Dsl And Electric Power Poles

[sbk]

A few months ago the local electric office, in all their wisdom, put a very large transformer right next to our phone line. That night, when everyone turned on their lights and power surged through the transformer, we lost our DSL signal. And we have lost it every night since. Already checked with the ISP, its not them. Looked on the internet and found that electrical interference can cause interrruption to the DSL signal.

We have been waiting since FEBRUARY for the lineman from the mainland to come and move our line. Don't know when that is going to happen. So, short of blowing up the transformer does anyone have any suggestions? Is there some gadget I can buy that can help overcome that interference or am I just stuck with painfully slow dial up every night until the phone company (TT&T) deigns to send their guys out to move it?

[sting01]

A few months ago the local electric office, in all their wisdom, put a very large transformer right next to our phone line. That night, when everyone turned on their lights and power surged through the transformer, we lost our DSL signal. And we have lost it every night since. Already checked with the ISP, its not them. Looked on the internet and found that electrical interference can cause interrruption to the DSL signal.

We have been waiting since FEBRUARY for the lineman from the mainland to come and move our line. Don't know when that is going to happen. So, short of blowing up the transformer does anyone have any suggestions? Is there some gadget I can buy that can help overcome that interference or am I just stuck with painfully slow dial up every night until the phone company (TT&T) deigns to send their guys out to move it?

Basically, a transfo will create a huge magnetic field, the actual technology for what I ahve seen here using the Neutral to phase (the transfo create the neutral as the blank point of the 3 phases (sorry I do not have the english level to explain better). The other technic is to that the Neutral to Ground, mean Neutral is created by the transfo with the ground. Your transfo is in fact what we call 'unfixed' (decalle in french), mean the neutral is not from the blank point but just before or after, so there is a magnetic field. Very hard to fix mostly.

My suggestion (but it's just that), would be to protect your line, by using metal cylinder like for plumberie. Also, there is a trick, if your line is perpendiculaire to the electric line, and if there is a magnetic field, then the magnetic field will intefere with your phone line (DSL line). Another trick would be to put your phone line under the electric transformator, and running along the electric cable. So it will be less interference.

Last trick, this one used in Sophia Antipolis in 1992 in the IBM Building (French Riviera), is the following :

your electric cable is constituated by 2 small cables, you take only one of them, pug it to a lamp (calling it because my bad english ENTRY A), ENTRY B of the lamp will be relied to the ground, or for exemple your plumberie .... Electricty is a lazy person, so rather to go to your modem / computer, it will go to your lamp, and then to the ground. As the electricity created by the magnetic field does not have the same frequency as the DSL signal, this one should be cleaned and go to the computer.

Hope it help

[stumonster]

how much line are we talking - wrap it in alfoil and connect a wire to the foil at one end to a piece of steel driven into the ground .

[sbk]

OK, sorry I am not a technical person here at all. Are you suggesting we ground the electric line before it comes to our house? or something else entirely and I am just confused?

It would be difficult to protect the line as it goes by the transformer as we don't know which one is ours, there are several phone lines there (hence why we have to wait for the mainland lineman to come, the local guy doesn't know which line is ours either and has no equipment to find out ). So, our best option would be something we could do here at our house.

[stumonster]

wrap them all as they go past the transformer , and the wire to ground can just be a skinny piece.

instrumentation cables have a foil wrap ouside beneath the outside sheath to which you connect one end to a instrument ground - we call it a drain , as it is used to intecept and EMF that might interfere with the signal.

this is just a dodgy brothers idea , it won't look pretty but its cheap and it might well solve your problem until the telecoms boys sort out the routing of the lines for you.

[monty]

Main problem of ADSL in Thailand, all those unshielded phonelines parallel with the power lines. ADSL unfortunately does not stand noise very good, reason why TT&T will only hook you up if you're less then 3km away from their station. In the west theý at least come check your line up to 8 or more km's away to see if you get acceptable signal...

Since you're pretty much sure that the transformer is causing the noise, all the above advice has a very good chance of helping...

Try to get a local handyman to climb up to the phone cables and shield them all with metal foil, which then has to be grounded with just a small wire...

[sting01]

Main problem of ADSL in Thailand, all those unshielded phonelines parallel with the power lines. ADSL unfortunately does not stand noise very good, reason why TT&T will only hook you up if you're less then 3km away from their station. In the west theý at least come check your line up to 8 or more km's away to see if you get acceptable signal...

Since you're pretty much sure that the transformer is causing the noise, all the above advice has a very good chance of helping...

Try to get a local handyman to climb up to the phone cables and shield them all with metal foil, which then has to be grounded with just a small wire...

Monty, one question, may I? I stopped to touch electricity since I am in thailand, but I am quite sure parralel lines will do okie, the problem if I recall well is when they are perpendicular (intersection at 90 degres).

I am quite sure we used to place both cable in parallel (using Colson if you know that brand to make them really paralels on long distance).

Anyway not that important, if I justto know if I am going old and insane, lol

[monty]

To long ago as well for me!

But anyway, there's way to much noise generated at these transformers etc...

ADSL signal is just so sensitive to that stuff...

They even do not use twisted wire to reduce interference here...

Edited April 9, 2006 by monty

[sting01]

To long ago as well for me!

But anyway, there's way to much noise generated at these transformers etc...

ADSL signal is just so sensitive to that stuff...

They even do not use twisted wire to reduce interference here...

I agree, and my question was innocent, believe me, sometimes memory goes wrong and I just would like to know.

Anyway, here no tranfo problem, but they used small cable of 10 cm to make one long as 60 cm, so low signal ... that is thailand, if you smile and ask nicely they will do.

[monty]

Sometimes you can get lucky as well!

I'm over 7km away from the telephone exchange but still have acceptable signal (for 256/128 anyway).

I'm lucky because I'm close to the junctionbox where the big main cable(maybe 100 twisted pairs) arrives. From there it's only a short distance on the standard straight two wire cable to my house.

These big main cables pick up hardly any noise since they are shielded, and all those twisted pairs are also twisted together. Very hard to pick up any noise...

Also very little loss since the main cables are joined and then completely sealed, so no humidity to mess up connections...

Other subscribers have less luck and are a few kilometers away from the main cable, there where you see big bunches of those two stranded cables hung together in the powerpoles (like SBK's line).

[lom]

sbk, are you getting the ADSL signal back shortly after or does it take until everyone turns off their light in the night ?

I ask because power surges could reset your ADSL-modem in which case you need a voltage stabilizer or ups.

[sbk]

sbk, are you getting the ADSL signal back shortly after or does it take until everyone turns off their light in the night ?

I ask because power surges could reset your ADSL-modem in which case you need a voltage stabilizer or ups.

The modem is plugged into the UPS So, no go there I am afraid. Also, it is out ALL NIGHT LONG!

sorry for the shouting but it has been a few months of waiting

Showed the thread to my husband, he is going to call up the local guy (the one who can't move the line!) and see if he can at least get it shielded and grounded as you guys have suggested.

thanks for the info, I'll let you know how it goes

[tjo o tjim]

It would seem odd to me that the transformer itself would cause a problem. While it does create a significant magnetic field, the way EGAT does transformers is constant throughout Thailand, so I can't imagine TOT just having a problem with your DLS line and not everyone else.

Electric fields are perpendicular to high voltage lines; magnetic fields are parallel to low voltage power lines. Simple shielding would protect you from the electric fields, so I can't imagine that this would cause the problem. Magnetic fields would be caused by your telephone line running parallel to the power lines, but that should only be a problem in the voice frequencies - you might hear a low hum when you are on the phone.

Are you close to a generator? That would be a more likely cause for interference. Short of that, is the time consistent when you lose DSL service at night? Same on weekdays/weekends? Do you know when it comes back on? Do you have any neighbors that have the same problem? Do you experience the problem every day, or does it just seem like it? During the daytime does everything work smoothly? Do you know how far (along the road) you are to the central office? Did you get your phone line recently, or have you had it for ages?

I would be surprised if the transformer is the problem. There could be another culprit, but it is odd that the transformer coincided with the start of your problem. Was the trasnformer to serve a new building/business? Do you know what they do, what their hours are?

And, one last dig - the shielded vs unshielded is an old debate. The americans won, and now the world is mostly unshielded. Shields have their own problems - do you ground both ends? if not, which one? should you ground it in the middle as well... Since Thailand is an unshielded country, you are better off keeping away from them; you are more likely to get a good shock from your computer than solve a problem here.

Edited April 9, 2006 by tjo o tjim

[stumonster]

only ground the foil shield at one end - otherwise you will create a loop

and don't forget to save enough alfoil to make a fetching bonnet ...

[sbk]

Are you close to a generator? No

Short of that, is the time consistent when you lose DSL service at night? Same on weekdays/weekends? Every day at around 6:30. Time varies about 10 minutes. When it is dark and cloudy then it goes off earlier.

Do you know when it comes back on? Sometime early morning, my husband tried it at 4 am once and it was still off.

Do you have any neighbors that have the same problem? NObody else has DSL

Do you experience the problem every day, or does it just seem like it? Every day

During the daytime does everything work smoothly? Great unless it rains

Do you know how far (along the road) you are to the central office? quite far about 7k

Did you get your phone line recently, or have you had it for ages? We have had the phone for about 3 years. Dsl about 8 months

There could be another culprit, but it is odd that the transformer coincided with the start of your problem. Was the trasnformer to serve a new building/business? Do you know what they do, what their hours are? Transformer was put in for Hadrin. They put the transformer in and that night out went our DSL. The transformer is literally about 1m away from the phone line and the linemen from the mainland told my husband they have had this problem before, elsewhere

[Tywais]

I realize this is an obvious question, but do you have the splitter/filter for ADSL installed? Perhaps it's faulty if you do have it or connected incorrectly.

[sbk]

Yup. changed it once already. If the splitter were faulty why would it only go out at night?

[Crossy]

I doubt that it is the transformer itself that is directly causing the problem, modern transformers are very good at keeping the magnetic field inside (escaping field costs money).

BUT

I suspect that your phone line runs parallel to the supply to the new transformer for some distance and the additional current in this line is inducing nasties in your phone line. For this reason I suspect that just adding screening near the tranformer won't have the desired effect

A couple of thoughts:-

Does the DSL come back if you take the phone off hook (and leave it off)? Any nasty buzzing in the phone handset?

OR

Try this, get a length of wire and ground one end, do NOT use the electrical ground, stick something metal in the ground and connect the wire to it, it does not need to be a very good ground. Now, take the phone socket off the wall, you will see two wires. With your phone off hook, touch your ground to each wire in turn. Touching one wire will stop the phone working, connect the ground to the OTHER wire. Make sure the phone and DSL still work. WAIT. Does the DSL still go off? No--problem solved. Yes -- take the phone off hook, does it come back now?

If either of these ideas gets you going, all well and good but it's not the ideal solution (interesting to know if it makes any difference though). What you are doing is providing a fairly low resistance path for what is known as 'common-mode' noise which is probably swamping the front end of your modem / router. If it does work let me know and we can come up with a more elegant solution.

Of course, I could be barking up totally the wrong tree and a couple of feet of Al foil wil solve your woes.

[Tywais]

Does the DSL come back if you take the phone off hook (and leave it off)? Any nasty buzzing in the phone handset?

This is the best way (Crossy's statement) to determine if the power lines are at fault. If the interference (50Hz) was strong enough to be heard in the phone then it could (potentially) interfere. I doubt it though because the ADSL filter traps the lower voice frequency and separates the higher frequency (DSL) signals. If it is really loud then harmonics from the 50Hz could cause interference. Call someone and see if there is a loud buzzing in the phone.

As for nightime, there would be more people home using air and other appliances causing a larger current flow through the line and therefore more induction into the line, if it is the A/C line.

Edited April 10, 2006 by tywais

[tjo o tjim]

SBK -

A last-ditch effort would be to install an optical line isolator for your telephone line. I know they are fairly expensive, and have no idea where you would find them in Thailand. The site above is in the US and quotes $320 for the device. (It was just the first Google hit.)

These are primarily for lightning isolation, so you might be able to find a device that is intended more for electrical isolation.

I think you are going to have a challenge with just moving the phone line away from the transformer; it should be the cables off the transformer that would cause a problem, not the transformer itself.

I would be a little nervous here about grounding one end of your telephone line - grounds are funny here and you could actually fry something. If you do ground the phone line, do it outside of the house.

[tjo o tjim]

One other idea...

If you wanted to try and make your own transformer for sh!ts and giggles, take a 25' telephone cord, cut off the ends, and wrap it tightly around a piece of steel (maybe a 1cm square section 100mm long). Connect each end of one wire to the each of the incoming wires, and do the same to the modem line with the other wire. Not pretty, but that will eliminate any common-mode noise. One of the wires on the modem side should be grounded as Crossy instructs. No guarantees, but it is a cheaper solution.