Damping

Attenuation in coaxial cables refers to the loss of signal amplitude that occurs from the initial to the final conductor. Each conductor in a coaxial cable acts as a transmitting antenna and radiates electrical power. It is therefore important to minimise this value, which is expressed in decibels (dB), by design. Attenuation increases with increasing frequency and cable length, which means that the signal level is reduced.

The higher the attenuation value and the frequency, the lower the useful signal at the end of the cable. The signal attenuation can be influenced by the length of the cable, whereby the shorter the cable, the better the signal at the end.

Important calculation formulae:

The damping (a) is determined by the following formulae:

• Power ratio: 𝑎=10⋅log10(𝑃1𝑃2)a=10⋅log10(P2P1) in dB
• Voltage ratio: 𝑎=20⋅log10(𝑈1𝑈2)a=20⋅log10(U2U1) in dB

1. Leistungsverhältnis: 𝑎=10⋅log⁡10(𝑃1𝑃2)a=10⋅log10​(P2P1​) in dB
2. Spannungsverhältnis: 𝑎=20⋅log⁡10(𝑈1𝑈2)a=20⋅log10​(U2U1​) in dB

These formulae make it possible to calculate the attenuation based on the ratio of the powers (P1 and P2) or the voltages (U1 and U2).

Comparison of the attenuation between two cables: Link