Abstract:
Axially compressible, F-connectors for conventional installation tools for interconnection with coaxial cable include adaptations for establishing electrical continuity despite inadequate nut tightening. Each connector has a rigid nut, a post penetrating the nut, a tubular body, and an end cap. The conductive post coaxially extends through the connector, linking the nut and body. A post end penetrates the coaxial cable. The connector may have a circumferential groove defined in the end cap mounting an annular D-ring which tensions contact between the post and nut. The connector may comprise a continuity coil seated within a post groove in spring-loaded contact with the nut and the post for promoting continuity. The connector may comprise a pressure spring and an O-ring seated within a post groove in spring-loaded contact with the nut for promoting continuity.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to coaxial cable connectors. More particularly, the present invention relates to coaxial F-connectors adapted to insure the establishment of a proper ground during installation. Known prior art is classified in United States Patent Class 439, Subclasses 241, 247, 322, 548, 553, 554, 585, and 587. 
     2. Description of the Related Art 
     Popular cable television systems and satellite television receiving systems depend upon coaxial cable for distributing signals. As is known in the satellite TV arts, coaxial cable in such installations is terminated by F-connectors that threadably establish the necessary signal wiring connections. The F-connector forms a “male” connection portion that fits to a variety of receptacles, forming the “female” portion of the connection. 
     F-connectors include a tubular post designed to slide over coaxial cable dielectric material and under the outer conductor at the prepared end of the coaxial cable. The exposed, conductive sheath is usually folded back over the cable jacket. The cable jacket and folded-back outer conductor extend generally around the outside of the tubular post and are typically coaxially received within the tubular connector. A continuity contact between the sheath and the conductive portions of the connector is needed. Moreover, electrical contact must be made with the threaded head or nut of the connector that should contact the female socket to which the connection is made. 
     F-connectors have numerous advantages over other known fittings, such as RCA, BNC, and PL-259 connectors, in that no soldering is needed for installation, and costs are reduced as parts are minimized. For example, with an F-connector, the center conductor of a properly prepared coaxial cable fitted to it forms the “male” portion of the receptacle connection, and no separate part is needed. A wide variety of F-connectors are known in the art, including the popular compression type connector that aids in rapid assembly and installation. Hundreds of such connectors are seen in U.S. Patent Class 439, particularly Subclass 548. 
     However, the extremely high bandwidths and frequencies distributed in conjunction with modern satellite installations necessitates a variety of strict quality control factors. For example, the electrical connection established by the F-connector must not add electrical resistance to the circuit. It must exhibit a proper surge impedance to maintain a wide bandwidth, in the order of several Gigahertz. Numerous physical design requirements exist as well. For example, connectors must maintain a proper seal against the environment, and they must function over long time periods through extreme weather and temperature conditions. Requirements exist governing frictional insertion and disconnection or withdrawal forces as well. 
     Importantly, since a variety of coaxial cable diameters exist, it is imperative that satisfactory F-connectors function with differently sized cables, such as RG-6 and RG-59 coaxial cables that are most popular in the satellite television art. 
     It is important to establish an effective electrical connection between the F-connector, the internal coaxial cable, and the terminal socket. Proper installation techniques require adequate torquing of the connector head. In other words, it is desired that the installer appropriately tighten the connector during installation. A dependable electrical grounding path must be established through the connector body to the grounded shield or jacket of the coaxial cable. Threaded F-connector nuts should be installed with a wrench to establish reasonable torque settings. Critical tightening of the F nut to the threaded female socket or fixture applies enough pressure to the inner conductor of the coaxial cable to establish proper electrical connections. When fully tightened, the head of the tubular post of the connector directly engages the edge of the outer conductor of the appliance port, thereby making a direct electrical ground connection between the outer conductor of the appliance port and the tubular post; in turn, the tubular post is engaged with the outer conductor of the coaxial cable. 
     Many connector installations, however, are not properly completed. It is a simple fact in the satellite and cable television industries that many F-connectors are not appropriately tightened by the installer. The common instillation technique is to torque the F-connector with a small wrench during installation. In some cases installers only partially tighten the F-connector. Some installations are only hand-tightened. As a consequence, proper electrical continuity may not be achieved. Such F-connectors will not be properly “grounded,” and the electrical grounding path can be compromised and can become intermittent. An appropriate low resistance, low loss connection to the female target socket, and the equipment connected to it, will not be established. Unless an alternate ground path exists, poor signal quality, and RFI leakage, will result. This translates to signal loss or degradation to the customer. 
     U.S. Pat. No. 3,678,445 issued Jul. 18, 1972 discloses a shield for eliminating electromagnetic interference in an electrical connector. A conductive shielding member having a spring portion snaps into a groove for removably securing the shield. A second spring portion is yieldable to provide electrical contact between the first shell member and a second movable shell member. 
     U.S. Pat. No. 3,835,442 issued Sep. 10, 1974 discloses an electromagnetic interference shield for an electrical connector comprising a helically coiled conductive spring interposed between mating halves of the connector. The coiled spring has convolutions slanted at an oblique angle to the center axis of the connector. Mating of the connector members axially flattens the spring to form an almost continuous metal shield between the connector members. 
     U.S. Pat. No. 3,739,076 issued Jun. 12, 1973 discloses a coaxial connector with an internal, electrically conductive coil spring is mounted between adjacent portions of the connector. As an end member is rotatably threaded toward the housing, an inwardly directed annular bevel engages the spring and moves it inwardly toward an electrically shielded portion of the cable. The spring is compressed circumferentially so that its inner periphery makes electrical grounding contact with the shielded portion of the cable. 
     U.S. Pat. No. 5,066,248 issued Nov. 19, 1991 discloses coaxial cable connector comprising a housing sleeve, a connector body, a locking ring, and a center post. A stepped annular collar on the connector body ensures metal-to-metal contact and grounding. 
     U.S. Pat. No. 4,106,839 issued Aug. 15, 1978 shows a coaxial connector with a resilient, annular insert between abutting connector pieces for grounding adjacent parts. A band having a cylindrical surface is seated against an internal surface. Folded, resilient fingers connected with the band are biased into contact. The shield has tabs for mounting, and a plurality of folded integral, resilient fingers for establishing a ground. 
     U.S. Pat. No. 4,423,919 issued Jan. 3, 1984 discloses a connector with having a cylindrical shell with radial flange, a longitudinal key, and a shielding ring fitted over the shell and adjacent to the flange. The shielding ring comprises a detent having end faces configured to abut connector portions when the detent fits within the keyway, whereby the shell is prevented from rotating. 
     U.S. Pat. No. 4,330,166 issued May 18, 1982 discloses an electrical connector substantially shielded against EMP and EMI energy with an internal, conductive spring washer seated in the plug portion of the connector. A wave washer made from beryllium copper alloy is preferred. 
     U.S. Pat. No. 6,406,330 issued Jun. 18, 2002 employs an internal, beryllium copper clip ring for grounding. The clip ring forms a ground circuit between a male member and a female member of the electrical connector. The clip ring includes an annular body having an inner wall and an outer wall comprising a plurality of circumferentially spaced slots. 
     U.S. Pat. No. 7,114,990 issued Oct. 3, 2006 discloses a coaxial cable connector with an internal grounding clip establishing a grounding path between an internal tubular post and the connector. The grounding clip comprises a C-shaped metal clip with an arcuate curvature that is non-circular. U.S. Pat. No. 7,479,035 issued Jan. 20, 2009 shows a similar F-connector grounding arrangement. 
     U.S. Pat. No. 7,753,705 issued Jul. 13, 2010 discloses an RF seal for coaxial connectors that makes a uniform RF seal. The seal comprises a flexible brim, a transition band, and a tubular insert with an insert chamber defined within the seal. In a first embodiment the flexible brim is angled away from the insert chamber, and in a second embodiment the flexible brim is angled inward toward the insert chamber. A flange end of the seal makes a compliant contact between the port and connector faces when the nut of a connector is partially tightened, and becomes sandwiched firmly between the ground surfaces when the nut is properly tightened. U.S. Pat. No. 7,892,024 issued Feb. 22, 2011 shows a similar grounding insert for F-connectors. 
     U.S. Pat. No. 7,824,216 issued Nov. 2, 2010 discloses a coaxial connector comprising a body, a post including a flange having a tapered surface, a nut having an internal lip with a tapered surface, which oppositely corresponds to the tapered surface of the post when assembled, and a conductive O-ring between the post and the nut for grounding or continuity. Similar U.S. Pat. Nos. 7,845,946 issued Dec. 7, 2010 and 7,892,005 issued Feb. 22, 2011 use conductive, internal O-rings for both grounding and sealing. 
     U.S. Pat. Nos. 6,332,815 issued Dec. 25, 2001 and 6,406,330 issued Jun. 18, 2002 utilize clip rings made of conductive resilient material such as beryllium copper for grounding. The clip ring forms a ground between a male member and a female member of the connector. 
     U.S. Pat. No. 6,716,062 issued Apr. 6, 2004 discloses a coaxial cable F connector with an internal coiled spring that establishes continuity. The spring biases the nut toward a rest position wherein not more than three revolutions of the nut are necessary to bring the post of the connector into contact. 
     For an adequate design, structural improvements to compressible F-connectors for improving continuity or grounding must function reliably without degrading other important connector requirements. Compressible connectors must adequately compress during installation without excessive force. An environmental seal must be established to keep out water. The coaxial cable inserted into the connector must not be mechanically broken an short circuited during installation. Field installers and technicians must be satisfied with the ease of installation. Finally, the bottom line is that a reliable installation must result for customer satisfaction. 
     BRIEF SUMMARY OF THE INVENTION 
     Our coaxial cable connectors are of the compressible type. The connectors comprise a rigid nut with a faceted drive head adapted to be torqued during installation of a fitting. The head has an internally threaded, tubular stem, for threadably mating with a typical socket or receptacle. An elongated post coupled to the nut includes a shank, which can be barbed, that engages the prepared end of a coaxial cable. An elongated, tubular body is coupled to the post. When the device is compressed, an end cap is press fitted to the body, coaxially engaging a body shank portion and closing the fitting. 
     In known F-connector designs the internal post establishes electrical contact between the coaxial cable sheath and metallic parts of the coaxial fitting, such as the nut. Also, the elongated, tubular shank extends from the post to engage the coaxial cable, making contact with the metallic, insulative sheath. 
     However, since improper or insufficient tightening of the nut during F-connector installation is so common, and since continuity and/or electrical grounding suffer as a result, our design includes adaptations that establish redundant grounding paths. All embodiments of our grounding insert include means for encouraging electrical contact between the nut, the post and thus the sheath of the coaxial cable to which the fitting is fastened. 
     In one embodiment of the invention, a circumferential groove is defined in the end cap in the outer face of the stop ring. This groove faces the nut. An annular, generally circular D-ring seated within the groove contacts the nut to tension the contact between it and the post. The resultant pressure maintains continuity between the post and nut. 
     A second embodiment uses a continuity coil formed from an elongated spring that is deformed into a circle. The coil is seated within the post groove between the post flanges, in spring-loaded contact with both the nut and the post. Electrical contact and continuity is thus established. 
     A third embodiment includes both a continuity coil and a D-ring. 
     The fourth embodiment includes a continuity coil, and an O-ring for sealing that is disposed upon a modified post. 
     The fifth embodiment uses a pressure spring and a contact washer in place of a D-ring within a groove in the body. 
     Electrical contact between the insert, the post, the nut, and the coaxial cable is thus insured, despite insufficient tightening of the nut. 
     Thus the primary object of our invention is to provide suitable grounding within an F-connector to overcome electrical connection problems associated with improper installation. 
     More particularly, an object of our invention is to provide dependable electrical connections between coaxial connectors, especially F-connectors, and female connectors or sockets. 
     Another object of the present invention is to provide internal structure for establishing a grounding path in an improperly-tightened coaxial cable connector. 
     A similar object is to provide a proper ground in a coaxial connector, even though required torque settings have been ignored. 
     Another related object of the present invention to provide a reliable ground connection between a connector and a target socket or port, even if the connector is not fully tightened. 
     It is another object of the present invention to provide such a coaxial cable connector which establishes and maintains a reliable ground path. 
     It is still another object of the present invention to provide such a coaxial connector that can be manufactured economically. 
     Another object of our invention is to provide a connector of the character described that establishes satisfactory EMP, EMI, and RFI shielding. 
     A related object is to provide a connector of the character described that establishes a decent ground during installation of the male connector to the various types of threaded female connections, even though applied torque may fail to meet specifications. 
     Another essential object is to establish a proper ground electrical path with a socket even where the male connector is not fully torqued to the proper settings. 
     Another important object is to minimize resistive losses in a coaxial cable junction. 
     A still further object is to provide a connector suitable for use with demanding large, bandwidth systems approximating three GHz. 
     A related object is to provide an F-connector ideally adapted for home satellite systems distributing multiple, high definition television channels. 
     Another important object is to provide a connector of the character described that is weather proof and moisture resistant. 
     Another important object is to provide a compression F-connector of the character described that can be safely and properly installed without deformation of critical parts during final compression. 
     These and other objects and advantages of the present invention, along with features of novelty appurtenant thereto, will appear or become apparent in the course of the following descriptive sections. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       In the following drawings, which form a part of the specification and which are to be construed in conjunction therewith, and in which like reference numerals have been employed throughout wherever possible to indicate like parts in the various views: 
         FIG. 1  is a frontal isometric view of a typical coaxial connector in which the adaptations of our invention are incorporated; 
         FIG. 2  is a rear isometric view of the connector of  FIG. 1 ; 
         FIG. 3  is an exploded, longitudinal sectional view of a connector of the type seen in  FIGS. 1 and 2 , in which the first embodiment of our grounding adaptation has been incorporated; 
         FIG. 4  is an enlarged, longitudinal sectional view of the connector of  FIG. 3 ; 
         FIG. 5  is an enlarged end view of the D-ring employed within the connector of  FIGS. 3 and 4 ; 
         FIG. 6  is an enlarged, elevational view of the D-ring employed within the connector of  FIGS. 3 and 4 ; 
         FIG. 7  is an exploded, longitudinal sectional view of a connector of the type seen in  FIGS. 1 and 2 , in which the second embodiment of our grounding adaptation has been incorporated; 
         FIG. 8  is an enlarged, longitudinal sectional view of the connector of  FIG. 7 ; 
         FIG. 9  is an enlarged end view of the continuity coil employed within the connector of  FIGS. 7 and 8 ; 
         FIG. 10  is an enlarged, elevational view of the continuity coil employed within the connector of  FIGS. 7 and 8 ; 
         FIG. 11  is an exploded, longitudinal sectional view of a connector of the type seen in  FIGS. 1 and 2 , in which the third embodiment of our grounding adaptation has been incorporated; 
         FIG. 12  is an enlarged, longitudinal sectional view of the connector of  FIG. 11 ; 
         FIG. 13  is an exploded, longitudinal sectional view of a connector of the type seen in  FIGS. 1 and 2 , in which the fourth embodiment of our grounding adaptation has been incorporated; 
         FIG. 14  is an enlarged, longitudinal sectional view of the connector of  FIG. 13 ; 
         FIG. 15  is an enlarged end view of the O-ring employed within the connector of  FIGS. 13 and 14 ; 
         FIG. 16  is an enlarged, elevational view of the D-ring employed within the connector of  FIGS. 13 and 14 ; 
         FIG. 17  is a longitudinal sectional view of a connector of the type seen in  FIGS. 1 and 2 , in which the fifth embodiment of our grounding adaptation has been incorporated; 
         FIG. 18  is an enlarged end view of the O-ring employed within the connector of  FIG. 17 ; 
         FIG. 19  is an enlarged, elevational view of the O-ring employed within the connector of  FIGS. 17 and 18 ; 
         FIG. 20  an enlarged elevational view of the pressing spring employed within the connector of  FIGS. 17-19 ; and, 
         FIG. 21  an enlarged end view of the pressing spring employed within the connector of  FIGS. 17-20 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Coaxial cable F-connectors are well known in the art. The basic constituents of the compressible coaxial connector of  FIGS. 1 and 2  are described in detail, for example, in prior U.S. Pat. No. 7,841,896 entitled “Sealed compression type coaxial cable F-connectors”, issued Nov. 30, 2010, and in prior U.S. Pat. No. 7,513,795, entitled “Compression type coaxial cable F-connectors”, issued Apr. 7, 2009, which are both owned by the same assignee as in the instant case, and which are both hereby incorporated by reference for purposes of disclosure as if fully set forth herein. However, it will be appreciated by those with skill in the art that coaxial cable connectors of other designs may be employed with the grounding adaptations described hereinafter. 
     Referring initially to  FIGS. 1-4  of the appended drawings, a coaxial F-connector has been generally designated by the reference numeral  20 . As will be recognized by those skilled in the art, connector  20  is a compressible F-connector, that is axially squeezed together longitudinally when secured to a coaxial cable. As is also recognized in the art, connector  20  is adapted to terminate an end of a properly prepared coaxial cable, which is properly inserted through the open bottom end  22  of the connector  20 . Afterwards, the connector is placed within a suitable compression hand tool for compression, assuming the closed configuration of  FIGS. 1 and 2  and making electrical contact with the cable. 
     Connector  20  comprises a rigid, tubular, metallic nut  24  with a conventional faceted, preferably hexagonal drive head  26  integral with a protruding, coaxial stem  28 . Nut  24  is torqued during installation. Conventional, internal threads  30  are defined in the stem interior for rotatably, threadably mating with a suitably-threaded socket. The open, tubular front end  21  connects through the open interior to a reduced diameter rear passageway  34  at the back of nut  24  ( FIG. 3 ). Circular passageway  34  concentrically borders an annular, non-threaded, internal ring groove  36  that borders an internal shoulder  37  proximate passageway  34 . 
     An elongated post  40  rotatably, coaxially passes through the hex headed nut  24 . In most F-connector designs the metallic post  40  establishes electrical contact between the braid of the coax and the metallic nut  24 . The tubular post  40  defines an elongated shank  41  with a coaxial, internal passageway  42  extending between its front  43  and rear  44 . Shank  41  may or may not have barbs formed on it for engaging coaxial cable. A front, annular flange  46  ( FIG. 3 ) is spaced apart from an integral, reduced diameter flange  48 , across a ring groove  50 . A conventional, resilient O-ring  52  is optionally seated within post ring groove  50  when the connector  20  is assembled. O-ring  52  is preferably made of a silicone elastomer, and its function is to provide a moisture seal. 
     Preferably the post  40  has a barbed, collar  54  comprising multiple, external barbs  56  that are press fitted into the plastic body  60  described below. In assembly it is noted that post flange  46  (i.e.,  FIGS. 3 ,  4 ) axially contacts inner shoulder  37  ( FIG. 3 ) within nut  24 . Inner post flange  48  and the O-ring  52  are coaxially, frictionally disposed within passageway  34  at the rear of nut  24 . 
     The rear, tapered end  44  of post shank  41  penetrates the prepared end of the coaxial cable, such that the inner, insulated coaxial cable conductor coaxially penetrates passageway  42  and enters the front  21  of the nut  24 . Concurrently, the braided shield of the coax is positioned around the exterior of post shank  41 , making electrical contact, hopefully establishing a good ground, or continuity between the coaxial cable sheath, the post  40 , and the nut  24 . 
     An elongated, hollow, tubular body  60 , normally molded from plastic, is coupled to the post  40 . Body  60  preferably comprises a tubular stop ring  62  that is integral with a reduced diameter body shank  64 . The elongated, outer periphery  66  of shank  64  is smooth and cylindrical. The larger diameter stop ring  62  has an annular, rear wall  63  that is coaxial with shank  64 . Ring  62  defines an internal passageway  70  through which the post  40  is inserted. In assembly, the barbed post collar  54  is frictionally seated within body passageway  70 . 
     An end cap  76  is pressed unto body  60 , coaxially engaging the body shank  64 . The rigid, preferably metallic end cap  76  smoothly, frictionally grips body shank  64 , with maximum travel or displacement limited by stop ring  62 . In other words, when the end cap  76  is compressed unto the body  60 , and the connector  20  assumes a closed position (i.e.,  FIG. 2 ), annular wall  63  on the body stop ring  62  will limit axial deflection and travel of the end cap  76 . Preferably the open end  78  of the end cap includes internally barbed region  79  that couples to the shank  64  of the body  60 . When the body  60  and the cap  76  are compressed together, body travel is limited within cap passageway  82  by contact with internal cap shoulder  85 . The reduced diameter passageway  88  is sized to receive coaxial cable, which is inserted through the flared opening  89 . An outer ring groove  90  at the cap rear can seat a desired, external O-ring that can be added to establish a tactile “feel” for the installer, and/or to enhance the aesthetic appearance. 
     In most F-connectors, grounding or continuity is established by mechanical and electrical contact points between abutting, conductive, metallic parts. Noting  FIGS. 3 and 4 , for example, normal grounding should occur between internal nut shoulder  37  and post flange  46 . The coaxial cable sheath bearing against the post shank  41  would thus electrically interconnect with the post and the nut  24 , which would in turn establish electrical contact with the socket to which nut  24  is attached. However, grounding or continuity depend on proper tightening of the nut  24 . In the real world, installers often neglect to properly tighten the nut, so less internal, mechanical pressure is available within the F-connector to urge the parts discussed above into abutting, conductive contact. 
     First Embodiment 
     Therefore our electrical grounding adaptations have been proposed. The first embodiment of our adaptation includes a circumferential groove  100  defined in the body  60  illustrated in  FIGS. 3 and 4 . Groove  100  is coaxially defined in the outer face of stop ring  62  and, in assembly, faces the nut  24 . An annular, generally circular D-ring  102  (i.e., resembling an O-ring) is pressed into groove  100 , and, in assembly contacts the nut  24 . The cross section of the O-ring reveals a generally band-like, tubular body  104  ( FIG. 5 ) with a forward end  106  with a radiused profile, and a flat rear  105 . Thus the preferred O-ring is in the form of a D-ring. 
     D-ring  102  presses forward on the F-connector nut  24  with resulting, positive pressure being maintained to tension the contact between post flange  46  and the inner nut shoulder  37  when the nut rotates around the connector during installation. This positive pressure maintains a constant continuity connection between the post and F nut. D-ring  102  also provides a secondary function as a moisture barrier. 
     Second Embodiment 
     A second or alternative embodiment is seen in  FIGS. 7-10 . Alternative F-connector  23 , is externally substantially identical with connector  20 , discussed above. However, connector  23  includes a continuity coil described hereinafter instead of O-ring  52 . Like connector  20 , the alternative connector  23  comprises a nut  24 , a post  40 , a body  60 B, and an end cap  76 , all of which are described above. Body  60 B, however, lacks a groove  100 . 
     As best viewed in  FIGS. 9 and 10 , the continuity coil  110  resembles an O-ring, such as O-ring  52  ( FIG. 3 ) of the last described embodiment. The coil  110  is made of a looped, length of spring wire  114 . The body has a circular cross section, indicated by the reference numeral  115  ( FIG. 9 ). Coil  110  sits within post groove  50 , and frictionally contacts the peripheral, surrounding wall of passageway  34  in the nut  24 , that radially surrounds it. At the same time, post flange  46  contacts nut shoulder  37  ( FIG. 8 ). 
     Preferably, continuity coil  110  is made from phosphor bronze or a similar conductive metallic alloy. Coil  110  seats within post groove  50  ( FIG. 7 ). The outside diameter  117  ( FIG. 10 ) of the coil  110  is fractionally larger than the diameter of the passageway  34  in which it coaxially rests. The coil is therefore in a spring-load contact with both the threaded nut  24 , and the connector post  40 . Electrical contact and continuity is therefore assured, even if nut  24  is not fully torqued and seated against the mating female threaded connector. A less-than-perfect torque application of the but  24  during installation will not necessarily result in an electrical ground continuity failure with coil  110 . 
     Third Embodiment 
     A third embodiment is seen in  FIGS. 11-12 . Alternative F-connector  23 B, is externally substantially identical with connector  20 , discussed above. However, connector  23 B includes both a continuity coil  110  described above, and a D-ring  102 . Like connector  20 , the alternative connector  23 B comprises a nut  24 , a post  40 , a body  60  and an end cap  76 , all of which are described above. 
     D-ring  102  is nested within a groove  100  defined in the body  60  as described above. D-ring  102  functions upon assembly to tension the physical contact point between the post  40  and the nut  24 . Meanwhile, continuity coil  110 , seated within post groove  50  as before, contacts the periphery of nut passageway  34  and the surfaces bordering post groove  50  it establish electrical contact. 
     Fourth Embodiment 
     The fourth F-connector embodiment is seen in  FIGS. 13-15 . Alternative F-connector  23 D, is again externally similar to connector  20 , discussed above. However, connector  23 D includes both a continuity coil  110  described above, and an O-ring  152 . Like connector  20 , the alternative connector  23 D comprises a nut  24 , a body  60 B and an end cap  76 , all of which are described above. Post  40 B however, is different. 
     Like post  40 , post  40 B has a large flange  46  separated from an integral smaller flange  48  by a groove  50 . However, there is a shoulder  140  disposed between smaller flange  48  and the post&#39;s barbed collar  54 B. A circular O-ring  152  is seated upon post  40 B on shoulder  140 . As before, there is a continuity coil  110  seated within post groove  50  between flanges  46  and  48 . The continuity coil establishes a redundant ground path as discussed above, to insure continuity. The O-ring  152  is used to seal the connector  23 D, to repel moisture ingress. 
     Fifth Embodiment 
     A fifth embodiment seen in  FIGS. 17-19 . Alternative F-connector  23 E, is externally substantially identical with connector  20 , discussed above. However, connector  23 E substitutes the previously described D-ring  102  (i.e.,  FIG. 3 ) with a pressing O-ring  160  and a compression spring  164 . 
     Like connector  20 , the alternative connector  23 E comprises a nut  24 , a post  40 , a body  60  and an end cap  76 , and a groove  100  defined in the body, all of which are described above. 
     O-ring  160  ( FIGS. 18 ,  19 ) is nested within groove  100  defined in the body  60 , next to compression spring  164  ( FIGS. 20 ,  21 ). O-ring  160  has a square cross section, as seen in  FIG. 18 . The compression spring has a plurality of coiled windings, as seen in  FIG. 21 . Spring  164  and O-ring  160  have the same diameter, which is sized to fit these pieces within groove  100 . 
     Spring  164  functions upon assembly to tension the physical contact point between O-ring  160 , the post  40 , and the nut  24 . 
     From the foregoing, it will be seen that this invention is one well adapted to obtain all the ends and objects herein set forth, together with other advantages which are inherent to the structure. 
     It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. 
     As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.