Patent Publication Number: US-2022217327-A1

Title: Icon-based home certification, in-home leakage testing, and antenna matching pad

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/174,461, filed Oct. 30, 2018, which is a continuation of U.S. patent application Ser. No. 15/906,989, now U.S. Pat. No. 10,116,930, filed Feb. 27, 2018, which is a continuation of U.S. patent application Ser. No.  15 / 595 , 876 , now U.S. Pat. No. 10,110,888, filed May 15, 2017, which is a continuation of U.S. patent application Ser. No. 14/435,628, now U.S. Pat. No. 9,667,956, which was filed Apr. 14, 2015, and was a national stage entry under 35 U.S.C. § 371(b) of international Application No. PCT/US2013/064993, filed Oct. 15, 2013, which claimed the benefit under  35  U.S.C. § 119(e) of U.S. Ser. No. 61/713,707 filed Oct. 15, 2012, of U.S. Ser. No. 61/807,046 filed Apr. 1, 2013, U.S. Ser. No. 61/823,966 filed May 16, 2013, and of U.S. Ser. No. 61/862,716 filed Aug. 6, 2013, Each of the foregoing applications is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Currently, in the CATV (hereinafter sometimes cable) industry, technicians perform a series of tests at multiple points in a subscriber location before an installation is deemed “Quality” or “Clean.” This process is known as certification. It creates what is known as a “birth certificate” for the subscriber premises. The management of a multi-system operator (hereinafter sometimes MSO) or smaller cable system operator identifies certain system performance limits that must be passed in order to certify the subscriber location as ready for connection to the system. As an example, the operator&#39;s home certification program might require the operator&#39;s installation and service technicians to run tests at different points in the distribution circuit at the subscriber&#39;s location (for example, home, apartment building, or place of business) in a certain order with certain limits on the test results at each point. 
     Another problem is with cable systems switching to digital. Leakage from analog cable channels is readily detected by systems, generally referred to as “taggers,” of the general types illustrated in, for example, U.S. Pat. Nos. 5,608,428: 6,018,358; 6,804,826, and references cited therein. The disclosures of these references are hereby incorporated herein by reference. This listing is not ended to be a representation that a complete search of all relevant art has been made, or that no more pertinent art than that listed exists, or that the listed art is material to patentability. Nor should any such representation be inferred. 
     However, distinct from an analog channel, a digital channel signal is spread fairly uniformly over 6 MHz. As a result, there is too little “tag” signal power in any sample, or “slice,” of the 6 MHz digital signal to reliably render the tag signal detectable. 
     A solution to this problem of tagging digital signals is to put a single frequency tag signal in the gap between adjacent 6 MHz digital channels and then monitor the gap in an effort to detect the if the tag is detected, the operator has detected a leak. An enhancement puts multiple, for example, two, tag signals in the gap at multiple, for example, two, frequencies spaced far enough apart to discriminate between them. The operator looks for both/all of the inserted signals in order to detect a leak. The use of multiple tag signals at multiple different frequencies is useful where, for example, systems are overbuilt. Examples of these and similar techniques are described in, for example, PCT publication WO 2013/003301. Again, the disclosure of this reference is hereby incorporated herein by reference. This listing is not intended as a representation that a complete search of all relevant art has been made, or that no more pertinent art than that listed exists, or that the listed art is material to patentability. Nor should any such representation be inferred. 
     SUMMARY 
     A method for determining the magnitude of leakage in a subscriber&#39;s premises CATV installation comprises disconnecting the network at a suitable network port, coupling a frequency source to the port so that a high power offset is maintained, shielding the frequency source o prevent a signal level meter or leakage receiver from receiving radiated frequency source oscillations, transporting a signal level meter or leakage receiver around the premises. and logging signal levels measured by the signal level meter or leakage receiver as the signal level meter or leakage receiver is transported. 
     Illustratively, the method further comprises addressing excessive signal levels thus logged. 1095.0212US6 
     Illustratively, disconnecting the network at a suitable network port comprises disconnecting the network at the subscriber&#39;s premises ground block. 
     Illustratively, coupling a frequency source to the port comprises coupling; a dual oscillator to the port. 
     Illustratively, coupling a coupling a frequency source to the port so that a high power offset is maintained comprises coupling a dual oscillator to the port at a level in the range of about 40 dB to about 70 dB above the level provided by the network. 
     Illustratively, logging signal levels measured by the signal level meter or leakage receiver as the signal level meter or leakage receiver is transported comprises calculating GT from the equation 
     
       
      
       P 
       R 
       =P 
       T 
       −L 
       L 
       +G 
       T 
       −L 
       fs 
       +G 
       R  
      
     
     where P R =received power in dBmV;
     P T =transmitted power in dBmV;   L L =line loss in the port and the subscriber&#39;s premises internal cabling;   G T =gain in dBi of the transmitting antenna;   L fs =loss in dB attributable to the space between the leak and the receiving antenna; and   G R =gain in dBi of the receiving antenna.   

     Further illustratively, the method comprises analyzing the Measurement to ascertain the location and extent of the leak. 
     Further illustratively, the method comprises generating a work order to repair the leak responsible for the calculated G T . t 4 ) 0141  Further illustratively, the method comprises analyzing the measurement to ascertain the likelihood of interference from the premises entering the CATV system through the leak responsible for the calculated G T  and disrupting other CATV services. 
     Further illustratively, the method comprises analyzing the measurement to ascertain isolation between the CATV system and the premises. 
     Further illustratively, the method comprises providing the measurement to (a) server(s) operated by the CATV system operator, or to whose services the CATV system operator subscribes, and entering the measurement into the subscriber&#39;s file, along with the time(s) the measurement(s) was/were made, subscriber location/identity, and information about whether, and if so, when, a work order was filled. 
     Further illustratively, the method comprises entering the measurement into a management information base and generating from the management information base an alert concerning the status of one or more components or functions of the CATV plant. 
     Further illustratively the method comprises subtracting the power offset from the signal level, converting the result to a field strength and displaying the resulting field strength on, for example, a display associated with the signal level meter or leakage receiver. 
     A frequency multiplexer is provided for coupling between an antenna and a receiver for the multiplexed frequencies. The multiplexer divides a received frequency spectrum into at least a low band and a high band. The multiplexer includes a low pass filter (hereinafter sometimes LPF) for passing the low band from the antenna to the receiver and a high pass filter (hereinafter sometimes tiff) for passing the high band from the antenna to the receiver. The LW and HPF are coupled in parallel between an output port of the antenna and an input port of the receiver. 
     Illustratively, the LPF comprises first and second inductances coupled in series between the output port and the input port, and a first, capacitance coupled between the junction of the first and second inductances and the receiver ground. The HPF comprises second and third capacitances coupled in series between the output port and the input port and a third inductance coupled between the junction of the second and third capacitances and the receiver ground. 
     Further illustratively, the multiplexer comprises an antenna impedance matching network coupled between the output port and the LPF. 
     A method for a technician o certify a CATV subscriber&#39;s premises for the provision of CATV services comprises: (a) locating the CATV tap at the subscriber&#39;s premises; (b) coupling a certification instrument to the tap; (c) displaying on a display associated with the certification instrument a screen or image or picture or icon of a first test of the certification process; (d) executing the first test of the certification process, the display then advising the technician if the subscriber&#39;s premises passes or fails the first test; (e) displaying on the display a screen or image or picture or icon notifying the technician what test the technician needs to perform next; (f) executing the next test, the display then advising the technician if the subscriber&#39;s premises passes or fails the next test; ( 0  repeating steps (e) and (f) for as many additional tests as are necessary to complete the certification process; and, (h) transmitting certification testing results to a server maintained for this purpose. 
     Further illustratively, the method comprises: before step (a) issuing a certification work order; and, after step (g) closing out the certification work order. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by referring to the following detailed description and accompanying drawings which illustrate the invention. In the drawings: 
         FIGS. 1-8  illustrate steps of a screen- or image- or picture- or icon-guided process to be followed by a technician to perform a subscriber&#39;s premises certification of a CATV system connection; 
         FIG. 9  illustrates a method and apparatus for performing a subscriber&#39;s premises certification: and 
         FIGS. 10-18  illustrate a component useful with other equipment for performing a subscriber&#39;s premises certification, and plots of performance characteristics of the illustrated component. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     In subscriber premises certifications, currently operators issue certification work orders,  FIGS. 1, 2 . The technician arrives at the premises, certification of which is sought, locates the tap and executes the “Tap” macro,  FIGS. 3-5 , of the screen- or image- or picture- or icon-guided process of the invention. Once this step is complete, the screen- or image- or picture- or icon-guided process advises the technician if the tap passes or fails,  FIGS. 5-7 . At this time, the screen- or image- or picture- or icon-guided process also notifies the technician what test the technician needs to perform next. For example, the screen- or image- or picture- or icon-guided process may require the technician to move on to the cable drop and perform the “Drop” test measurements there, using the limits set for the “Drop.” Again, once this step is complete the screen- or image- or picture- or icon-guided process advises the technician if the drop passes or fails. At this time, the screen- or image- or picture- or icon-guided process also notifies the technician what test the technician needs to perform next. For example, the screen- or image- or picture- or icon-guided process may require the technician to move inside the subscriber&#39;s premises to the cable outlet(s) or customer premises equipment (CPE), and perform the autotest there,  FIG. 7 . Once these tests of the screen- or image- or picture- or -on-guided process are performed, the results are graded against the limits set for the outlet(s) or CPE. The technician then moves on to the final test at the ground block (hereinafter sometimes GB), Fig . Once the GB test is complete and the installation meets all the requirements, the technician is directed to close out the job and transmit the completed test documentation up to the server for system management purposes,  FIGS. 7-8 . 
     There are currently basically two available types of leakage gear. So-called “truck-mounted” units are mounted in vehicles that are driven along the cable plant, generally by maintenance/service technicians to monitor leakage along the cable. These systems are generally quite sophisticated and, as a result, expensive, costing in the range of $3000 or more. 
     With reference to  FIG. 9 , the second type of leakage gear is the type given to technicians who come into subscribers&#39; facilities  100  to hook up cable service and check connections initially. As a part of their installation process, sometime during the installation process the technicians walk around the house  100  with usually a fairly simple signal level meter (hereinafter sometimes SLM)  102  with an antenna  104  designed to receive signals in the cable  106  bandwidth. The presence of a signal in excess of a threshold is cause for further investigation that the cable  106  installation in the subscribers&#39; premises  100  may have a flaw that could result in egress of downstream-bound signal from the cable system or, perhaps equally as importantly, ingress of signal from the premises  100  into the cable system in the upstream-bound “return band.” The SLM  102 /antenna  104  combination is rather less sophisticated, and, as a result, rather less expensive, typically costing in the $300-$600 range. At this price point, technicians can he equipped with the SLM  102 /antenna  104  combination to check subscribers&#39; premises  100  for leaks during an installation. 
     In-premises leakage mitigation is very important to the successful operation of a cable system with modern, high-speed cable services. In-premises is part of the system that is not under direct control of the cable operator. As a result, things can and will happen, such as emissions and ingress, that can have a direct effect on the cable quality of service. Further, there are many new products, such as cell phones and cell-equipped tablets, which populate the premises which are sources of ingress and which can thus disrupt or degrade the quality of video or data. 
     The cable industry is always concerned about leakage from the cable plant. Up until a few years ago, the industry was mostly interested in the aeronautical band (about 138 MHz). More recently, with the cell phone providers&#39; introduction of 4G, the cable industry has also become concerned with the LTE band (about 750 MHz). For example, the Trilithic Seeker™ D instrument has the capability to monitor both of these bands using a diplexer (one combined output, two frequency separated inputs). This diplexer has a low band input in the range of about 138 MHz and a high band input in the range of about 750 MHz. This permits a vehicle to have two external antennas, one tuned to about 138 MHz and the other tuned to about 750 MHz, with their outputs combined through the diplexer and then input to an SLM in the truck. 
     However, when the technician takes his leakage-measuring instrument from the truck&#39;s mobile mount, the instrument is disconnected from the diplexer and dual antennas. While a portable diplexer with two antennas is not out of the question, this combination including the SLM, diplexer and two antennas, will be somewhat awkward for the technician to walk around. with, and somewhat difficult to use. in any attempt to use only one antenna to receive both frequencies, the mismatched frequency will be almost undetectable due to impedance mismatch loss and reflections. With reference to  FIGS. 10-18 , the illustrated antenna multiplexer permits a single antenna tuned for one frequency to work well at both frequencies. This antenna-multiplexing concept is readily adaptable to three, four, or more, frequencies. 
     The illustrated antenna multiplexer has a single input and a single output. The signal combining and matching networks are internal to the multiplexer. The different matching networks for each frequency of interest are combined in the multiplexer. 
     A monopole antenna matching pad (hereinafter sometimes MAMP, multiplexer or diplexer)  130  couples a monopole (rubber duck.) antenna  104  for receiving dual frequency leakage signal to a receiver meter or SLM  102 . The MAMP  130  is connected to the antenna  104  at a BNC (female) port  132 , and to the receiver meter or SLM  102 . at a BNC/F (male) port  134 . The resonant frequency of the antenna  104  is in the range of the upper frequency of interest, here about 750 MHz. 
     With reference to  FIG. 10 , the MAMP  130  includes a BNC (female) connector  132 , a piece  136  of beryllium copper, an enclosure body  138 , a BNC/F (male) connector  134  and a piece  140  of, for example, FR-4, PCB with two pins  142 ,  144  that couple to the center conductors of the BNC and F connectors  132 ,  134 , to form the center conductors of the BNC and F connectors  132 ,  134 . Assembly of the MAMP  130  is illustrated in  FIG. 11 . The illustrated MAMP  130  is a two port matched diplexer, in which a high pass filter comprising capacitors  146 ,  148  and inductor  150  provides a high frequency path to the SLM ( FIG. 10 )  102 , and a low pass filter comprising an inductor  152 , an inductor  154  and a capacitor  156  matched by an antenna impedance matching network comprising an inductor  158  and an inductor  160  to provide a low frequency path to the SLM  102  ( FIG. 14 ).  FIG. 13 . illustrates the schematic of the MAMP  130  when the antenna  104  is receiving high (operating/resonant) frequency signal. At this frequency, the antenna&#39;s source impedance is about 50 Ω.  FIG. 14  illustrates the frequency response of the MAMP in the region of the resonant frequency of the antenna  104 .  FIG. 15  illustrates the schematic of the MAMP  130  when the antenna  104  is receiving the low frequency signal. At this frequency, the antenna&#39;s source impedance is about 3 Ω in series with an approximately 18 pF capacitance.  FIG. 16  illustrates the frequency response of the MAMP in the region of the low frequency signal. 
     To make a reliable and inexpensive PCB assembly, the illustrated MAMP  130  PCB layout incorporates five printed inductors  150 ,  152 ,  154 ,  158  and  160  instead of coil inductors. As illustrated in  FIG. 17 , three printed inductors  158 ,  152 ,  154  of the LPF are on one side and a HPF  146 ,  148 ,  150 , LPF capacitor  162  and a printed matching inductor  160  are on the other side ( FIG. 18 ). 
     Among the advantages of the illustrated MAMP  130  are: one antenna  104  with MAMP  130  can receive multiple frequencies; the MAMP  130  provides 10 to 15 dB higher antenna gain at low frequency; the MAMP  130  readily connects to the antenna  104  and the SLM  102  for leakage testing; MAMP  130  adapts the antenna  104 &#39;s BNC connector  132  to the SLM  102 &#39;s F connector  134 ; the MAMP  130  structure takes advantage of existing construction techniques that provide; simple, easy assembly and reliable operation; and, MAMP  130  PCB layout reduces cost; provides better performance and permits easier matching tuning. 
     The monopole antenna  104  is coupled via BNC connector  132  through series inductors  158 ,  152  and  154  and BNC/F connector  134  to the SLM  102 . Inductor  160  is coupled between the common terminal of inductors  158  and  152  and SLM  102  ground. Capacitor  156  is coupled between the common terminal of inductors  152  and  154  and SLM  102 . ground. The series combination of capacitor  146  and capacitor  148  is also coupled between the BNC connector  132  and the BNC/F connector  134 . An inductor  150  is coupled between the common terminal of capacitors  146  and capacitor  148  and SLM  102  ground. When the low frequency is being measured, an additional capacitor is coupled between the antenna  104  and SLM  102  ground. In the previously discussed embodiment, in which the low frequency is about 138 MHz and the high frequency is about 757.5 MHz., the various component values may be, for example:  158  is about 46 nH;  160  is about 12.5 nH;  152  is about 40 nH;  154  is about 47 nH; L 5  is about 12 nH;  156  is about 18 pF;  146  is about 5.1 pF;  148  is about 5.1 pF; and, the capacitor between the antenna and SLM ground is about 18 pF ±2%. 
     In an illustrative embodiment, two CW test carriers at two frequencies are injected at the ground block with a defined relationship to the system levels at those frequencies. For example, if the normal operating system levels are +0 dBmV at the ground block  106 , the technician connects the test generator this point at +40 dBmV at both frequencies, for example, about 138 MHz (for example, about 139.2.5 MHz) and about 750 MHz (for example, about 757.5 MHz). This establishes a test signal level-to-system level relationship of 40 dB. These test signals propagate through the subscriber premises  100  in the same manner as the CATV signal, only at higher levels. Since these test levels are much higher, a very sensitive, and typically more expensive, SLM is not needed to detect the leakage. The economical SLM  102  includes a “rubber duck” antenna  104  frequency matched to capture the leakage as the SLM  102  is moved through the subscriber premises  100 . The SLM  102  is programmed to automatically account for the antenna factor and the fact that the test signal is, for example, 40 dB above system level, and to convert the thus-adjusted readings to microvolts per meter (μV/m) for display on SLM  102 . 
     One set of sensitivity tests with the system indicate leaks at about 138 MHz have a sensitivity of 1 μV/m @ +40 dB and 0.10 μV/m @ +60 dB. Leaks at about 750 MHz, have a sensitivity in the range of 4 μV/m @ +40 dB and 0.40 μV/m at +60 dB. These sensitivity ranges permit technicians to find even very small leaks which are capable of causing ingress or egress in cable, active cable elements, passive cable elements and customer premises devices (hereinafter sometimes CPD) units. Although these sensitivities are high, they should be immune to most noise-generated false readings as the elevated readings are generally well above ambient noise levels. This data can be appended to the premises “health” or premises certification test data for a subscriber installation and uploaded to a permanent record of that installation in system management software, such as Trilithic Viewpoint™ software. In instances where a full SLM  102  is not needed, a leakage receiver for “leakage-only” applications can be used. 
     Further considering ingress into a premises cable plant, shielding defects in premises wiring systems and customer premises equipment or customer-provided equipment (hereinafter both sometimes CPE) have the potential to collect and intermingle terrestrial signals with the desired transmissions in the coax. There is typically a high correlation between these points of ingress and points of egress in the coaxial system, since a shielding defect works equally well to permit leakage into, or leakage from, the cable system. At typical digital signal levels in the Long Term Evolution (hereinafter sometimes LTE) band, leakage levels of 1 μV/m can indicate shielding defects that could capture signals from nearby LTM devices sufficient to create interference ratios of less than 30 dB, causing potential tiling of television displays or other interruption to the subscriber&#39;s services. Although not reflecting all variables, the illustrated system includes the capacity to approximate the leakage antenna “gain” (loss) from the premises cabling using the formula: 
     
       
      
       P 
       R 
       =P 
       T 
       −L 
       L 
       +G 
       T 
       −L 
       fs 
       +G 
       R  
      
     
     where P T =power of the injected CW carriers;
     L L =loss in the coax and splitters to the point of the leak from the source;   G T =gain of the leakage antenna model;   L fs =free space attenuation from the leak to the instrument measurement antenna;   G R =gain of the instruments antenna in dBd.;   L f =generally, the antenna is connected directly to the instrument (no loss); and   P R =received power.   

     Solving for G T  yields 
     
       
      
       G 
       T 
       =P 
       R 
       −P 
       T 
       +L 
       L 
       +L 
       fs 
       −G 
       R  
      
     
     Thus, by knowing the received power (that is, the measured leakage power), the transmit power (that is, the +40 dB or +60 dB signal supplied by the carrier generator at the ground block), loss up to the location of the leak (approximated by the loss through the subscriber&#39;s interior cabling and flat loss from the ground block to the leak), free space attenuation (typically related to the distance from the leak to the rubber duck receive antenna, and calculated within the instrument), and the gain of the receive antenna (specified), the approximate gain of the leak model in dBd can readily be calculated. Once the approximate gain of the leak model has been calculated, estimate can be made of the effect of various other fields known to be present in the subscriber premises (for example, LTE fields) by applying these fields to the ingress antenna model and predicting the ratio of the desired (system carrier) to the undesired (tower or cell phone sourced signals) Problems may arise at locations where a cell tower is close (LTE downstream frequencies), or where a cellular device in the subscriber premises must transmit at high levels to reach the cell (LTE upstream frequencies). 
     Input level to the subscriber&#39;s in-premises distribution network is in the range of −5 dBmV. The cable is disconnected, for example, at the ground block, and a signal generator capable of producing at least two frequencies, for example, about 138 MHz and about 750 MHz at levels of, for example, about +40 dBmV (tire default level) and about +60 dBmV, is coupled to the subscriber&#39;s in-premises network, again, usually at the ground block. Thus, the offset for the default +40 dBmV is +45 dB. The offset for +60 dBmV is +65 dB. In the subscriber network there may be some one or more sources )f what is known as “flat” (that is, non-frequency dependent, non-distance dependent) loss, for example, (a) splitter(s), (a) tap(s) and so on. A four-way splitter might have a loss in the range of −7 dB. A tap might have a loss in the range of −3 dB. In addition, there is line loss for the length of coaxial cable between the ground block and a flaw or “leak” in the cable. This loss typically is frequency dependent and might be, for example, 6 dB/100 ft. (about 30.5 m) for about 138 MHz and 10 dB/30.5 m for about 750 MHz. Thus, the amount of loss is related to how far the leak is along the cable from the port at which the signal generator is coupled (again, typically, the ground block). Since the injected signal level amplitude is so high (+40 dBmV or +60 dBmV in the illustration), the exact numbers for the various losses are not so important as rough numbers and knowing what circuit elements) is (are) between the injection port and the leak. For example, a technician might assume one four-way splitter and no taps between the injection port and the leak. The leak “antenna” might be assumed to be a dipole radiator having a gain Gf dBd, and the measuring instrument&#39;s antenna may be a monopole having known characteristics, for example, a gain Gi dB. The technician is instructed to walk the distribution network through the subscriber premises at a distance of say 3 m from the wall. 
     According to an illustrative example, a technician disconnects the cable  106  at the subscriber&#39;s premises  100 &#39;s ground block  208 , There the cable  106  enters the premises  100  and is split in “tree and branch” topology into branches  210  running to different cable  106  outlets  212  within the premises  100  The technician then connects a dual oscillator  214 ,  216  to the ground block  208 , and two signals, one in the aircraft band and one in the LTE band, are provided to the premises  100 &#39;s internal cable  106  wiring  218 . Illustrative signals are an approximately 139.25 MHz CW signal in the aircraft band and an approximately 750 MHz CW signal in the LTE band. These signals are provided at high levels. For example, if the cable  106  signal is provided to the ground block  208  at −5 to 0 dBmV, a not-atypical level, the dual oscillator  214 ,  216  provides 60 dBmV signals at the selected frequencies to the ground block  208  (so-called power offset is about +60 dB to about +65 dB). Of course, the dual oscillator  214 ,  216  must be well shielded to prevent the dual oscillator  214 ,  216  from radiating, and the SLM  102 /antenna  104  combination from receiving, the selected frequencies radiated through the air from the oscillator  214 ,  216 . 
     The technician walks around the premises  100  with his SLM  102 /antenna  104  combination, which may be equipped with a GPS to track the technician&#39;s movements. The SLM  102 /antenna  104  combination logs signal levels as the technician moves. Peaks in the leakage signal are readily apparent on the SLM  102 &#39;s output, which may be analog (a meter or gauge) or digital (a digital display). If excessive leakage is detected, it can be traced from the log of readings and associated technician locations to (a) particular point(s) in the premises  100 &#39;s internal cable  218  wiring, fittings to output devices, etc., and directly and immediately addressed and repaired. Again, the equation governing this process is 
     
       
      
       P 
       R 
       =P 
       T 
       −L 
       L 
       +G 
       T 
       −L 
       fs 
       +G 
       R  
      
     
     where P R =received power (at the SIMM  102 /antenna  104 ) in dBmV;
     P T =transmitted power (at the dual oscillator  214 ,  216 ) in dBmV;   L L =line loss in dB in the ground block  208  and the house  100 &#39;s internal cabling  218 ;   G T =gain in dBi of the transmitting antenna (the gain of the leak in dBi);   L fs =loss in dB due to free space between the leak and the receiving SLM  102 /antenna  104 ; and,   G R =gain in dBi of the receiving antenna  104 .   P R , P T , L L , L fs  and G R  typically are known. Thus, G T  can readily be calculated.   

     Analysis of SLM  102 /antenna  104  measurement results permits, for example, the technician or a program running on a remote server  220  to which the collected data is provided to ascertain the location  222  and extent GT of the leak and generate a repair work order. 
     Analysis of the SLM  102 /antenna  104  measurement also permits, for example, a program running on a remote server  220  to which the collected data is provided to ascertain the likelihood of interference from the premises  100  entering the cable  106  system through the leak  222  and disrupting other cable  106  services. For example, if a leak  222  is large (G T  large) and the subscriber uses a cell phone  224  or like device in the premises  100 , such a program can predict with reasonable accuracy the likelihood of cell phone  224  interference with cable  106  signals provided to terminal equipment  226 , such as televisions, computers and the like, in the premises  100 . 
     Analysis of the SLM  102 /antenna  104  measurement can also provide a reasonably accurate indication of isolation. For example, if the injected signal at the ground block  208  is at +60 dBmV and a −40 dBmV signal level is read at the SLM  102 /antenna  104 , the cable  106  provider may reasonably infer that 100 dB of isolation exists between the cable  106  system and the premises  100  at the SLM  102 /antenna  104 -to-cable  218  measurement distance, for example, about 10 feet (about 3 m.). 
     The SLM  102 /antenna  104  measurement can also be used for workforce management and analysis. The measurement will be returned, for example, by DOCSIS, WiFi and/or like utilities to (a) server(s)  220  operated by the cable  106  system operator, or to whose services the cable  106  system operator subscribes. Here, the measurement(s) will be entered into the subscriber&#39;s file, along with the time(s) the measurement(s) was/were made, subscriber location/identity, information about when a work order was filled, and so on. 
     Information thus collected can also be entered into a management information base to provide alerts concerning the status of the various components of the cable  106  plant. 
     In an example, at a frequency of about 757.5 MHz, P R =40.00 dBmV; P T =+60 dBmV; L L =15 dB; L fs =39.73 dB; and, G R =2 dBi. Again, P R =P T −L L +G T −L fs +G R . Thus, G T =−47.27 dBi, If the actual reading at the SLM  102  is −40 dBmV (corresponding to 162.76926 μV/m at the SLM  102 ), and the power offset is 65 dB, the adjusted received power is (−40 −65) dBmV, or −105 dBmV corresponding to a “corrected” leakage of 0.09 μV/m. 
     On the interference side, if a cell phone  224  producing a field strength of 1.8 V/m (about 40.87 dB at the SLM  102 ) is positioned about 3 m (about 10 ft) from the leak  222  (the transmitting antenna), L fs =39.73 dB (that is, the loss between the cell phone  224  and the leak  222 , is 39.73 dB) and the leakage antenna gain, G T =−47.27 dBi, the cell phone  224  signal has a strength at the leak of about −46.14 dBmV. Since the system level is −5 dB, the interference ratio (−5 dB −(−46.14 dB)) is about 41.14 dB. 
     The SLM  102  includes a gauge, dial or display for each of the frequencies of interest, for example, about 139.2.5 MHz and about 750 MHz. All of the above calculations for each frequency are performed. by an arithmetic module in the SIM  102 . The results are output to the gauge, dial or display for each frequency.