Why is it important to repair all noise ingress points in our HFC network?
Ingress has been one of the greatest challenges faced by cable operators, only worsened by the introduction of bidirectional services and now by new demands from LTE operators. These ingressions are typically described as:
CLI – Cumulative Leakage Index (Radiating Dome Effect or Funnel Effect): numerous small sources of ingress are additive, as many branches of the typical tree-and-branch structure combine to form a common trunk, creating a much larger end effect. A single weak point in shielding can disable services for an entire node if located near a noise source.
Noise is often intermittent – there is nothing more frustrating than tracking an ingress problem for hours only to have it disappear. Each time the noise source is reactivated, a desperate race begins to locate where it enters the plant before it vanishes again.
Cleaning any type of noise is one of the most difficult practices for technicians during HFC network maintenance. Over the years, technicians have gained considerable experience applying segmentation techniques to detect and repair these ingress sources, but these common field practices generate customer dissatisfaction, potentially leading to service cancellations.
What types of problems can our noise search system solve?
- Mitigate ingress/egress problems
- Locate physical problems in the plant
- Picture lines
- Picture ghosting
- Pay-per-view problems
- High-speed data problems
- Interference with bidirectional radio services using the same frequencies
- Picture mosaic
- Frozen frame
- Picture and sound blackout
- Destructive to plant physical condition
- Cellular interference
- Improved system performance
- Prevent over-the-air transmission interference
All of these problems are very difficult for cable operators to predict, and they cannot control external noise sources affecting their services. However, they can control the weak shielding points that allow noise to enter. This is where our proposal for network-wide ingress search and detection can evaluate your quality by detecting leaks outside the plant through a methodical pattern and GPS to locate leak points on a map.
Our equipment will help you maximize HFC plant quality and problem resolution time by proactively discovering any network issues. When a leak is fixed, a potential ingress point is also eliminated. The coaxial network will not interfere with LTE services and LTE services will not interfere with network communication, enabling full gigabit service potential. A tuned network will be ready for future technologies and services, and customers will be happier when technician work is completed faster and more effectively (without service calls).
Key benefits for pressure testing
- Ensure that shields/devices are appropriate and the system is tuned
- Close the system to LTE interference, with no LTE leaks
- Help enable full gigabit speeds (US/DS metrics)
- Prepare home/MDU for future technologies
- Keep customers happier by not only reducing work time but improving service quality
A signal leak in a cable is invisible, making it impossible to locate the source without some kind of instrument. Here is where our noise search system and centralized data post-processing will help you determine each of these properly located points, giving you the latitude and longitude coordinates of the leak source. Additionally, our instruments are prepared for both high-frequency and low-frequency leaks, as most leaks only manifest at one end of the spectrum or the other. Taking this limitation into account, a signal leak at one point can mask a leak at another nearby point. Signal leaks can also be intermittent, meaning that if a leak occurs due to a slight crease or movement in the cable, it may not be detected until it occurs again.
You can also be assured that we will only detect leaks that are on your network and not other noise sources in the environment or on other networks in the same area, as our noise search equipment is prepared for this discrimination. It does so by injecting a “tag” – a unique radio frequency signal into the cable plant – which field monitoring instruments can then detect.
How We Will Conduct Noise Search in Your Network
The first thing we must determine is at what frequencies to place the equipment transmitting from the headend called CT4 or CTX. Generally, when using a standard SCTE channel alignment, it is recommended that carriers be injected into the system at 138 MHz and 612 MHz, which is the guard band between QAM or analog carriers depending on the type of channel residing at each frequency. Similarly, the CTX equipment has the agility to transmit up to 4 frequencies from 130 to 1220 MHz:
The carriers are injected at 30 dB (LTE) and 36 dB (aviation) below the adjacent carrier to eliminate the risk of affecting those channels/digital services.
The CT4/CTX tagger is installed at the headend and occupies only one Rack unit; this provides a failsafe solution for active analog and digital systems. The CT4/CTX can insert VIAVI’s proprietary tagged signals in both the aviation range and the near LTE range simultaneously, ensuring that you are only tracking leaks in your system.
- CT4/CTX Output – This is the RF output connection that must be summed to your channel alignment.
- AC Power Input: Accepts AC input power of 90 to 370 VAC (47-440 Hz), 0.75 A.
Additionally, an audible tone will sound if the measured signal breaks the muting threshold, which will also help locate the potential source of the leak.
SeekerD/SeekerX (Field/Vehicle) – MCA III
- Captures aviation and LTE leaks simultaneously
- Highest sensitivity equipment to find the smallest leaks from bad/loose connectors and cables
- Proprietary algorithms quadrangulate leak data to a precise location for dynamic/direct dispatch
- Comes with specially designed antennas to find leaks quickly
- MCA III offers high-performance documentation features and GPS location recording
- MCA III automatically monitors leak bursts and records data with time and date stamp, and GPS location of the leak
- Data log uploads to a server can be fully automated
After completing the survey, all data can be loaded into our post-processing system called LAW (Leakage Analysis Workshop™). We will send you a detailed report with properly located leak points, indicating the latitude/longitude coordinates and intensity level, and we can also include in the report the entire survey route on the map and the leak points detected in the network.
Example Report with leak data:
| Work Order | Location | Level μV/m | Latitude | Longitude | Date |
| 17202 | Calle XXX - José XXX, XXX, Buenos Aires | 2000 | -34,XXXXX | -59, XXXXX | 06/01/2019 |
| 17042 | Bella Vista, Buenos Aires XXXX | 1799 | -34,XXXXX | -58, XXXXX | 05/31/2019 |
| 17379 | Ramón Gómez, XXXXX, Buenos Aires | 1795,8 | -35,XXXXX | -57,XXXXX | 05/31/2021 |
| 17203 | Calle XXXX - H. XXXX, XXXX, Buenos Aires | 1794 | -34,XXXXX | -59,XXXXX | 06/01/2019 |
| 17425 | Blandengues XXXXX, XXXXX, Buenos Aires | 1754,8 | -35,XXXXX | -57,XXXXX | 05/31/2021 |
| 17204 | Calle XXXX - Leopoldo XXXX, Buenos Aires | 1660 | -34,XXXXX | -59,XXXXX | 06/01/2019 |
See which areas have been surveyed and which areas still need to be explored
Problems found
We would be happy to send you a quote for this service. Just let us know the number of nodes you would like us to survey and their location.