Predict leaky feeder radio coverage across a 3D underground mine, including the drifts the cable does not reach, for downlink, uplink and the two together.
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Walkthrough
Choose the radiating cable and radio system, then set the channel plan with the AGC pilot and the downlink and uplink traffic carriers.
Hover over any point for the downlink, uplink and pilot levels, or over an amplifier for its input, gain and output.
Slice the view to one level at a time to find the weakest run on each, check the design criteria, and export the project as a file when needed.
A multi-level mine model with the leaky feeder cable.
Overview
Leaky feeder (radiating cable) is the usual way to provide radio coverage underground. The cable runs along the main drives and leaks signal along its length, so radios have coverage wherever the cable goes. The harder questions are off the cable: how far signal reaches into crosscuts and stope accesses that carry no cable, where the cable loss has built up enough to need another amplifier, and whether a worker at the far end can talk back as well as hear. A single cable run calculation cannot answer those across a multi-level mine.
The 3D Leaky Feeder Coverage tool works on a three-dimensional model of the mine. You can import centreline geometry from a mine planning package or GIS, draw drifts, declines and stopes in the scene, or start from a built-in demonstration mine. The cable can be routed automatically along the main drives or laid by hand with power splitters, and amplifiers can be placed individually or spaced automatically.
Coverage is shown as a heatmap along the floor of every drift. On cabled drifts it combines the signal on the cable with the datasheet coupling loss, distance from the cable and body loss. Drifts without cable are fed by corner diffraction from the nearest cabled junction, using ITU-R P.526, and corridor propagation along the drift, using ITU-R P.1238. Downlink, uplink and the weaker of the two can each be shown at a reliability percentile you choose, with coverage statistics and a pass or fail check against your design criteria.
Import centreline geometry from DXF, CSV, KML, GeoJSON or the native file format, with a validation report before anything is accepted. You can also draw drifts, declines, raises, shafts and stopes in the scene, or start from a built-in demonstration mine.
Let the tool route the radiating cable along the main drives, or draw the runs yourself, place power splitters and set the head end. Splitter losses are carried to every branch downstream.
A channel plan holds the AGC pilot and the downlink and uplink traffic carriers, and coverage is assessed on the highest frequency channel in each direction. Inline amplifiers come from the noIM₃ component catalogue and can be placed by hand or spaced automatically, with saturation flagged.
Crosscuts, stope accesses and dead ends that carry no cable receive signal by corner diffraction calculated with the ITU-R P.526 uniform theory of diffraction. Propagation along those drifts follows the ITU-R P.1238 corridor model.
Downlink shows what a handheld receives, uplink shows what reaches the cable when a handheld transmits, and two-way shows the weaker of the two. This finds places where a worker can hear the base station but cannot be heard.
Coverage is shown at the median or 95 per cent, the two coupling figures datasheets publish, or at 90 per cent, derived on a lognormal spread between them. 99 per cent is not assessed on the published figures; it needs a decay law calibrated from site measurements. Optional settings cover the noise environment for a signal to noise check, extra coupling loss for harsh drift conditions, rock type and an installation margin, and a pass or fail verdict tests the design against your required coverage.
Slice the view to one level at a time to find the weakest run on each. Hovering over any point shows the downlink, uplink and pilot levels, and hovering over an amplifier shows its input, gain and output.
Designs save automatically in your browser and to your account, and a project exports as a self-contained file with the mine geometry included. Mines can also be kept in a named library in your browser.
Inputs and outputs
Inputs 11
Outputs 10
Use cases
On cabled drifts it follows the signal along the cable through splitters and amplifiers, then subtracts the datasheet coupling loss, the distance falloff to the receiver, body loss and the traffic carrier back-off from the pilot. On drifts without cable it calculates corner diffraction with ITU-R P.526 and propagation along the drift with ITU-R P.1238. The result is classified into signal level bands at the reliability percentile you choose.
Yes. The cable can be routed automatically along the main drives, or you can switch to manual mode, draw your own runs, place splitters and set the head end. The drawn cable then drives the coverage prediction.
The AGC amplifiers hold the pilot at a fixed level, while the voice and data carriers usually run some decibels below it to protect amplifier headroom. The heatmap shows the carrier a worker actually uses, and the pilot is reported separately. Coverage is assessed on the highest frequency channel in each direction because that channel has the most loss.
The import reads 3D DXF centreline strings from mine planning packages, waypoint CSV, KML and GeoJSON lines, and the tool's own JSON format. Each import is checked for joins, levels, connectivity and units, and a report is shown before it is accepted. Without a file, you can draw the mine in the scene or start from the demonstration mine.
Downlink is the signal a handheld receives from the system. Uplink is the signal that reaches the cable and the system when the handheld transmits, which is often the limiting direction. The two-way view shows the weaker of the two at each point, so it marks every place where the radio link fails in either direction.
This tool gives the spatial coverage picture across a whole mine. The Leaky Feeder Designer is a schematic design tool for the detailed cascade, with multi-carrier signal levels, intermodulation, DC power feed and per-radio link budgets. Many projects use both.
The tool is in beta. The cable is modelled as a tree, so a loop in the drift network is cabled along one path and the choice is disclosed. Some DXF entities such as arcs and splines are skipped and counted, coupling loss above a cable's characterised band is held at the band edge, and bend loss and polarisation are not modelled. The results support design decisions and do not replace site measurement.
Coverage is calculated in your browser. The cable and amplifier data load from the noIM₃ component catalogue, and projects are saved in your browser and to your account. Mines in the named library are kept in your browser and are included in exported project files.
Related
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