What does it mean if a cable has an attenuation of 3 dB?

When a cable has an attenuation of 3 dB, it indicates that the signal strength has been reduced by half. In decibel terms, a reduction of 3 dB corresponds to a halving of the power. This is a fundamental principle in signal processing and telecommunications where decibels (dB) are used to express ratios of power or intensity.

To clarify the concept further, when a signal's power is measured in dB, a decrease of 3 dB means that only 50% of the original power remains after traversing the cable. This is critical to understand in contexts such as networking and communications, where maintaining signal strength is essential for effective data transmission. Therefore, a statement regarding a cable's 3 dB attenuation correctly conveys that it retains half of the original power, reflecting a significant impact on the signal quality.