Reducing noise

[willemvdm]

I have a cordless phone. The last month or so the cordless phone became very noisy. I found that moving the power line around improved the situation, but did not clear the noise completely. The noise however don't seem to affect ADSL.

I have a little round filter thing, don't know what it is called that I took of from another cable that I no longer needed and I put it on the power line of the cordless and the noise completely disappeared. In fact the cordless never beer as clear as it is now, just as clear as the ordinary telkom phone.

So early this morning I got no throughput on my line. I checked my SNR and found it to be 3db. A few hours later now and it is back to normal, 15db. I'm far from the exchange. But my question is, would such a filter thingy improve the SNR on my line and where would I need to put it, on the line itself, on the power cable of the router and where would I get one? A PC shop I assume. What do I ask for?

The device I'm talking about is a cylinder shape with 2 magnets inside that you loop the wire through. What exactly does this do to the wire. Just seem like a magical, useless thing that don't even make direct contact to the wire, yet it does make a huge difference.

 

[gwainw]

These "cylinders" are called ferrite chokes. Their goal in life is to reduce EMI (electromagnetic interference) and RFI (radio-frequency interference).

 

[zeely]

that magnet thing reduces electrical interference. So if you run your telephone line next to a 240v AC power line, it wont induce current into the data line

 

[willemvdm]

So do you think it would be worth it to get one and place it on the line or do I put it on the power lines?. It doesn't run next to power lines, but there are a bundle of wires laying around at the end point where the router are. Are there anyone here that use these ferrite chokes on their lines? Does it help?

 

[JerryMungo]

So do you think it would be worth it to get one and place it on the line or do I put it on the power lines?. It doesn't run next to power lines, but there are a bundle of wires laying around at the end point where the router are. Are there anyone here that use these ferrite chokes on their lines? Does it help?

It won't hurt to put it on the phone side of the telephone cable, but the way to truly see if it's EMF you're dealing with is to get an extension cord to plug your cordless phone in with (from another room), switch your plugs off completely in the house - all except the circuit that you have the extension cord plugged into (flip the circuit breaker). Check if you still have the noise. If not, it could be something in the vicinity like a printer with 'noisy' power supply etc... even in the next room.

If you do, it could be coming from the phone's power supply - if it's external, move it and see how that affects it, if it's internal, it could have a ground fault (but you won't really be able to confirm properly that this is the issue since you can't move it around).

Try another phone altogether is the best bet (corded or cordless).

 

[willemvdm]

Neither the cordless phone nor the normal phone has any effect on SNR. I've tested with both unplugged and powered off. What I'm wondering is since the ferrite choke had such a huge effect on the cordless phone itself, if it won't improve SNR by putting one on the tellephone line itself before going into the router or the routers power line. Even when the cordless were noisy, it didn't seem to effect ADSL. I suppose the micro filter did its job.

 

[InTheCube]

What speed line do you have, how many extensions on the line, and do all the extensions have filters?

Also what brand of cordless phone do you have?