I would have thought contention would have no effect on cable attenuation.
The measured attenuation is calculated based on the physical reasons, power, resistance etc.
Contention is going to be based on the available bandwidth at any given time.
Could you have over stressed the cables when you were re-terminating them? We know the cables are of an extremely small cross section, so there is a potential that by bending the cable you could have created a week point, and a small increase in resistance?
Just a thought.
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