Sunspot activity is currently low. In any event, it really doesn't produce a high enough wide band interference to make more than a marginal difference to ADSL unless it's a very long line with poor balance. Wide band interference is usually caused by something a lot more powerful locally generated.

Of course if the Earth was hit full on by a coronal mass ejection, then that would be an entirely different thing.

Radio reception tends to be a lot more sensitive simply because antennas are designed to pluck electromagnetic energy out of the environment. In general, a phone line is designed not to pick up interference, albeit to a fairly basic standard which can be heavily compromised with poor wiring.

http://www.solarham.net/

If you were suffering so badly from sunspots it would be happening to thousands, and the forums would be full of similar problems.

I think it is fair to say if Sunspots are to the level of affecting of affecting twisted pair networks that there will have been many AM radio stations knocked off the air too.

In terms of finding it, this is why AM radios with a directional ferrite core may seem silly cheap, but as a basic RDF will show if source is local or widespread, i.e. sunspot activity is not going to go up or down when moving just a few feet.

Are we solving a theoretical problem or is there actually a noise issue that someone is having trouble with.

In reply to a post by RobertoS:

If you were suffering so badly from sunspots it would be happening to thousands, and the forums would be full of similar problems.

But they are! People are noticing download speeds falling but nobody knows why. Anything relying on bouncing off the ionosphere would be hit by sunspots but the frequencies that ADSL use are quite low being only a few Mhz with very low energy. I believe ADSL uses Frequency Modulation so pulse or SHINE effects are not as bad as repetitive REIN noise. Can REIN be cause by Coronal Mass Ejections that are directed our way.

I remember the days when AM radios could be affected by noise making the channel hard to listen to. Then came black & white tellies. If somebody switched on an electric drill next door the screen would fill with snow making the picture unwatchable. You could experience the effects and do something about it. CME could play havoc with both especially when a barometric high was over us.

The effects with ADSL are invisible and the only effect to be seen is changes in download speed that people attribute to Openreach or exchange problems. Just how prevalent is REIN noise anyway? TV detector vans should be able to see this noise but its frequency may be too low. If an area is plagued by REIN noise Openreach have only limited resources so the inevitable result is they duck the issue and any Openreach operator wishing to raise a case is going to have a hard time.

The ISP is the first to feel the brunt of this. They buy a product from BT Wholesale that is degrading but it may not be an Openreach or BT problem. Who can say anyway that the noise is not coming from the exchange itself because somebody installed a dodgy bit of kit.

In reply to a post by Zarjaz:

Have they visiting engineers raised a REIN task ?

Ok, so we get the instrumentation and attach it to the master socket.

What equipment ? Are you sure the source isn't in your property ? If your property is fed by overhead D-side cables to the DP then any noise picked up on a radio for instance can be radiating a long way from the source.

The Openreach engineer will ask you to turn off the main electrical supply to your property that way they can tell if its a problem with your equipment.

"People are noticing download speeds falling but nobody knows why"

Care to share some examples.

This thread is getting odd, you seem to be asking questions that you know the answer to.

SFI engineers from Openreach have in the past found interference sources that may be 100m or more away from a property, i.e. they are able to identify sources given the time to investigate.

In reply to a post by MrSaffron:

This thread is getting odd, you seem to be asking questions that you know the answer to.

Not so, the answer is I simply don't know and have no way of finding out. CE accreditation covers RF noise but I don't know whether frequencies that affect ADSL tones are covered. Most equipment has moved up the spectrum in terms of RF frequencies so REIN affects may not be apparent to users of everyday equipment.

Looking at frequencies

https://en.wikipedia.org/wiki/Band_of_frequencies

The gap between low and medium frequencies is where ADSL sits. All PSUs these days are switched mode using square waves which generate wide band noise. I might post on a radio ham forum to see what they say and get back to you on this.

Back in the 1950s, I received a report from the RAND Corporation in the USA that it had been asked to track down the source of intermittent interference occurring to US Coastguard communications in California.

The source was eventually tracked down to an HF Oven, conventionally shielded etc and apparently working effectively in its own location, New York City, about 2,500 Miles (around 4,000 Kilometres) away!

http://www.rand.org/about.html

Unlikely in this specific case; but a salutary warning of how far interference can cause problems.

Yes is the answer.

It can be worse for VDSL (FTTC) lines too.

Many of the worlds Shortwave radio stations transmit Megawatts into the ether, likewise amateur and commercial radio comms systems proliferate the band.

ADSL receives operate at the lower end of the spectrum, VDSL basically lives in the majority of the Shortwave band.

A common misconception , is the only reason ADSL/VDSL services go slow in the evenings is due to contention and load. This is part of it but another issue is the propagation behaviour of shortwave / medium wave radio signals around that time of day.

Those primarily affected will have overhead lines as part or most of their run to their house. These act as huge aerial arrays.

Although the phone line is meant to be balanced and therefore strong common mode (on both wires) signals are meant to cancel out at the modem, in real life the input stages of the ADSL/VDSL receiver saturates if it gains volts of Strong RF interference.

Add to this directly wiping out the data carriers if the interferer is on that frequency and intermodulation / imbalance issues that increase as a line gets longer and you have a very hostile environment .

VDSL will suffer this to a greater extent on standard overhead lines due the the much wider bandwidth it covers , especially if more than a few hundred metres out from the cab.

TANSTAAFL rule always applies with relation to speed/distance/interference on copper twisted pair.

Their Ain't No Such Thing As A Free Lunch

Fortunately higher radio bands in the GHz arena are unaffected by sunspots but do sometimes experience some interesting long distance propagation effects including ducting from different temperature layers of air, causing refraction.