said by Morac:
pstream Frequency: 36200108 Hz29399949 Hz22000000 Hz
Upstream bandwidth: 6400000 Hz6400000 Hz3200000 Hz
Is it possible for one of the 3 upstream channels to be having T4 errors, but the other 2 work okay?
For example your middle upstream channel is centered on 29.4 mhz and is 6.4 mhz wide. 29.4 - 3.2 (half the channel width) is 26.2 mhz. The CB radio frequencies are from 26.965 to 27.405 MHz, so the entire CB radio band is within that lower half of your middle upstream channel.
It's possible a crack in the cable is letting local CB interference or a local CB radio placed close to cable equipment is overpowering it's shielding.
This is a pretty common problem with cable systems running along major trucking routes.
It would've been better if the 29.4 Mhz channel was 3.2 Mhz wide and the 22 Mhz upstream was 6.4 Mhz wide... that would've left a gap from 25.2 to 27.8 Mhz for the CB band to fit into.--
If it's important, back it up... twice. Even 99.999% availability isn't enough sometimes.