Coax Loss Calculator
Calculate signal loss and power delivery for common coaxial cables
About Coaxial Cable Loss
- Coax loss increases with frequency - higher bands have more loss
- Loss increases with cable length
- Better quality (lower loss) cable costs more but delivers more power to your antenna
- At VHF/UHF, even small runs can have significant loss with poor cable
- Loss is measured in decibels (dB) - 3 dB = half power lost
Calculate Your Coax Loss
Coax Comparison Table
Loss values in dB per 100 feet at various frequencies
| Cable Type |
Diameter |
10 MHz |
50 MHz |
144 MHz |
440 MHz |
1296 MHz |
Notes |
| RG-58/U |
0.195" |
1.4 |
3.3 |
5.8 |
11.0 |
20.5 |
Cheap, high loss, avoid for VHF/UHF |
| RG-8X |
0.242" |
1.2 |
2.8 |
5.0 |
9.5 |
17.5 |
Mini-8, flexible, moderate loss |
| RG-213 |
0.405" |
0.7 |
1.6 |
2.9 |
5.5 |
10.5 |
Standard quality, good for HF |
| RG-8 |
0.405" |
0.6 |
1.5 |
2.7 |
5.2 |
9.8 |
Better quality than RG-213 |
| LMR-195 |
0.195" |
1.2 |
2.7 |
4.9 |
9.0 |
16.9 |
Small, flexible, low-loss alternative to RG-58 |
| LMR-240 |
0.240" |
0.9 |
2.0 |
3.7 |
6.9 |
13.0 |
Better than RG-8X, flexible |
| LMR-400 |
0.405" |
0.4 |
0.9 |
1.7 |
3.3 |
6.6 |
Excellent all-around choice |
| LMR-600 |
0.590" |
0.3 |
0.7 |
1.3 |
2.5 |
4.9 |
Very low loss, heavier/stiffer |
| LDF4-50A |
0.630" |
0.2 |
0.5 |
0.9 |
1.8 |
3.6 |
Hardline, commercial grade |
| LDF5-50A |
0.875" |
0.1 |
0.3 |
0.6 |
1.2 |
2.5 |
Hardline, minimum loss |
| Belden 9913 |
0.405" |
0.4 |
1.0 |
1.9 |
3.8 |
7.5 |
Popular low-loss choice |
💡 Choosing the Right Coax
- HF (160m-10m): RG-8, RG-213, or LMR-400 work well for most installations
- VHF (6m, 2m): Use LMR-400 or better. Avoid RG-58 for long runs
- UHF (70cm and above): LMR-400 minimum, LMR-600 or hardline for longer runs
- Short mobile runs: RG-8X or LMR-240 offer good flexibility
- Rotator loops: Use flexible cable like LMR-240 or LMR-400-UF
- Weatherproofing: Use quality connectors and seal with coax-seal or self-amalgamating tape
- Cost vs. Performance: Better cable costs more but lasts longer and performs better
⚠️ Important Considerations
- Loss values assume proper installation and good quality cable
- Damaged, kinked, or water-damaged cable will have higher loss
- Connectors add loss - use quality connectors and proper installation
- Loss is cumulative - every adapter, connector, and splice adds loss
- Check your cable periodically - UV damage and moisture increase loss over time
- At legal limit power (1500W), use appropriate cable to avoid heating and damage
