1. Ingress Mitigation How to Defeat Ingress
March
This seminar has been developed to provide a fundamental understanding of: Defeating Ingress
Ingress, or outside signal leakage into a cable network, varies in type and intensity and may even hide in remote corners of your plant.

2. Defeating Ingress for Vital Services
Cable operators today are activating the reverse path to launch:
Video-On-Demand (VOD)
High-Speed Data (HSD)
Voice Over IP (VoIP)
Security Systems (ZigBee)
Cable operators today are activating the reverse path to launch video-on-demand (VOD), high-speed data and switched telephony services to customers. Before deploying these services, it’s critical to ensure the networks are able to handle the traffic despite concerns of noise, alignment and ingress.

3. Methods for Defeating Ingress
Proactive solutions for defeating ingress problems exist. Accurately Monitors Leakage in All Digital Systems or Mixed Digital and Analog Systems
Perform lockdown procedures
Suppressing ingress
24 hour monitoring
Sweeping and certifying the network
Testing bit error rates
Several tests and techniques are used to identify the presence of reverse path interference, isolating the source of ingress and maintaining the plant to correct problems and minimize future ones. No single solution provides a full answer—operators need a combination to achieve a tight plant and robust return path that allows customers to fully enjoy the two-way services being delivered.
Six proactive measures for conquering ingress problems exist.

4. Methods for Defeating Ingress
Perform Lockdown Procedures
Method 1: Perform lockdown procedures
Experts estimate that 80 percent or more of all ingress and egress (signal leakage out of a system) issues are in the drop system. Of those, the majority are connector-related. Most networks today are built out and should be "tight." But technicians haven’t always known the problems loose connectors can cause. Also, the drop system where the majority of coax cable and connectors reside is typically not as well-maintained and well-shielded as the trunk and feeder portions of the network.
80+%

5. Methods for Defeating Ingress
Perform Lockdown Procedures
Visit every Drop
Tighten Housings
Tighten F-Connectors
Reseal Ground Block
Audit Taps
Terminate Ports
Verify Drop Integrity
Lockdown is a basic, but extremely effective method of getting a high-integrity plant. It involves visiting every connection point in the network, tearing down the heat shrink if required, tightening housing connectors and F-connectors for drops at every tap and ground block resealing. A single technician may perform lockdown without interacting with the headend, and no special test equipment is required.

6. Methods for Defeating Ingress
Perform Lockdown Procedures
Lockdown is a simple tightening up of the plant/drop system.
This must be a collective effort from all technicians at all levels.
The integrity of the plant is up to ALL of us to ensure MAXIMUM customer satisfaction.
Conclusion: Lockdown is a simple tightening up of the plant—it doesn’t tell you what is happening between the poles, but it can address a significant portion of ingress problems if implemented uniformly across the plant. Perhaps the biggest drawback to lockdown is that it does not provide a positive elimination of ingress because no real determination of cause exists.

7. Methods for Defeating Ingress
Suppress Ingress
Suppression measures may be used with lockdown procedures or alone to isolate and correct sources of ingress. It may be performed instead of lockdown if the plant is already in satisfactory condition, or to ensure the new plant was constructed correctly.

8. Methods for Defeating Ingress
Suppress Ingress
Technique 1: Trial and Error
A 9581 SST at the hub or headend
Coordinate with the field to isolate the point of ingress
At each leg, a technician pulls pads and disconnects the return path from each splitter point
OR they use a probe such as the I-Stop
If there’s no impact on the ingress, they move on
Headend
Ingress suppression involves putting a spectrum analyzer at the hub or headend, monitoring the noise floor or checking for unwanted carriers, and then coordinating with field teams to isolate the point of ingress. The procedure is somewhat of a trial-and-error method. Teams might start in a larger area such as a node, then break it down into sections of the feeder plant. At each leg, a technician pulls pads and disconnects the return path from each splitter point, while another technician monitors the impact at the headend. If there’s no impact on the ingress, they move on to the next section until they find the problem area.

9. Methods for Defeating Ingress
Suppress Ingress
Technique 2: Headend Monitoring & Field Compare
Headend
Ingress suppression involves putting a spectrum analyzer at the hub or headend, monitoring the noise floor or checking for unwanted carriers, and then coordinating with field teams to isolate the point of ingress. The procedure is somewhat of a trial-and-error method. Teams might start in a larger area such as a node, then break it down into sections of the feeder plant. At each leg, a technician pulls pads and disconnects the return path from each splitter point, while another technician monitors the impact at the headend. If there’s no impact on the ingress, they move on to the next section until they find the problem area.

10. Methods for Defeating Ingress
Suppress Ingress
Leakage Detection
Suppressing ingress via leakage detection is critical
Ingress vs FM vs LTE
Pressurization of the home/mdu can show the most minor of ingress points that can cause major upstream issues, along with LTE problems

11. Methods for Defeating Ingress
Suppress Ingress
High-Speed Spectrum Analyzer
Allows you to find and track ingress
Traffic Control Plus
Allows you to see ingress directly underneath the upstream carriers
Upstream Linear Distortions
Allows the technician to find micro-reflections / impedance mismatches
FDR
Allows the user to locate opens/shorts via a Frequency pulse

12. Methods for Defeating Ingress
24 Hour Ingress Monitoring

13. Methods for Defeating Ingress
24 Hour Ingress Monitoring
Addition of VoIP service requires a higher level of integrity
Constant monitoring means an automated system is essential
SNMP trap management with controllable limits, alarms and selective notification is commonly used to create work orders and jobs for maintenance techs
Alarm Notification is critical for upstream maintenance
That word “hygiene” makes me think of dental hygiene – something we were taught in early childhood. Good dental hygiene requires consistent maintenance. An automated system enables 24/7 monitoring, and trap management ensures notification only when the situation warrants it.

14. Methods for Defeating Ingress
24 Hour Ingress Monitoring
Monitoring Operation
Most monitoring systems use frequency scanning for return band analysis
limits set to detect ingress and noise problems
When limit is crossed, “trap” or alarm is triggered
Limits are configurable, and alarm is scalable, to gauge response urgency
Most of the monitoring systems on the market use a frequency scanning analysis of the return band, with limits set to detect ingress and noise problems. When the alarm limits are crossed, a “trap” or alarm is triggered. The limits are configurable, and the alarm is scalable, to gauge the response urgency.

15. Methods for Defeating Ingress
24 Hour Ingress Monitoring
The Value of Monitoring
Useful before and after initiating service
Used to prepare the node for certification
Then to actually certify the node
Then to maintain the node and as an aid to locate problems before they impact the subscriber
Goal: >40dB “carrier-to-crud” ratio
Most of the monitoring systems on the market use a frequency scanning analysis of the return band, with limits set to detect ingress and noise problems. When the alarm limits are crossed, a “trap” or alarm is triggered. The limits are configurable, and the alarm is scalable, to gauge the response urgency.

16. Methods for Defeating Ingress
24 Hour Ingress Monitoring
Catching the Transients
Impulse noise, and intermittent ingress can be difficult to catch with conventional analysis schemes
Looking at one node when ingress occurs at another
Looking at one frequency, when ingress occurs at another
Not all return band monitoring systems are the same. Those using conventional analyzer technology can miss significant amounts of impulse noise that, can have a serious impact on services.

17. Methods for Defeating Ingress
24 Hour Ingress Monitoring
Selecting a Monitoring Solution
Seeing all forms of ingress is primary concern
relatively stable forms of CPD and ingress
very transient ingress and impulse noise
Monitoring analyzer must be very fast (DSP)
Must be able to discern interfering signals within band of legitimate system carriers (Traffic Control)
In selecting a monitoring system to implement, a primary concern should be to be able to see all forms of ingress, including not only relatively stable forms of CPD and ingress, but very transient ingress and impulse noise. The monitoring analyzer must be very fast, and it must be able to discern interfering signals from legitimate system carriers. There is a significant advantage to using DSP technology in analysis.

18. Methods for Defeating Ingress
24 Hour Ingress Monitoring
The DSP Advantage
Catches transients that other methods miss
120 Spectrum “snapshots” a second
“Sees” entire spectrum at once, digitizes it, and converts it to the frequency domain using fast Fourier transform.
There is not a faster method for capturing ingress.
Digital signal processing provides a much more effective acquisition of return spectrum, and is quick enough to capture impulse transients that impair communication services.

19. Methods for Defeating Ingress
24 Hour Ingress Monitoring
DSP Examples
The “snapshot” is captured in the time domain, and converted to the frequency domain using fast Fourier transform.
Time Domain
Frequency Domain

20. Methods for Defeating Ingress
Return Sweep
As is true with the forward path, sweeping the reverse path is regarded as the best approach to balancing and aligning in accordance with the manufacturer’s equipment specifications. Sweeping also points out physical defects, component failures, quality of splices and overall plant craftsmanship.

21. Methods for Defeating Ingress
Return Sweep
One person operates a sweep generator that injects a return sweep signal
A receiver in the headend monitors the injected return sweep
The headend unit digitizes the frequency response "seen" in the headend, then sends it down stream
The technician’s field unit then displays the return frequency response as it appears in the headend
Sweeping the network may be done with one person operating a sweep generator that injects a return sweep signal. A receiver in the headend monitors the injected return sweep. The headend unit digitizes the frequency response "seen" in the headend, then sends it down stream via a narrow bandwidth telemetry carrier. The technician’s field unit then displays the return frequency response as it appears in the headend, making return sweep alignment a one-person job. The sweep technician checks input levels for conformity to system design, monitors sweep alignment to ensure amplifier frequency response meets system parameters, and adjusts amplifier pad and equalizers to design specifications or to compensate for any plant changes.

22. Methods for Defeating Ingress
Return Sweep
Sweeping the network may be done with one person operating a sweep generator that injects a return sweep signal. A receiver in the headend monitors the injected return sweep. The headend unit digitizes the frequency response "seen" in the headend, then sends it down stream via a narrow bandwidth telemetry carrier. The technician’s field unit then displays the return frequency response as it appears in the headend, making return sweep alignment a one-person job. The sweep technician checks input levels for conformity to system design, monitors sweep alignment to ensure amplifier frequency response meets system parameters, and adjusts amplifier pad and equalizers to design specifications or to compensate for any plant changes.

23. Methods for Defeating Ingress
Return Sweep
Hand held tester
Verifies return path loss
Generates return path test signal
Ranges to determine appropriate launch level
Compares with limit for pass / fail result
Tests return band noise/ingress
Finds bad cable
Terminators
Impedance mismatches
Improperly setup amps
Bad Transmitters
Bad passives and actives
Sweeping the network may be done with one person operating a sweep generator that injects a return sweep signal. A receiver in the headend monitors the injected return sweep. The headend unit digitizes the frequency response "seen" in the headend, then sends it down stream via a narrow bandwidth telemetry carrier. The technician’s field unit then displays the return frequency response as it appears in the headend, making return sweep alignment a one-person job. The sweep technician checks input levels for conformity to system design, monitors sweep alignment to ensure amplifier frequency response meets system parameters, and adjusts amplifier pad and equalizers to design specifications or to compensate for any plant changes.

24. Methods for Defeating Ingress
Testing MER & BER
Testing MER gives us the ability to see SNR / C/N on a digital channel
Testing BER allows us to know how well the bit stream is performing at the specified location
It’s critical that the technician conduct bit error rate (BER) tests prior to offering digital voice or high-speed data on a hybrid fiber/coax (HFC) network, as well as perform on-going tests after these services are offered.

25. Methods for Defeating Ingress
Testing Bit Error Rate
Coherent Interference
Phase Noise
BER—the ratio of errored bits to the total number of bits sent in a given time period—gives an overall measure of the quality of a received bit stream. BER is the highest integrity, most robust test for digital services because it closely mirrors digital traffic.

26. Defeating Ingress Summary
Maintaining the entire spectrum is mission critical
Stopping ingress in it’s tracks can provide an extremely high QOS for end users
Helps reduce repeat trouble calls, therefore keeping customers happy
Ingress and poor customer service are the leading reasons for not retaining your customer base
It is the job of all employees to make sure the system is locked down and tight, therefore minimizing potential ingress in both the upstream and downstream
Having the right test equipment that has the abilities to trouble shoot these critical aspects of the network can lead to reduced troubleshooting times, allowing the network to go online quicker, therefore making happier customers!

27. Questions?