Underground Mine Leaky Feeder Coaxial Communication Cable (50 / 75 Ohm)
Flame-retardant 50 Ohm and 75 Ohm radiating leaky feeder coaxial communication cables engineered for underground hard-rock mines, coal mines, railway/highway tunnels and shaft HoistCom systems. Supplied in 1/2-inch, 7/8-inch and 1-1/4-inch slotted corrugated copper-tube trunk designs as well as flexible braided-slot 75 Ohm / 50 Ohm VHF/UHF leaky feeder designs, with optional integrated figure-8 galvanized steel messenger wire, low-loss physically foamed PE dielectric and flame-retardant PVC, PE or halogen-free LSZH outer jackets.
Because VHF and UHF radio waves attenuate rapidly around underground mine bends, crosscuts and rock pillars, underground voice dispatch, personnel tracking, tele-remote LHD control and leaky-feeder Ethernet/LTE data networks rely on radiating coaxial leaky feeder cables strung along drift backs and haulage roadways. Acting as a continuous bidirectional antenna, the leaky feeder leaks a controlled fraction of RF energy through precision-milled slots or an open-aperture outer conductor while propagating the main signal over kilometres of drift.
TEBAOFLEX supplies both 50 Ohm (standard for 150–900 MHz UHF/LTE/TETRA and radiating trunk systems) and 75 Ohm (standard for 150–175 MHz VHF mine leaky-feeder two-way radio systems with line amplifiers every 350–500 m) underground leaky feeder constructions. Each cable features a solid copper or copper-clad aluminum center conductor, nitrogen-injected low-loss physically foamed polyethylene (FPE) dielectric, and a precision-slotted copper foil/corrugated copper tube or controlled-aperture copper braid outer conductor.
For fast one-pass installation on mine roof bolts and rib hooks, self-supporting figure-8 messenger constructions mold a high-tensile galvanized steel wire rope (typically 7×0.8 mm to 7×1.6 mm, breaking load 3.5 to 12 kN) integrally alongside the flame-retardant yellow, orange, blue or black PVC, PE or halogen-free LSZH outer jacket.
Specify your system impedance (50 Ω or 75 Ω), operating frequency band (VHF 150 MHz, UHF 450 MHz or 800–2400 MHz), nominal cable size, messenger option and jacket colour with your enquiry. TEBAOFLEX supplies leaky feeder cables from a 50 m minimum order quantity with a standard lead time of 7–45 working days.
Explore the mining and tunneling cable range for related configurations.
For related underground mine telemetry trunk cables and screened low-voltage signal lines, compare these designs: P1209 Accessor Trunk Cable for Underground Mine Monitoring Systems (for 3-core copper-and-steel armoured trunk buses in underground mine monitoring systems); 2YSLGCGOEU 250/250 V Signal and Control Cable (for 250/250 V screened flexible control and instrumentation circuits on mining machinery). Confirm characteristic impedance (50 or 75 Ohm), VHF/UHF attenuation, and slot aperture geometry before ordering.
Construction
The representative construction illustrates Figure-8 Self-Supporting 1/2-Inch (and 75 Ω VHF) Underground Mine Leaky Feeder Coaxial Cable: a solid copper-clad aluminum or bare copper center conductor surrounded by white low-loss physically foamed polyethylene (FPE) insulation and a precision-slotted copper outer conductor, joined by an extruded web to a parallel 7-strand galvanized steel suspension messenger wire inside a high-visibility yellow flame-retardant outer jacket.
| Component | Material and construction |
|---|---|
| Inner center conductor | Solid bare copper (BC) or high-conductivity copper-clad aluminum (CCA) wire (2.6 mm to 13.1 mm diameter depending on 75 Ω / 50 Ω trunk size). |
| Low-loss foam dielectric | Nitrogen-injected physically foamed polyethylene (FPE) with ≥ 80% velocity of propagation and moisture-resistant closed-cell structure. |
| Radiating outer conductor | 50 Ω / 7/8" & 1-1/4" Trunk: annularly corrugated copper tube or longitudinal copper tape with precision-milled radiating slots. 75 Ω VHF Mine Feeder: longitudinal slotted copper-polyester tape or controlled-coverage copper braid. |
| Integrated messenger wire (optional Figure-8) | High-tensile stranded galvanized steel wire rope (e.g., 7×1.0 mm or 7×1.2 mm, 4.5–8.0 kN breaking strength) encapsulated in a figure-8 web for direct suspension on mine roof bolts. |
| Outer jacket | High-visibility yellow, orange, blue or black flame-retardant PVC, abrasion-resistant PE or halogen-free low-smoke (LSZH per IEC 60332-1-2 / IEC 60332-3-24) outer sheath. |
Applications
Select 75 Ohm VHF leaky feeder cable for classic 150–175 MHz underground mine two-way radio and line-amplifier trunks, or 50 Ohm 1/2", 7/8" and 1-1/4" slotted coaxial cable for multiband VHF/UHF/TETRA/LTE/Wi-Fi underground communication backbones.
- Underground hard-rock metal mines (gold, copper, nickel, zinc) and coal mine main haulage roadways, declines and working stope headings.
- VHF (150–175 MHz) and UHF (400–900 MHz) leaky-feeder two-way voice radio, emergency evacuation paging and mine-wide personnel/vehicle tracking.
- Tele-remote LHD loader and jumbo drill video/data control links and underground LTE / Wi-Fi / IoT broadband radiating backbones.
- Roadway, railway, metro and hydro-power tunnel construction communication systems requiring figure-8 self-supporting suspension.
For broader underground mining cable architectures and longwall face signalling circuits, review these engineering resources: Mining Cable Solutions for Mobile Equipment and Tunneling (for coordinated power, control, and communication cable planning across tunnels and mine headings); Longwall Signal and Mine Lighting Cable — 50 V / 110 V (for 50 V and 110 V auxiliary lighting and pull-cord signalling along underground longwall conveyors). Verify line-amplifier spacing, messenger wire tension, and flame-retardant sheath requirements for tunnel installation.
Specifications
| Parameter | Value |
|---|---|
| Characteristic impedance | 50 ± 2 Ω (50 Ohm series) or 75 ± 3 Ω (75 Ohm VHF mine series) |
| Operating frequency band | 75 Ω VHF series: 30–300 MHz (optimized at 150–175 MHz); 50 Ω Slotted Trunk series: 30–2,700 MHz (VHF, UHF, TETRA, LTE) |
| Velocity of propagation | 81% to 88% (nitrogen-injected physically foamed PE dielectric) |
| Coupling loss (at 2 m, 50% / 95% probability) | Typically 55–65 dB / 62–72 dB at 150–450 MHz |
| Minimum installation bending radius | 10 × cable minor diameter (single bend); 15 × to 20 × cable minor diameter (repeated re-hanging) |
| Messenger wire breaking load (Figure-8) | 4.5 kN (7×1.0 mm galvanized steel) up to 8.5 kN (7×1.2 mm) or 12 kN (7×1.6 mm) |
| Operating temperature & flame retardancy | -30 °C to +70 °C (-40 °C PE option); flame-retardant per IEC 60332-1-2, IEC 60332-3-24 or MT 386 |
| Commercial supply terms | Minimum order quantity 50 m (standard 350 m / 500 m amplifier-span reels available); manufacturing lead time 7–45 working days |
| Model & nominal size | Impedance & construction | Inner / outer conductor Ø (mm) | Overall jacket size — Ø or Figure-8 H × W (mm) | Attenuation at 150 MHz / 450 MHz (dB/100 m) | Attenuation at 900 MHz (dB/100 m) | Coupling loss 50% / 95% at 150–450 MHz (dB) | Approx. weight (kg/km) |
|---|---|---|---|---|---|---|---|
| LF-75-7 (RG-6 Leaky) | 75 Ω Braided/Slotted VHF | 1.35 / 6.2 | 8.8 | 6.8 / 12.4 | 18.5 | 58 / 65 | 95 |
| LF-75-7-M (Figure-8) | 75 Ω VHF + Steel Messenger | 1.35 / 6.2 | 8.8 × 14.8 | 6.8 / 12.4 | 18.5 | 58 / 65 | 165 |
| LF-75-9 (SYWV-75-9) | 75 Ω Slotted VHF Mine Trunk | 2.15 / 9.8 | 12.5 | 4.3 / 7.9 | 11.8 | 56 / 64 | 180 |
| LF-75-9-M (Figure-8) | 75 Ω VHF + 7×1.0 Messenger | 2.15 / 9.8 | 12.5 × 19.5 | 4.3 / 7.9 | 11.8 | 56 / 64 | 265 |
| LF-75-10 (RG-11 Leaky) | 75 Ω Classic Mine VHF Trunk | 2.60 / 11.5 | 14.5 | 3.4 / 6.4 | 9.6 | 55 / 63 | 235 |
| LF-75-10-M (Figure-8) | 75 Ω VHF + 7×1.2 Messenger | 2.60 / 11.5 | 14.5 × 22.0 | 3.4 / 6.4 | 9.6 | 55 / 63 | 345 |
| LF-75-12 (1/2" 75 Ω) | 75 Ω Low-Loss Slotted Copper | 3.15 / 12.7 | 15.8 | 2.9 / 5.4 | 8.1 | 57 / 65 | 280 |
| LF-75-12-M (1/2" 75 Ω Fig-8) | 75 Ω Slotted + 7×1.2 Messenger | 3.15 / 12.7 | 15.8 × 23.5 | 2.9 / 5.4 | 8.1 | 57 / 65 | 395 |
| RMC-50-3/8" (LF-50-9) | 50 Ω Slotted Corrugated Copper | 2.60 / 9.5 | 12.2 | 4.2 / 7.6 | 11.2 | 56 / 63 | 175 |
| RMC-50-3/8"-M (Figure-8) | 50 Ω 3/8" + 7×1.0 Messenger | 2.60 / 9.5 | 12.2 × 19.2 | 4.2 / 7.6 | 11.2 | 56 / 63 | 260 |
| RMC-50-1/2" (LF-50-12) | 50 Ω 1/2" Slotted Corrugated | 4.80 / 13.8 | 16.2 | 2.7 / 4.9 | 7.3 | 58 / 65 | 265 |
| RMC-50-1/2"-M (Figure-8) | 50 Ω 1/2" + 7×1.2 Messenger | 4.80 / 13.8 | 16.2 × 24.0 | 2.7 / 4.9 | 7.3 | 58 / 65 | 380 |
| RMC-50-7/8" (LF-50-22) | 50 Ω 7/8" Slotted Main Trunk | 9.10 / 24.9 | 28.0 | 1.5 / 2.8 | 4.2 | 60 / 67 | 540 |
| RMC-50-7/8"-M (Figure-8) | 50 Ω 7/8" + 7×1.4 Messenger | 9.10 / 24.9 | 28.0 × 37.5 | 1.5 / 2.8 | 4.2 | 60 / 67 | 695 |
| RMC-50-1-1/4" (LF-50-32) | 50 Ω 1-1/4" Tunnel Backbone | 13.1 / 36.0 | 39.8 | 1.1 / 2.1 | 3.2 | 62 / 69 | 960 |
| RMC-50-1-1/4"-M (Figure-8) | 50 Ω 1-1/4" + 7×1.6 Messenger | 13.1 / 36.0 | 39.8 × 50.5 | 1.1 / 2.1 | 3.2 | 62 / 69 | 1,160 |
These are the standards this construction is designed and manufactured to (IEC 61196-4 radiating coaxial cable specifications, TB/T 3201 and MT/T 1105 underground leaky feeder principles).
Longitudinal attenuation values are stated at +20 °C ambient temperature; underground line amplifiers are typically spaced every 350 m to 500 m to compensate for longitudinal loss.
High-visibility yellow, orange or blue jackets are commonly used underground to distinguish trunk leaky feeder lines from branch stope lines and power cables.
Standards
| Standard or specification | Application |
|---|---|
| IEC 61196-4 | Coaxial communication cables — Part 4: Sectional specification for radiating cables (leaky feeder attenuation, coupling loss and VSWR test methods). |
| IEC 60332-1-2 & IEC 60332-3-24 | Single and bunched vertical flame propagation tests for underground tunnel and mine communication cables. |
| IEC 60754-1 / IEC 61034 | Halogen-free acid gas emission and low smoke density performance for LSZH tunnel/mine leaky feeder jackets. |
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