Something caused reconnect and change of circuit parameters.
Hmm . . . then I don't think we will be able to say what was the underlying cause. (A technician could have been working on a large joint-closure, for example.)
I'm not sure but I think that larger distribution cables are deployed in ducts. These cables are under the pavement.
Yes, I understand. Thank you.
Is it possible that shunt fault causes high attenuation on two frequency ranges 33-50, 250-511 (on abnormal Hlog upstream frequiences and 150-511) relative to the other frequiences? I've read that shunt fault causes high attenuation on higher frequiences relative to lower frequiences. I see however two ranges: one low frequiences, second high frequiences.
A series capacitive fault would behave as a high pass filter. Attenuating low frequencies but allowing higher frequencies to pass.
A shunt capacitive fault would show behaviour similar to a low pass filter. Attenuating high frequencies but allowing lower frequencies to pass.
You make reference to three bands of sub-carriers; 33 - 50, 250 - 511 & 150 - 511. Let's calculate the equivalent frequencies --
sub-carrier frequency (kHz) |
33 142.3125 |
50 215.625 |
150 646.875 |
250 1078.125 |
511 2203.6875 |
Looking at the frequencies displayed in that table, I am having great difficulty in convincing myself that either of the two ranges (which you have mentioned) could both be
simultaneously subject to increased attenuation as a result of a change in capacitive shunt effect.
I spent some time looking at the formulae on the
RLC circuit Wikipedia page which eventually convinced me that what you have observed cannot be due to just an increase (or decrease) in shunting capacitive effect. Try as I might, I cannot find any other possible explanation.
My overall feeling is that this is another case where I have to say: "Sorry, I just do not know".