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

I'm having an issue with 'Rural Hum'. Since we moved in to our new house about 40 days ago, our line has had hum. It has tested with hum at the NID with all inside lines and phones disconnected and has about 8-10 volts of AC current on the Ring-to-Ground.

The hum is bad enough that it is hard to hear quiet calls, and people have said they sometimes can not hear us.

The telephone company had come out and did the following:
** The last 3 or 4 spans of cable to our house are non-shielded cable. Tech suggested replacing it. They decided they didn't need to replace it.

** Grounding and bonding was done at each pole to by-pass the power grounds (though I realize it is still in the same soil area)

** Line went through a loop extender in the office years ago. Has not been used in ages. At the start of the circuit it had 60mA of current, but coming out of the extender it only had about 30mA of current. Loop extender was taken out.

** Power Company: The crew found a lightening arrester that might have blown out and was laying against the pole, and they replaced that. The bottom part of the lightening arrester was blown and laying against the ground wire.

Tonight I had the following correspondence with the phone company:
We met with the electric company and they were to replace some equipment. I am told prior to this meeting we are well within specs. This may be the best the situation can deliver. Let me know your thoughts.

We'll I've got some thoughts.... but before I voice them, what input can anyone give me here? Do I have any legal basis with the PUC to get this line resolved, or do you think the hum really is "within specs"?

Are there any plans anywhere for using something like a 1:1 transformer and resistors to build an isolation unit for a situation like this?

8-10 volts of AC in an idle condition between ring and ground is not good. In fact, any measurable AC on a line to ground in an idle state will cause hum. It sounds like you have a serious case of imbalance; not something that is your responsibility.

Based upon what you have described, it sounds like the fault is fairly far out, perhaps even halfway between your house and the central office. That is a lot of induced voltage and it doesn't get picked up by a short length of cable. I agree that it probably has nothing to do with several spans of regular drop wire, so it really doesn't require replacement. Just because the drop wire isn't bad doesn't mean that you don't have a problem.

You certainly are within your rights to expect a hum-free line. Whether it is due to an imbalance on your cable pair, a faulty splice or the power company's influence, this is not your problem. I assure you that a call to the PUC will start the wheels in motion.

No, you should not have to do anything as a consumer to filter out this noise.

Ed,
Good to know. I'll give them a few more days and then will file a complaint with the PUC. For what it is worth, there are several people within a few miles of me on the same road with hum on their lines! So I don't think I'm an isolated case, I'm just the squeaky wheel.

I think I'm going to get some numbers/names of others with the issue nearby and go to the PUC.

Do a search using "hum" as a key word. This has been discussed and some insight may be obtained by reading some of the older threads.

The search link is on the right next to "my profile" and "directory".

I think the trick is to find a location where there is no hum---then go backwards or forwards from there. Sometimes that's easier said than done.

A hum can be introduced onto a line by some fairly simple things , so if you're working with people who just don't have a good troubleshooting procedure and don't understand what generally causes a hum---then you can be in a bad position. I tend to look at unbalanced line pairs. It looks like your techs are looking for an electrical source. I think that that may be assuming the cause rather than looking for the cause. Good Luck.

This is common around here. You can put a choke on your line that will probably clean it up. I doubt if you'll be able to get the phone company to do anything. Here\'s a link to an article sandman wrote on AC induction.

Yes, that's what PUC's are for... You’ll be amazed what will happen by just mentioning filing a complaint.

And No, it's not within specs. There is a allowable threshold for noise on line but if what you have is high enough to make it difficult to speak on, it's way out of spec.

I hear what y'all are saying, but there's a location south of here that is bad all the time and is much worse during beet harvest when the remote conveyors are running. The ac induction in some places is so loud you can hardly hear the dial tone. Phone company blames it on the power company and power company blames the beet conveyors. People have been complaining to the PUC for probably close to 30 years with no help. The phone company could put chokes in the cable terminals, they do make them for just that purpose, but they say they aren't going to the expense when it's not their problem. I have put chokes at the customer locations for those who are willing to pay for them, they aren't cheap for the good ones. I do use the ones Sandman mentions in his article. I always tell the customers to complain to the PUC when I get a call on these, they have one tech in that area that always tells them the trouble is inside. :scratch:

Well,
I guess maybe I'll see if the company is willing to put a choke on first... then maybe I'll go to the PUC.

I know it's not really my problem, but are there any plans on-line for building a DIY 1:1 isolation transformer setup? I've put 1:1s INSIDE on the handsets before to isolate a handset from a sound board when we were doing radio recordings, but I'm not sure how I would put a 1:1 on the incoming line so as to avoid shorting out the line and causing the dial-tone to drop.

Just in case anyone is interrested Here\'s a link to where I get the chokes. I haven't delt with them for awhile, but they were very helpful the first time I called.

I had a client where bad electrical ground was creating Hum on all lines and building's Electrician fixed the problem.