New interference on MW

[PaulR]

I switched on my AM bedside radio last night to listen to R4 via Logitech Sqeezebox ans SStran transmitter and there was a noise something like motorboating. A sort of phut - phut noise at 5Hz or so. It sounded something like the ignition of an idling car, even down to the odd misfire but a bit "softer".

I changed my internet supplier and the new service started yesterday so I immediately suspected the new equipment, but I switched that off and the noise continued. It is still there now and is apparent on all the sets I have tried.

Can anyone suggest what it might be? It is annoying as I have just managed to eliminate an annoying modulation hum.

[G6Tanuki]

Switching-off _your_ gear doesn't stop the ISP's gear in the street-cabinet sending its "hello, can you hear me?" signals down the wire.

Is the noise you can hear tunable (does it appear at intervals when you tune across the band) or is it constant?

[PaulR]

It is superimposed on the sstran signal in a similar way to modulation hum. It is apparent on other signals but not as strong

[paulsherwin]

It's going to be mains borne interference of some sort. Unfortunately it's always a pig to sort out. It may be originating streets away.

Can you hear the interference on a portable radio held close to your mains wiring? Can you hear it on the street from your house phase or from the other two phases?

[PaulR]

I have just walked around with a portable radio and the popping faded as the signal from the sstran did. Investigating again the signal is only superimposed on the transmitter's. I think that I was misled by some sort of image coming through at another point on the scale.

I tried unplugging the internet from the box at the BT socket and that made no difference.

The transmitter is near to the squeezebox and if I move it nearer then the popping gets louder. The rotation of the transmitter relative to the squeezebox also affects the interference. I therefore tried unplugging the squeezebox and it stopped.

It therefore seems to be something being transmitted from the squeezebox itself rather than the mains. The fact that it only started with the new internet supplier seems significant but I cannot reconcile how. It continued last night when I switched the internet box off.

I will try physically separating the transmitter from the squeezebox to see whether that helps, but it is a strange situation. I have used the current set up for years.

[Gabe001]

If you changed ISP they may be trying to optimise your phone line (which takes a week or so), so I wonder if that could be an issue. Have you installed any power line internet extenders on your mains? Have you tried setting your mobile up as a WiFi hotspot and getting the squeezebox to connect to that?

[PaulR]

Hmm, the phone line outside runs on the other side of the wall from the squeezebox. I wonder if it is picking something up from that.

I am not sure how to do the phone idea. Unlike many people these days I am not really into mobiles.

I will try moving the squeezebox from its current location near the phone line to investigate whether it is picking something up. It is also connected to the amp in the room and there is no interference on that.

[Gabe001]

Try a different power source for the sqeezbox in case it's a fault with the transformer/power supply.

To set up a hotspot put your phone on mobile data (WiFi off) then go to settings -> wireless and networks -> tethering and mobile hotspot

This will essentially create a WiFi network you squeezebox can connect to, which in independent from your ISP

Good luck
Gabriel

[PaulR]

Thanks Gabriel.

Even hanging the transmitter over the front of the shelf helps so I will move it further. It seems to be some sort of direct interference between the two which just started out of the blue. Maybe the squeezebox is picking something up from the phone lines which are only a cavity wall's distance away. I can't get past thinking about the coincidence of the new ISP provider though.

[paulsherwin]

Believe it or not, this is actually good news. You know what device is the cause of the interference, which is more than half the battle.

Changing ISP is very unlikely to be a factor unless they have supplied a faulty router, and even then it's only a remote possibility. Similarly interference from the phone line is unlikely if it wasn't there before.

As others have said, try powering the Squeezebox from another power source. If you have a scope, you can try scoping the PSU output. A Squeezebox is just a small computer, and will put out some digital hash while running. Try wrapping it temporarily in kitchen foil.

[PaulR]

Thanks Paul

I will try powering it from another source. if that doesn't help I can always move it to another part of the hi-fi cabinet. It makes the perfect combination with the transmitter as the remote works over the internet and I can change stations from whichever room the vintage radio I am using is kept.

[Gabe001]

Originally Posted by PaulR

Thanks Gabriel.

Even hanging the transmitter over the front of the shelf helps so I will move it further. It seems to be some sort of direct interference between the two which just started out of the blue. Maybe the squeezebox is picking something up from the phone lines which are only a cavity wall's distance away. I can't get past thinking about the coincidence of the new ISP provider though.

It could be IMO, probably the new ISP is running DLM (dynamic line management) to optimise the new connection. This should resolve itself in about 7-10 days
Maybe your new line filter (if you need one) is not up to scratch (try using another one)
Maybe the signal to noise ratio has been set incorrectly for your line. Usually this is accompanied by slow internet performance. How does the landline sound, is it noisier than before? Is your internet speed as good as expected?

I think if the issue is fixed by moving the box away from your phone line that's great, but worth trying again in the original place next week and see if the issue resolved itself, and if you landline is or remains noisy may be worth calling them and asking them to check your line for signal/noise. They can run diagnostics remotely whist you are on the phone.

Hope this helps, but it seems like you've got a workaround anyway so not all is lost

Gabriel

[PaulR]

The internet speed is very good - faster than we are paying for, but the BT cabinet is very close so we are only relying on copper wire for less than 100 yards. This is all underground due to old Southport bye laws about telegraph poles but I don't know whether that makes any difference.

The line was noisy, but I suspected my rather circuitous wiring here in the house so I just connected one modern phone to the main box whilst disconnecting the rest. I haven't had a long conversation about old radios and cars with my friend yet to give it a proper test!

It does seem to be a great coincidence that it started as soon as the new ISP took over. I might leave the transmitter dangling over the shelf for a week or so then put it back to see whether the noise has ceased. Watch this space!!

Thank you

[paulsherwin]

Have you switched from ADSL to 'fibre' (FTTC)? The line protocols used for FTTC have a different characteristic to ADSL, particularly for the 76Mb service, so it's just possible that the interference profile has changed, but it's unlikely.

[PsychMan]

Location is a big one. I've had a pantry transmitter with noise imposed on it in one location regardless of what I did, I just had to move it somewhere else, I could never explain why. The proximity of cabling of any kind near the transmitter and antenna can have an effect, so new cabling installed to the house could have changed the operating conditions there.

If you cannot make it work inside your home, consider mounting it outside. I have mine outside mounted on a wall in a really useful box along with the loading coil I built. The antenna is mounted to the wall and the ground is a ground rod near the transmitter. Audio and power are sent to the box via cat5 . This may seem like overkill, but this has been the only configuration that has provided me a good signal throughout my property. In particular I think using a separate earth to the mains earth helped a lot.

I had many problems before this, including a switch mode power supply which previously had caused no issues, and then one day started to create tons of noise on my signal. Enough that I could detect it radiating from my property nearly 2 doors away with a portable radio!!

[PaulR]

Still on ADSL. I changed because the old supplier could not make the connection work for more than a day or two without dropping out (no good for the squeezebox) and the noise on the phone line was bad.

[paulsherwin]

Noise on the phone line when using a POTS phone is almost always down to line faults like bad junctions or water ingress. That won't help your ADSL of course. Changing ISP shouldn't have made any difference unless Openreach have fixed the underlying fault in the interim.

I think your interference issue is a separate problem though.

[PaulR]

The BT engineer who came out under lockdown and was very impressed that I could give him a "quiet line" number he did not know said he had tested the line from the cabinet and he thought the fault must be in the exchange. I had been told that my previous supplier used their own equipment in the exchange so I thought that changing might help

[paulsherwin]

Some ISPs do use their own DSLAMs in the exchange for ADSL rather than just paying BT. This is called Local Loop Unbundling and is supposed to increase competition between ISPs. It isn't practical for FTTC so is falling by the wayside as people switch to FTTC subscriptions.

It shouldn't make any difference to line quality, though it's possible there may be a wiring fault in the exchange because of a simple wireman's error.

[PaulR]

When we first went onto the previous provider there was a problem with the phone not ringing. Eventually it was traced to a "card?" in the exchange. The BT engineer said that the supplier used their own equipment in a locked cabinet in the exchange. Eventually they got it unlocked and the problem was corrected by using another card.

When the noisy line started and the line between the cabinet and the house was cleared I wondered whether the equipment in the exchange was at fault. There was no way of explaining all that to the call handler in the call centre and the message being passed on so I thought that changing supplier might help. At least they would have to use different equipment in the exchange.