Cable Loss Calculator — LMR IoT Antennas
Calculate coaxial cable loss at any cellular frequency. LMR-100, LMR-240, LMR-400, RG58. Interactive calculator plus loss tables.
Cable Loss Calculator
Enter your cable type, run length, and operating frequency to calculate total cable loss. Results are approximate — actual loss depends on connector quality, cable temperature, and installation condition.
Cable Loss Reference Table
| Cable | 800 MHz | 1800 MHz | 2600 MHz | 3500 MHz | Max Rec. Run |
|---|---|---|---|---|---|
| LMR-100 | 0.20 dB/m | 0.31 dB/m | 0.42 dB/m | 0.54 dB/m | 2m (5G) / 5m (4G) |
| LMR-200 | 0.13 dB/m | 0.20 dB/m | 0.27 dB/m | 0.36 dB/m | 4m (5G) / 8m (4G) |
| LMR-240 | 0.08 dB/m | 0.13 dB/m | 0.18 dB/m | 0.23 dB/m | 7m (5G) / 15m (4G) |
| LMR-400 | 0.04 dB/m | 0.07 dB/m | 0.10 dB/m | 0.13 dB/m | 12m (5G) / 25m (4G) |
| RG-58 | 0.22 dB/m | 0.36 dB/m | 0.48 dB/m | 0.64 dB/m | Testing only |
Connector Loss
Add 0.1-0.3 dB for each connector pair (one antenna-side connector + one router-side connector). A good quality installed SMA connector pair adds approximately 0.15 dB. A corroded or poorly installed connector can add 2-5 dB — which is why outdoor weatherproofing matters more than cable type in many installations.
When to Upgrade Cable
If the calculator shows more than 2 dB total cable loss, consider LMR-400. If it shows more than 3 dB, upgrade is strongly recommended. At 3 dB loss, you have halved the signal power reaching the router — equivalent to halving the effective radiated power of the antenna. Most field engineers accept up to 2 dB cable loss as a reasonable trade-off against cable cost and flexibility.
Talk to Peter Green
Tell me your router model, location, and application. I will specify the right antenna.