Cable Length & Signal Attenuation Calculator
Calculate signal attenuation (signal loss) over a given cable length based on cable type, frequency, and cable specifications.
Leave blank to calculate attenuation only.
Formulas Used
Cable Attenuation:
Acable = α × L / 100
Where α = attenuation coefficient [dB/100m], L = cable length [m].
Frequency-Dependent Coefficient (Coaxial & Twisted Pair):
α(f) = αref × (f / fref)k
Where αref is the reference attenuation at fref, and k ≈ 0.5 (coaxial, skin-effect dominated) or ≈ 0.59 (twisted pair, per TIA-568).
Total Attenuation:
Atotal = Acable + Nconn × Aconn
Output Power:
Pout [dBm] = Pin [dBm] − Atotal [dB]
P [W] = 10(P[dBm] / 10) × 0.001
Assumptions & References
- Coaxial cable attenuation follows a square-root frequency dependence (skin effect): α ∝ f0.5 (Pozar, Microwave Engineering).
- Twisted-pair (Cat5e/6/6a) attenuation uses exponent k = 0.59 per TIA/EIA-568-C.2 standard.
- Reference attenuation values sourced from Belden, CommScope, and Corning datasheets.
- Single-mode fiber: ~0.35 dB/km at 1310 nm; ~0.20 dB/km at 1550 nm (ITU-T G.652).
- Multi-mode fiber (OM3/OM4): ~3.5 dB/km at 850 nm (TIA-492AAAC).
- Connector/splice losses are typical values; actual losses depend on installation quality.
- Temperature, bending, and aging effects are not included in this model.
- Attenuation is assumed uniform along the cable length.