends into a cylindrical metal capj or lateral extension 140 on the body 70, this extension being diametrically opposite tubular extension or sleeve 1.41 formed on or secured in the body 70 to receive and mount in removable and interchangeable relation a crystal rectifier unit 142. The condenser element 140 and the crystal unit 142 are on a common axis which parallels the axis of the casing C and a connector terminal 144 of the detector unit D is provided on one side of the body 70 for connecting the detector or voltage sampling assembly D through a two conductor coaxial cable 145 to a sensing element G in the form of a DArsonval galvanometer or the like.

The present invention thus provides a novel apparatus for terminating a coaxial transmission line in combination with a specialized branch line structure providing a unique arrangement by means of which high frequency energy from a coaxial transmission line may be detected or sampled substantially in the plane of the entering end of the termination.

In accordance with the patent statutes the principles of the present invention may be utilized in various ways, numerous modifications and alterations being contemplated, substitution of parts and changes in construction being resorted to as desired, it being understood that the embodiment shown in the drawings and described above is given merely for purposes of explanation and illustration without intending to limit the scope of the claims to the specific details disclosed.

What we claim and desire to secure by Letters Patent of the United States is:

1. In a high frequency electrical device of the character described, a casing, an inner conductor and an outer conductor arranged as a coaxial line and disposed within the casing, the outer conductor having a sliding fit in the casing for relative axial movement, and a pickup assembly mounted on the casing, said assembly comprising a body disposed generally on the outside of the casing and having an extension projected through and closely fitted in both the casing and the outer conductor to locate the casing and the conductor in predetermined relation.

2. In a high frequency electrical device of the character described, a casing having an opening at one end, an inner conductor and an outer conductor arranged as a coaxial line and received within the casing, the outer conductor having a sliding fit in the casing, thev outer conductor and the casing being formed with aligned apertures, a pickup assembly mounted on the casing, said assembly comprising a body disposed generally on the outside of the casing and having an extension projected `through and closely fitted in both the aligned apertures of the casing and the outer conductor to locate the casing and the conductor in predetermined relation, and closure means disposed across said casing opening.

3. In a high frequency electrical meter ofthe type comprising an attenuating coaxial line section having tubular outer conductor means andresistive inner conductor means/separated by an annular dielectric space, elongated hollow casing means having an opening at one end, said casing means being adapted to receive vandenclose the entire length of the line section for facile removal and replacement through said opening from and to a predetermined inserted position, the casing means and the outer conductor means being formed for close fitting sliding engagement one within the other in an axially limited zone, aligned radial openings in the outer conductor means and the casing means, a hollow pickup body having a circular sectioned extension portion, said pickup body being secured on the outside of the casing means over said aligned openings with the extension portion projected into such openings in closely fittingrelation and locating the line section in said predetermined position relative to the casing means, and probe means carried by the pickup body and projecting into the dielectric space through said ex-tension portion.

4. In a high frequency electrical meter as defined in claim 3, the outer conductor means of the line section comprising a tapered horn conductor having its larger end at the close fitting zone.

5. In a high frequency electrical meter as defined in claim 4, the outer conductor means of the line section comprising a circular sectioned connector tube and means having a flared conductive surface continuous with the internal surface of the tube and disposed with its larger inner end at the close fit-ting zone.

6. In a high frequency electrical meter as defined in `claim 5, the larger end of the horn conductor and the larger inner end of the flared conductive surface being in axially spaced planes, and the axis of the probe being located between said spaced planes.

7. In a high frequency electrical meter as defined in claim 5, the casing means including a casing tube and a reinforcing band inside such casing tube at the close fitting zone and the fiared means having a cylindrically curved peripheral surface slidingly engaging the reinforcing band.

8. In a high frequency electrical meter as defined in claim 4, the outer conductor means of the line section comprising a circular sectioned connector body having a fiared internal surface and a cylindrical external surface slidingly engaging the casing means in the close fitting zone and the larger end of the horn conductor being secured within the connector body and supported thereby.

9. In a high frequency electrical meter as defined in claim 3, the casing means including a casing tube and a reinforcing band insideV such casing tube at the close fitting zone.

10. In a high frequency electrical meter as defined in claim 9, the pickup body including a mounting plate disposed against the outside of the casing means, and fasteners extending through such plate, through the casing tube and securing the plate to the reinforcing band.

11. In a high frequency electrical meter as defined in claim 9, the outer conductor means of the line section comprising a circular sectioned connector body having a flared internal surface and a cylindrical external surface slidingly engaging the reinforcing band of the casing means in the close fitting zone, the outer conductor means of the line section comprising a tapered horn conductor having its larger end at the close fitting zone and including at said larger end an integral cylindrical portion, said connector body including an internal cylindrically curved surface, and the cylindrical portion of the horn conductor being received telescopically within the cylindrically curved surface of the connector body.

l2. In a high frequency electrical meter as defined in claim ll, the aligned radial openings being formed through the casing tube, the reinforcing band, the connector body and the cylindrical portion of the horn conductor.

13. In a high frequency electrical meter as defined in claim 3, the pickup body including a mounting plate disposed against the outside of the casing means, and fasteners extending through such plate and securing it to.

the casing means.

14. In a high frequency electrical meter as defined in claim 13, the mounting plate having a fiat surface, the casing means being generally of circular section and having a localized fiat area surrounding the radial opening, and the fiat surface of the mounting plate being disposed against the flat area of the casing means.

15. In a high frequency electrical meter as defined in claim 3, a body of liquid dielectric in the casing means and immersing the line section conductors, and a resilient O-ring seal embracing the extension of the pickup body and disposed in engagement with the casing means.

16. In a high frequency electrical meter as defined in claim 3, a body of liquid dielectric in the casing means and immersing the line section conductors, and a dielectric cup carried by the extension of the pickup and enclosing the probe.

17. In a high frequency electrical meter as defined in claim 3, the close fitting zone being spaced from both ends of the casing means.

18. In a high frequency electrical meter as defined in claim 3, the outer conductor means of the line section comprising a circular sectioned connector body having a flared internal surface and a cylindrical external surface slidingly engaging the casing means in the close fitting zone.

References Cited in the file of this patent UNITED STATES PATENTS 2,752,572 Bird et al. June 26, 1956 2,844,792 Bird et al. July 22, 1958