atcomsystems.ca/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Rural Hum Issues

Bill,
I'm beginning to agree with you. I'm not saying the issue is underground, just that the person a few hundred feet from where it goes under it fine, and then the person a few hundred feet from where it comes up has hum, as do the rest of the people on the road. (Rural area, rest of the people = 3 before the line ends).

It may or may not parallel power, there are power lines running the same way, but I don't know where the phone company line goes after it goes under.

We'll see, I will buy a choke if I have to, but I'd rather they buy it since it seems the issue is with their lines. Guess I'm done here for now, I'll update this thread with the outcome. Thanks for all the input!

I believe that Bill had the right idea....a broken bonding sheath will cause all kinds of troubles, from noise to not being able to LD call. There is a test unit that can test for that...and it only takes one lost bond/ground to allow the situation you describe.

Thanks for the input, everyone. One more comment, maybe it's completely irrelevant, but the audio on my analog line seems to be extremely muddy and missing the mid-range, when compared to other analog lines (at work), or my VoIP line (at home).

I did try removing the DSL filter, but the audio was still just as bad?

Hummmm you know enough to be dangerous don’t ya. Haha… One of the things I had to do when I came to the Telco side of the demarc was learning to think I bit differently than I had before with regards to electronics.

Here’s a couple of the finer points of a telephone service you missed on:

* On a Telco circuit the cable pair provides much of the circuit resistance. Touch the two wires together. We don’t care… It’s NOT a short. Just looks like an off-hook condition from this side. Completely dependant on loop length (and cable gauge) but there’s a few hundred ohms of resistance there in the pair.

* There is BOTH AC and DC current on a POTS line. The inductor of the primary side of your 1:1 transformer looks like “nothing” to the DC current. Current flows just like you’re “off-hook.”

* “Ground Lift” There’s a term I know as a guitar player. That sort of 60-cycle hum comes from grounds being at two different potentials for two different gain devises. (I.E. pre-amp & power amp on a different ground… Or active effect and pre/power-amp being on different grounds.) As mentioned before the “hum” you’re hearing is probably inducted on to the cable pairs. … Since I can tell you know what you’re talking about here in many regards, listen to the difference. The “60-cycle hum” from a powered audio circuit (Guitar amp, PA, etc.) is going to have a lot more harmonic frequencies in it. Induced power on a line is going to be a much flatter “hum.”

@CNG - Yes you are right, an audio circuit in a sound board has a very bright hum, where as the hum in my line is a very dull hum.

Hey, it's only coming to you at 300-3000 Hz... Don’t go throwing a parametric eq on it or anything.

Reading more of your detective work on this… I really do think as point out a few times on this thread, there is a missing bond (ground) on the line. Probably at or near where the cable goes from over-head to buried.

@CNG - The phone company claims they did grounding and bonding on the lines and all is in order. Now, let me get dangerous for a moment (going beyond what I know), should there be a ground on every telephone/electric pole?

Short answer, No. On true AC induction the farther out you go the louder the hum.

Every pole no... Every drop (access point) yes.

Call the PUC using you humming line and you will probably start getting some action. In the end, the hum is NOT your resposibility to troubleshoot or repair. You pay somewhere between $30 and $100 a month for a good clean usable phone line and you are not getting your money's worth! (It has been awfully hard to not say "It hums because it doesn't know the words" ) John C.