Coaxial cable loss calculator
About
This calculator works out the power lost in coaxial cables and connectors at different frequencies. You can add cables, connectors and attenuators one after another to model your actual antenna system.
It carries the specifications of common Ukrainian and international cables.
| Item | Description | Length, m | Actions |
|---|---|---|---|
| Nothing added yet. | |||
| Frequency | Loss, dB | Loss, % | Output power, W |
|---|---|---|---|
| Fill in the form above to get the figures. | |||
Notes:
- System elements: add cables, connectors and attenuators in the order they are connected.
- Cable length: given in metres to the nearest centimetre (0.01 m).
- Number of connectors: a whole number (2 connectors, for instance).
- Loss calculation: linear interpolation between the tabulated frequencies.
- Colour coding of the result:
- 🟢 Green: less than 50 % lost (acceptable)
- 🟡 Yellow: 50–80 % lost (worth attention)
- 🔴 Red: more than 80 % lost (serious)
- Cable types:
- RG-58: thin cable for HF/VHF (50 Ω)
- RG-8: thick cable for HF (50 Ω)
- LMR-400: low-loss cable for VHF/microwave (50 Ω)
- RG-213: thick general-purpose cable (50 Ω)
- RG-174: very thin cable for microwave (50 Ω)
- RK 50: Soviet and Ukrainian cables (50 Ω)
- 3D-FB: semi-rigid cable for microwave (50 Ω)
- Conductors:
- Solid: better at high frequencies
- Stranded: more flexible, worse loss at microwave
- Calculation frequencies: 1.9, 3.75, 7.15, 14.15, 27.5, 52, 145, 435 MHz
- Accuracy: the results are approximate and depend on the quality of the cable and of the assembly
- Recommendations:
- Keep cables as short as you can
- Use as few connectors as possible
- For VHF and microwave use LMR-400 or equivalent
- Check the system SWR once it is assembled
Where the data comes from
Cable and connector specifications are taken from:
- Manufacturers' datasheets
- Measurements made by radio amateurs
- Catalogues of Ukrainian suppliers
- International standards
Useful links
© 2026 UR3PKI · CyberDev.Space · Content licensed under CC BY-NC-SA 4.0.
How to cite this calculator
UR3PKI. «Coaxial cable loss calculator». CyberDev.Space. https://cyberdev.space/en/radio/calculators/others/coax_loss_calculator (licence CC BY-NC-SA 4.0).The licence lets you use this material freely, including in teaching materials, but only with attribution to the author and a link to the source.