Different line attenuation figures for broadband upload and download I would be interested to know why the line attenuation figures differ so much for upstream and downstream communication when the same copper/fibre cable is being used for the link to my house? ![enter image description here]( PS Apologies for the tag “routing” as I could not find a suitable one for my question.

Attenuation is dependent of frequency.

For example, the following is the Attenuation vs. Frequency for an RG-8 (coaxial) cable:

![enter image description here](

At 1Mhz the Attenuation is 0.1 dB for each 100 Feet.

At 100 Mhz is 1 dB for each 100 Feet

At 1 Ghz is around 5 dB for each 100 feet.

dB is a logarithmic measure, so these differences are **huge**.

Your Downstream speed (64286 kbps) uses signals in **higher frequencies** , maybe hundreds of Mhz.

Your Upstream speed (18782 kbps) maybe is located below 10 Mhz, so the attenuation is **higher** for downstream.

Here is other graphic involving multiple types of cable:

![enter image description here](