Detailed Answer
Underground roadway metal supports and equipment cause severe signal shielding: signal attenuation is 10-30dB greater than ground, greatly shortening communication distance. Solutions: 1. Repeater networking (one level per 300-500m); 2. Antenna position optimization (roadway direction); 3. Low frequency band (470MHz better than 2.4GHz); 4. Link budget design. Lideral provides underground repeater solutions; Xingjia mine-area coverage.
| Attenuation | 10-30dB greater than ground |
| Countermeasure | Repeater networking |
| Band | 470MHz |
Note:Underground coverage solution must be designed by on-site measurement.