Introduction: Cable Signal Leakage. Cable signal leakage, sometimes called egress, occurs when RF signals “leak out” from the cable plant and spread into the environment. Cable. signal leaks can be caused by loose connectors, damaged plant cables. or cracked or unterminated cables. And egress or leakage is an open
What is cable signal leakage?
Cable Signal Leakage Cable signal leakage, sometimes called egress, occurs when RF signals “leak out” from the cable plant and spread into the environment. Cable signal leaks can be caused by loose connectors, damaged plant cables or cracked or unterminated cables.
How did the cables leak start?
The United States diplomatic cables leak, widely known as Cablegate, began on Sunday, 28 November 2010 when WikiLeaks began releasing classified cables that had been sent to the U.S. State Department by 274 of its consulates, embassies, and diplomatic missions around the world.
What is leakage current in electrical installation?
In any electrical installation, some current will flow through the protective ground conductor to ground. This is usually called leakage current. Leakage current most commonly flows in the insulation surrounding conductors and in the filters protecting electronic equipment around the home or office.
What is the value of leakage from telecommunications equipment?
When telecommunications equipment is present, the value of leakage indicated by a clamp meter may be considerably more than that resulting from insulation impedance at 60 Hz. This is because telecommunications equipment typically incorporates filters that produce functional grounding currents and other equipment that produces harmonics, etc.
What is cable signal leakage?
Signal leakage refers to the loss or egress of radio frequency (RF) signals from a cable system when they are not properly contained. This can result from a multitude of causes but is generally the result of shielding defects within the cable network.
How do you test for signal leakage?
1:533:04Signal Leakage and Noise Ingress Detection Demo - YouTubeYouTubeStart of suggested clipEnd of suggested clipAnd contracts several leaks at once at night the captured leakage data can be uploaded automaticallyMoreAnd contracts several leaks at once at night the captured leakage data can be uploaded automatically using Wi-Fi the leakage data can then be used by a technician to locate large leaks for diagnosis.
What is the maximum allowable amount of signal leakage at 3 meters away from the cable plant?
20 microvolts per meterNearly all cable operators monitor for signal leakage in or near the 108 MHz-137 MHz aeronautical band, within which the maximum allowable leakage field strength is 20 microvolts per meter (µV/m) at a distance of 3 meters (~10 feet) from the plant.
How often must a cable operator monitor for signal leakage according to the FCC?
A: You must perform CLI testing once a year and at an interval of no more than 12 months (i.e. the next CLI test must always be completed within 12 months of the completion date of the previous years test).
What is leakage in signal processing?
Leakage is the smearing of energy from the true frequency of the signal into adjacent frequencies. Leakage also causes the amplitude representation of the signal to be less than the true amplitude of the signal.
What can cause interference in a cable?
There are three components to any interference problem: (1) a source of radio-frequency energy or electrical noise, (2) a piece of susceptible equipment and (3) a path over which the unwanted energy is propagated.
How is RF leakage measured?
The measurement of signal leakage is fairly straightforward: Using a dedicated leakage detector (typically with a built-in antenna), orient the detector and its antenna to get a maximum reading and see what value the leakage detector reports.
How does leak detection cable work?
The water detection cable is activated by liquid* bridging the adjustable sensors. The cable can detect water film from zero height (water sensors turned out to make contact with the floor) to 1/8″ height (sensors turned all the way in).
What does CLI stand for in cable?
The Advisory Committee on Cable Signal Leakage developed the Cumulative Leakage Index (CLI) in an attempt to provide a simple, positive means to assure that cable television systems do not interfere with aircraft navigation or communications systems.
What causes cable TV tiling?
TV pixelating, snowing, tiling, or ghosting are all forms of display picture degradation often caused by a weak signal. Sometimes, pixelating will have nothing to do with your TV unit or cables at your home. At times, the problem is at the source.
Why does spectral leakage occur?
1) The mismatch between the tone of the signal and the chosen frequency resolution (result of sampling frequency and the FFT length) leads to spectral leakage (experiment 1).
What does ingress mean in cable?
Ingress, as far as the CATV community is concerned, is the entrance into a cable system of any undesired external radio source. Ingress will occasionally be in the form of static or electrical noise, but it is normally considered to be interfer- ence from a radio frequency signal.
What causes a signal leak in a coaxial cable?
Cablesignal leaks can be caused by loose connectors, damaged plant cablesor cracked or unterminated cables . And egress or leakage is an openinvitation for ingress, when outside signals get into a coaxial cable causinga disruption in online and voice services, poor picture quality, tiling, andpicture freezing. These lead to customer complaints and result in longhours of troubleshooting. But signal leakage also has other repercussionsfor the operator, the most serious being the increased liability due to“harmful” interference with aeronautical communication.
When did the cable industry start to be disturbed?
In 1971 the Federal Aviation Administration (FAA) was becoming increasingly disturbed about cable’s use of the aeronautical frequencies and took their concerns to the Federal Communications Commission (FCC).
What is the FCC requirement for cable operators?
The FCC requires cable operators to have a periodic, on-going program to inspect, locate and repair leaks on their systems. The cable operator is responsible for ensuring that any devices attached to the cable system meet the requirements of the FCC rules and that no “harmful” interference is caused by the cable system. And it’s not just the equipment in your outside plant; this also applies to the equipment in customer homes, including those devices not provided by you, the operator. A cable operator must take immediate measures to correct a leakage problem on their system, no matter where the leak is coming from. Sometimes this involves shutting off the offending devices (and your customer) until repairs are made and no leakage exists.
Does fiber optic cable have RF interference?
With fiber there are no radio frequencies being used, and therefore no RF interference. Specifically, the thin strands of glass composing fiber effectively replace RF transmissions with pulses of light and color, meaning the technology produces no signal leakage at all.
What is leakage meter?
Leakage meters that can detect potential egress/ingress points even when the ambient source is not present are vital to maintaining a high-quality user experience. Going back to the fluid leakage analogy, a common technique used to test for existing or potential fluid leaks is the use of hydraulic pressure to detect or verify resistance to leakage. The increased pressure enables detection of minor weaknesses that would be undetectable at standard pressures.
How often does the FCC assess cable leakage?
In addition, the cumulative leakage index (CLI) must be assessed once per year.
What is RF leakage?
What is RF leakage? Signal leakage refers to the loss or egress of radio frequency (RF) signals from a cable system when they are not properly contained . This can result from a multitude of causes but is generally the result of shielding defects within the cable network. In the US, FCC standards for signal leakage encompass egress from both analog and digital cable systems. Signal leakage has taken on renewed importance recently as issues like LTE interference have piqued government and mobile operator attention globally.
Can metal interfere with signal leakage?
Metal objects can also interfere with signal leakage detection equipment . Since this equipment was originally conceived to accommodate the aeronautical VHF frequencies, long standing practices and equipment are not always effective in detecting leakage at higher frequencies or measuring noise-like QAM signals.
Can cable networks be sealed?
The reality is that cable networks are not perfectly sealed, and as a result signals from cable networks can escape (egress) and interfere with off-air signals at the same frequencies. Conversely, off-air signals can enter into the cable network (ingress) and interfere with the cable signals. The FCC limits imposed on signal leakage originated ...
Is cable signal leakage visible?
However, unlike fluid leakage, cable signal leakage is invisible, and therefore more difficult to pinpoint the source of the leak. Given this constraint, a signal leak from one location can potentially mask a leak from a nearby location. Signal leaks can also be intermittent, meaning a slight bend or movement in the cable from one point in time ...
Where does leakage current flow?
This is usually called leakage current. Leakage current most commonly flows in the insulation surrounding conductors and in the filters protecting electronic equipment around the home or office.
What is leakage current clamp meter?
One way of going about this is to use a leakage current clamp meter. These are very much like the clamp meters used for measuring load currents, but deliver significantly better performance when measuring currents below 5 mA. Most clamp meters simply won't register such low currents.
Why does insulation leak?
The causes of leakage current. Insulation has both electrical resistance and capacitance - and it conducts current through both paths. Given the high resistance of insulation, very little current should actually leak. But -- if the insulation is old or damaged, the resistance is lower and substantial current may flow.
What is clamping phase?
Clamping phase/neutral/ground together identifies imbalance current that represents leakage at an outlet or electrical panel via unintentional paths to ground (such as the panel sitting on a concrete base). If other electrical bonding connections exist (such as a connection to a water pipe), a similar imbalance may result.
Can a clamp meter read low current?
Most clamp meters simply won't register such low currents. Once you place the jaws of a clamp meter around a conductor, the value of current it reads depends on the strength of the alternating electromagnetic field surrounding the conductors.
Can a clamp meter detect a single core cable?
Avoid twisting the jaws of the clamp meter as this can cause erroneous measurements. The clamp meter detects the magnetic field surrounding conductors such as a single core cable, a wire armor cable, a water pipe, etc.; or the paired phase and neutral conductors of a single-phase circuit; or all live conductors (3-wire or 4-wire) ...
When did the Cablegate leak start?
The United States diplomatic cables leak, widely known as Cablegate, began on Sunday, 28 November 2010 when WikiLeaks began releasing classified cables that had been sent to the U.S. State Department by 274 of its consulates, embassies, and diplomatic missions around the world. Dated between December 1966 and February 2010, ...
When was the first WikiLeaks cable released?
The first document, the so-called Reykjavik 13 cable, was released by WikiLeaks on 18 February 2010, and was followed by the release of State Department profiles of Icelandic politicians a month later. Later that year, Julian Assange, WikiLeaks' editor-in-chief, reached an agreement with media partners in Europe and the United States to publish the rest of the cables in redacted form, removing the names of sources and others in vulnerable positions. On 28 November, the first 220 cables were published under this agreement by El País ( Spain ), Der Spiegel ( Germany ), Le Monde ( France ), The Guardian ( United Kingdom) and The New York Times ( United States ). WikiLeaks had planned to release the rest over several months, and as of 11 January 2011, 2,017 had been published.
How many cables are classified as confidential?
Over 130,000 of the cables are unclassified, some 100,000 are labeled "confidential", around 15,000 have the higher classification "secret", and none are classified as "top secret" on the classification scale.
When did WikiLeaks publish the cables?
In response, WikiLeaks decided on 1 September 2011 to publish all 251,287 unedited documents. The publication of the cables was the third in a series of U.S. classified document "mega-leaks" distributed by WikiLeaks in 2010, following the Afghan War documents leak in July, and the Iraq War documents leak in October.
When did WikiLeaks get removed?
Amazon.com removed WikiLeaks from its servers on 1 December 2010 at 19:30 GMT, and the latter website was unreachable until 20:17 GMT when the site had defaulted to its Swedish servers, hosted by Bahnhof .
When did the Guardian release the cables?
The Guardian released its coverage of the leaked cables in numerous articles, including an interactive database, starting on 28 November. Der Spiegel also released its preliminary report, with extended coverage promised for the next day. Its cover for 29 November was also leaked with the initial report.
Did NOS get Wikileaks cables?
NOS announced on the same day that it had obtained these same cables from Wikileaks. Die Welt, a German daily newspaper, announced on 17 January 2011 that they had gained access to the full set of cables, via Aftenposten. Australian-based Fairfax Media obtained access to the cables under a separate arrangement.
A Leakage Overview
Leakage is any electrical energy transfer that goes over the accepted limits. The transfer always exists, and we assess it as insulation. Here are the common leakage examples!
Leakage Current Measurement
On circuits protected by GFCIs (Ground Fault Current Interrupters), leakage current can cause unnecessary and intermittent tripping. So, how can you eliminate or minimize the effects? A clamp meter is a necessary tool. However, make sure the clamp meter is suitable for leakage current.
Line Leakage Test
Although many experts use this name, it’s actually a current leakage test. This measurement is done during the electrical safety test of a device. The idea is to find any leakage current over acceptable limits. That current can go via the capacitor’s dielectric or the insulation surface.
Conclusion
So, you can see, it is leakage current, not voltage leakage. And, the experts suggest that the maximum leakage current should be 210mA in any custom cable assembly. It can be a serious problem if you don’t keep it in acceptable ranges. At Cloom, we provide help with cable assembles, so don’t hesitate to contact us if you have any questions!
