Compare radiating (leaky feeder) cables for a tunnel, mine or in-building run, and see which ones deliver the signal you need at the end of the cable.
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Walkthrough
Choose the coupling loss percentile, the fire and smoke rating the project requires, the jacket material and the maximum cost tier.
The top recommendation shows the predicted signal at the end of the run and the margin against your minimum. Cables with estimated curves are marked.
The breakdown shows longitudinal loss, coupling loss, distance falloff, total path loss and the longest passive run the cable could support.
Every cable is listed against the same inputs with its losses, predicted signal, margin, jacket, fire ratings and indicative cost. Cables that fail a filter show the reason.
Each cable shows its datasheet details, a link to the published datasheet and where each curve came from, including the test standard and review date.
Pick up to four cables to compare, including ones that did not pass your filters. With nothing picked, the comparison shows the top passing cables.
Inputs with the top recommendation and link breakdown.
Overview
Radiating cable, also called leaky feeder or LCX, is coaxial cable with slots that let a controlled share of the signal leak out along its length. It provides radio coverage in tunnels, underground mines and buildings where antennas cannot reach. Each cable trades longitudinal loss, coupling loss, size, weight, bend radius, jacket material and fire rating differently, so choosing one for every project takes time.
The Leaky Feeder Cable Selector does that comparison for a single passive run. Enter the operating frequency, run length, head-end power, minimum signal level and distance from the cable, and the tool reads each cable's datasheet curves at your frequency. It predicts the signal a radio receives at the end of the run, compares it with your minimum, and ranks the cables that pass.
Filters for application, fire and smoke rating and jacket material remove cables that do not suit the site, with a reason given for each one. Every cable shows its datasheet details and where its data came from, and a figure the maker does not publish reads not published. For an amplified run over a longer distance, take the chosen cable into the Amplifier Spacing Calculator.
Cables come from the noIM₃ component catalogue, which holds manufacturer datasheet curves for radiating cables from makers such as RFS, ZCG Scalar and Benelec. Each entry carries longitudinal loss and coupling loss against frequency along with its physical and fire rating details.
The tool subtracts the longitudinal loss over the run, the coupling loss at your frequency and the distance falloff from the head-end power. The result is compared with your minimum signal level to give a margin for each cable.
Datasheets give coupling loss as a median (50 per cent) and a planning (95 per cent) figure. Choose the 95 per cent figure for a conservative design or the median to see typical performance.
Filter by application, fire and smoke rating and jacket material. Cables that fail a filter stay in the list with the reason shown, so you can see why each one did not qualify.
Each result shows total path loss and the longest passive run the cable could support. A frequency outside the rated band, or outside the points the datasheet publishes coupling for, fails rather than being extrapolated, and no gain is credited for a listener closer than the datasheet reference distance.
Compare up to four cables on physical and electrical specifications, predicted signal and margin. Tables of longitudinal loss and coupling loss across a range of frequencies help when a system covers more than one band.
Each cable lists its datasheet source, test standard and review date. A figure the maker does not publish is shown as not published, never filled in, and where a maker states coupling only as a nominal with a tolerance the page shows that statement and does not rank the cable as passing.
Inputs and outputs
Inputs 9
Outputs 10
Use cases
Cables that pass every filter are ranked by end-of-run margin over your minimum signal level, so the cable with the most headroom comes first. Loss and coupling are shown alongside to judge by eye. Cables that fail a filter are listed below the passing ones with their reasons.
Coupling loss is the difference between the signal inside the cable and the signal received at a reference distance from it. The received level varies along the cable, so manufacturers publish it statistically. The 50 per cent figure is the median, and the 95 per cent figure is the loss not exceeded at 95 per cent of points along the cable, which makes it the more conservative choice for design.
It is a planning estimate for a single passive run. Real coupling varies with the tunnel cross-section, how the cable is mounted and reflections from nearby surfaces, so confirm the design with a walk test once the cable is installed. For an amplified run use the Amplifier Spacing Calculator, and for site-specific coverage use the Leaky Feeder 3D Coverage tool.
Linearly in frequency between the points the datasheet publishes, as the Leaky Feeder Designer and the 3D coverage tool read them. Outside those points the figure is not on the datasheet, so the cable fails at that frequency rather than being extrapolated.
It depends on the project specification and the authority having jurisdiction. The filter checks each cable against the rating it carries on its datasheet, so a cable is only shown as passing when the manufacturer declares that rating. Confirm the requirement with the project specification before ordering.
The cables load from the noIM₃ component catalogue, which is built from published manufacturer datasheets. Each cable shows its datasheet source, and a figure the maker does not publish reads not published. No maker publishes a cable price, so the tool carries none: get a supplier quote before pricing a job.
The ranking runs in your browser, and your inputs are remembered in this browser between visits. The cable library is loaded from the noIM₃ component catalogue when the tool opens, but your project details are not sent to the server.
Related
Free on a Standard account, with no time limit. No credit card.
