Coaxial Cable Loss
Estimate the attenuation of a coaxial cable run (RG-58, RG-213, LMR-400, Heliax…) from the cable type, the frequency and the length. It interpolates the loss by √f from nominal factory data. Everything in your browser.
The loss at other frequencies
| Frequency | dB/100 m | Run |
|---|
The highlighted row is your frequency. The rest is interpolated the same way, by √f.
The same run on other cables
| Cable | dB/100 m | Run loss |
|---|
At your frequency and length. Handy to decide whether a better cable is worth it.
How it is calculated · √f and approximate values
1. Each cable comes with its nominal attenuation
in dB/100 m at a few reference frequencies (factory data).
2. Coaxial loss grows with the square root of
frequency (resistive loss): atten(f) ≈ atten(f₁)·√(f/f₁).
Between two references we interpolate linearly in √f.
3. Total loss:
dB = atten(f)/100 × length(m). This is the cable's own loss;
it excludes connectors and adapters (each adds ~0.1–0.5 dB).
4. Every 3 dB is half
the power; 10 dB leaves 1/10.
The values are approximate: they vary by manufacturer,
temperature and cable quality.
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