sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Rural Hum Issues

@vad60 - i wish it was that easy. the hum is affecting several customer of Frontier's all within a several mile area, so I do not have any reason to believe it is my house wiring. I guess I try them one more time (has almost been two months) and if there is no resolution then we file a complaint with the PUC and see where it goes from there.

What are everyone's thoughts about filing an informal vs. formal complaint? I'm not afraid to stand-up and make a case. Would I have more power and pull if I filed a formal complaint and had all of the affected parties come before the PUC?

If you can measure that much AC to ground on an idle line, I'd tend to think that your case is open and shut with regard to a PUC filing.

Well I just discovered something interesting today. Right after the last house where the signal is clean, the cabling goes underground until it gets to the next house where there is hum!!! Sounds, to me, like there is an issue underground... ?water?... maybe that's why they've been dragging their feet!

Buried cable, especially if it is pre-1970's where it might not have been gel-filled is prone to water intrusion. That wouldn't likely be the cause for 8-10 volts AC to be measured to ground, but anything is possible.

I'm with Ed, water in the cable isn't going to give you an AC voltage reading. Wet pic won't do anything unless there is pair insulation damage then it will start to battery burn and eventually get all the pairs that have battery on them. This will cause a lot of static, shorts, and cross talk, but not a hum unless it touching the sheath then you'd get a ground hum, but still no AC voltage.

So can someone explain this? Tonight, getting antsy and wanting to put some of my electronics background to use, I wired up a 1:1 transformer and put a 600ohm resister in-line on the telco side. It seemed to work (e.g. passed audio, and telco didn't detect a short), however, I had a hum on the audio!

If the hum is being inducted in and is being caused by the AC on the line, shouldn't putting a 1:1 transformer in right before my phone produce a 'ground lift' and remove the hum?

Interestingly, if I remove the 600ohm resister, the telco detects a short, removes the dial-tone and then, if I remove my DSL filter I can hear the DSL... once it finally times out the line is crystal clear.

A 1:1 transformer is still going to pass AC and the associated audible hum. The resistance of the transformer and the resistor together must have been high enough to not be detected by the CO as an off-hook condition.

Remember that the DSL signal doesn't require a full pair to operate. It actually rides on one side of the line to act as an antenna to carry the signal. Once the CO times out and goes silent, you are probably hearing the DSL signal to ground (a noisy one at that).

Since you didn't mention DSL until now, I must ask: Does (did) your DSL service work? Maybe we have an issue with a DSLAM and not cable trouble at all.

Yes, DSL works fine. I was hearing the DSL yes, but it finally times out and then I can hear silence...

Here is what I HAVE figured out:
* I have sampled 4 people on the road I live.
* 3 of them have DSL
* 1 of them does not have DSL
* 2 of the DSL folks have hum, one does not.
* 1 without DSL has hum.

* When I shorted out the dial-tone line, and removed the DSL filter, I could hear the DSL until it finally timed out and gave up, at which point the line was silent and had no humming.

As a point of clarification for what I said above, right after the line feeds the person with DSL but without hum it goes underground for about 3/4 of a mile, then comes up and feeds the one person without DSL but with a hum.

It was mentioned that a wet line won't cause a hum, but what if there was a powered repeater (load coil) type of item down under ground?

Just thought of something, we just got DSL, about 6 months ago, and no new digging, so presumably there is no load coil underground.

I just e-mailed the area supervisor to ask if they tried using a TDR on the lines to detect any breaks.

Guess we will see what comes of all of this.

Load coils aren't powered and they aren't going to bury a repeater, they more than likely wouldn't bury a load in that short of distance.

Way I see it either you're going to fix this with a choke or the phone company is. I don't think the fact that it goes buried has squat to do with it unless it parallels power and there's a break in the sheath.

I do know we had "mystery" AC hum on a cable where a contractor coiled some cable and buried it so he got credit for more footage, just made one big inductor.