Texas Gulf Coast Chapter of SCTE presents… “Cumulative Leakage Index” What? Why? Who? Where? When? And How?
Listen for answers to these questions… • What is CLI? • Why do I need to be concerned with CLI? • FCC ---who are they and why are they involved? • Why keep leakage logs? • What’s a microvolt? • What is noise and how can it impact customers? • Is there a direct correlation between CLI and other distortions? • Why is the customer's home a major contributor to system problems? • Why is proper cable and connector craftsmanship so important?
What is Leakage? *Cumulative Leakage Index (CLI) CLI is the net effect of the combination of all the leaks in the system added together =the amount of radio frequency (RF) signal that escapes or infects the cable system These cumulative leaks form an invisible cloud of unwanted RF energy over the cable system • Leakage results from: • Improper cable installation • component corrosion • poor product design • Vandalism • cable breaks • poor connections
Two types of leakage: Egress and Ingress • Egress= RF signal leaking out of the cable system • Damaged cable • Improperly installed cable • Signal escapes and follows the path of least resistance including free space (air), strand, power and phone lines • Ingress= RF noise or interference that leaks into the cable system through a break or external leak (loose connectors) • Hair dryers, microwaves, radios, etc. • Feeds into the coax drop from bad TV’s, long center conductors, amplifiers, jumpers, customer equipment (VCR)
Ingress/Egress Ingress: RF signal leaking into the coaxial plant Egress: RF signal leaking out of the coaxial plant
Why Is It Important to Determine Leakage? • Cable television systems and licensed over-the-air broadcasters use many of the same frequencies to transmit programming. Specifically, cable systems use TV, radio and aeronautical radio channels, among others, within their cable plant. • Cable operators are considered the secondary users of these frequencies; therefore they must not interfere with the licensed over-the-air users who are the protected (primary) users of these frequencies.
What Problems Can Signal Leakage Cause? • Cable signal leakage can interfere with any of the over-the-air services that happen to be using the same frequencies as the cable operator and that are within the vicinity of the cable system. • Such interference, especially on the emergency channels, can interfere with the communications of safety personnel or airplane pilots. • When such interference occurs, it can endanger the lives or hamper the rescue efforts of safety personnel.
What are the FCC Rules Governing Signal Leakage? • The FCC (Federal Communication Commission)has set maximum individual signal leakage levels for cable systems. • The FCC sets even more stringent limits for cable systems that may interfere with aeronautical and navigation communications. • As a further measure, the FCC requires cable operators to have a periodic, on-going program to inspect, locate and repair leaks on their systems. –FCC files include: • CLI quarterly ride outs (100% of system & log all leaks) • Annual Flyovers (report on form 320) • Daily Leakage Logs (date found/date repaired)
Can the Cable Company be penalized if it fails to control CLI? 4/17/2012 Pays to keep the system clean… In this Notice of Apparent Liability for Forfeiture (NAL), we find that Cebridge Acquisition, LP (Cebridge), operator of the cable television system in Honey Grove, Texas, apparently willfully violated Sections 76.605(a)(12) and 76.611(a)(1) of the Commission’s rules (Rules), by failing to prevent excessive signal leakage in the Honey Grove cable system. We conclude that Cebridge is apparently liable for a forfeiture in the amount of eight thousand dollars ($8,000).
Quarterly CLI Drive Out Results Unauthorized Connection 1333 44.7% Loose F Connector 426 14.3% Loose Terminator 185 6.2% Replace Connector 142 4.8% No Fault Found 415 13.9%
Who’s Responsible? AndWhat can I do? It is a shared responsibility across Operations and Engineering.
Five Steps in Leakage Abatement • Detection • Location • Measurement • Correction • Re-measurement
Detection (What do I need?) • Carrier Generator- a unique frequency inserted by the headend that can be recognized by the leakage detector tuned to the carrier’s frequency • Leakage Detector- (Seekers’, Searchers’, Sleuths’)-provided and used by all technicians to detect leaks in the free space where RF energy is encountered
Calibrating Leakage Equipment 1.Connect calibrated signal source set at 20 uV/m. 2. Position the dipole antenna. 3. Adjust to read 20 uV/m.
Hand Held Detectors • Check the battery voltage, insure the unit is charged before you proceed to isolate the leak • Listen to the audible alarm indicator as you proceed to isolate the leak source • Increases in the tone pitch indicate you are closer to the source • Decreases in the tone pitch indicate you are moving away from the leak source • Follow the manufacturers recommended mode to identify the leak source • Once the leak is identified to a pole, cable, or a home, follow standard troubleshooting procedures until the leak is within compliance
Measurement-rules of engagement • Once a leak is located it must be measured • μV/M What is a microvolt per Meter? • Standard unit of measure for CLI • 50 Ohm off air measurement • Voltage developed in 1 meter of infinitely thin section of wire submerged in a leakage field produces 1μV of energy • All leaks greater than 20 microvolt's MUST be repaired per FCC rules • Any leak greater than 50 microvolt's MUST be repaired IMMEDIATELY per FCC rules
Measurement-rules of engagement (cont.) • Only leaks above 50 μV/m are used in CLI calculation • All measurements taken outside 108-137 MHz must be converted as if they were taken within the band • Leakage Detector-measures the level of the leak • Take the reading at about 10 feet (3 meters) • Repair it • Re-measure
Measurement-rules of engagement (cont.) • Use a calibrated halfwave dipole antenna • Antenna must be elevated 3 meters off the ground and positioned 3 meters from the leakage source • Antenna must be rotated 360º in the horizontal plane for maximum reading
Let’s Practice finding a leak Turn on your Leakage Detector!
Measurement-Why do we care? 1. Meet FCC Compliance 2. Prevent Off-Air Interference • Aeronautical & Aircraft Communications • Amateur Communications • Broadcast TV signals (Analog & Digital) • Public and Emergency Communications • Radio Mobile Communications
Measurement-Why do we care? 3. Improves System Performance • Reduces Repeat Service Calls • Locate Physical problems
Correction of Leak 80% of all leakage is caused by problems from the tap to customer equipment Common Causes of Leakage- • Loose drop connectors • Improperly installed connectors • Inferior quality coaxial cable, passives, or connectors • Poorly-shielded drop cables • Bad connectors at the taps • Bad/loose port terminators • Corroded connectors
Correction Common Causes of Leakage-cont. • Cracks in the trunk and feeder cables • Animal chews • Physical trauma to cables or connectors • Aging and environmental stress • Loose hard line connectors
Correction Common Causes of Leakage-cont. • Customer installed equipment • Damaged amplifier housings • Loose amplifier housing lids • Broken tap ports • Poor installation of splices and connectors • Poorly-shielded customer premise equipment
Ingress impacts on Digital Channels • Macro Blocking (Tiling) • Freeze Frame • Picture and Sound go to black • Robotic Voice • Data Packet Loss or slower speeds • Repeat Service Calls
Ingress impacts on Analog Channels • Lines in picture • Ghosting • Pay-per-view problems • Interference with two-way radio services using the same frequencies • Repeat Service Calls
Correction • Repair the leak- determine the root cause and use TWC procedures to implement proper restoration • Tighten or replace connectors • Replace cracked or damaged cable • Terminate open ports with 75 ohm terminators • Correct customer created issues (replace splitters, self-run inferior cable) • Properly terminate unauthorized connections and report theft of service to Audit/Security operations
Audit/Security Process • Insert your local process and contact information
Re-measurement • Take a final reading using the same equipment and record the corrected CLI calculation (reportable to the FCC) • If the leak is still above 20 microvolt's it is NOT repaired (incomplete diagnosis-reengage) • Work the issue backtracking all the cable and connections • Correct issue until leak is under 20 microvolt's
CLI tips • Turn on your CLI equipment and use properly • Record/Repair/Re-measure your leaks • Tighten all connectors • Use PPC Signal Tight Connectors indoors • Properly terminate open ports • Disconnect unauthorized drops and properly terminate
Benefits of CLI program • Reduced ingress/noise in the plant (SNR) • Increased plant performance (FEC) • Better CPE performance thus improved Whole House Check • Reduction in Trouble Calls (TC to RGU and rework) • Customer Satisfaction!
Customer FAQ’s Be careful using the word “radiate.” (Q & A’s from the FCC website)
FAQ’s from the customer • Does a Cable Operator Need to Come into My Home to Monitor for Signal Leakage? • Usually, no. Cable operators can use equipment to locate the general area of a leak. To pinpoint a leakage source for subsequent repair, however, the cable operator may request access to your home. • Am I Required to Let the Cable Operator into My Home to Monitor for and Repair Signal Leakage? • Homeowners have the right to deny access to their premises. If a leak cannot be repaired without access to your home, however, a cable operator can disconnect your service for denied access.
FAQ’s from the customer (cont.) • Can My Cable Operator Terminate My Service Because of Signal Leakage? • The FCC’s rules allow cable operators to disconnect service in order to repair signal leakage that exceeds FCC standards. The operator restores service when the signal leakage problem is remedied, and may not charge you for service while it is disconnected. • Is the Cable Operator Responsible for Repairing Signal Leakage on Subscriber-owned Equipment? • No.
FAQ’s from the customer (cont.) • Can I Hook Up a Second Set Myself? • In terms of the signal leakage rules, yes, but because the cable operator is responsible for leakage from the wiring, the operator can either refuse to connect to it or terminate service if the hook up causes signal leakage problems. • Is Signal Leakage Biologically Harmful? • The power levels used in a cable system are low. Therefore, it is unlikely that cable signal leakage from a cable facility will exceed the FCC’s RF allowable limits for RF exposure.
Thanks for your Participation Join the SCTE Texas Gulf Coast Chapter TODAY!!!