Why, do you think there's some sort of difference on aluminium lines?
There is, but how much and whether it would be obvious, I'm not sure of.
At higher frequencies the conductivity of some metals is reduced, one reason is the skin effect and that they form oxide layers which do not conduct. Silver for example is great at DC and low frequencies but as the frequency increases the advantages are lost. Aluminium does oxidise on the outer skin with potentially a similar effect.
So if the attenuation per tone group - D0, D1, D2, D3 or per tone could be plotted, would the gradient of Aluminium compared to copper be noticeably different?
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