Mains plug filter to stop mains interference on Long Wave?

my3cents · 18-06-2018 07:36PM #1

I haven't looked yet and thought I'd ask here if anyone knows of a decent inline mains filter (ideally just a plugin) that will reduce the interference on our mains that gets picked up when listening to BBC Radio 4 on Long Wave.

The interference seems to be due to computers and phone chargers.

Its definitely related to the mains power as in the same location a battery radio performs fine with no interference and a mains powered radio is just so bad you can't listen to it - only occurs on LW (as it would) and not FM so not a crappy radio issue.

humaxf1 · 19-06-2018 09:07AM

Ideally, remove the source of the interference...not always possibly though.

Have whatever is producing the noise plugged in only when required - otherwise unplug them.

Switch mode power supplies are the bane of our lives these days :mad::mad::mad:.

No real experience of filters so unable to suggest one, but I expect a decent one will cost a few quid.

Try a ferrite choke on the power cables to the computers/phone chargers.

my3cents · 19-06-2018 09:14AM

I spent an hour last night looking for a box of ferrite chokes I had :mad: think in a mad clearing out session I must have thrown them out. I'll get a few on Amazon when I next make an order (don't like paying for p&p) and give them a try first.

No chance of switching everything off as there are computers on here night and day. We can even tell if the electric fencer nearby is working by the "tick" on the radio.

I'm also eyeing up the ferrite chokes on the end of a few spare USB cables so might cut them off, cut the plug off the radio thread a choke on with a second pass loop and put the plug back on.

Capt'n Midnight · 24-06-2018 09:30PM

Isolation transformer ?

You could use a car radio to see where the bad spots are.

You can get BBC4 FM on Freesat , and a genuine box does series link too.

my3cents · 24-06-2018 09:48PM

Its only just the Roberts clock radio in the bedroom although I noticed the kitchen radio is getting worse.

I can get BBC4 LW and FM on Freesat but its just not the same somehow and I can't wake up to it. I've several Roberts battery radios and they are all fine in any location in the house so its definitely a mains issue.

I'm going to try ferrite rings on the power leads first then I might try using a bigger ferrite ring and make up something along these lines http://www.m0nwk.co.uk/audio-video/mains-electricity-filter-for-emc-noise-reduction/ .

my3cents · 05-07-2018 12:57PM

Tried the ferrite rings clipped on the power cable (wound around one turn at each end) and no improvement.

In the end because wife was out I went around and switched everything in the house off and finally everything on the fuse board except the one circuit that the radio is connected to (everything else on that ring unplugged) and still the same interference.

So it really looks like I'll be patching the audio from the satellite into the bedroom.

Tabnabs · 05-07-2018 01:22PM

Or get an internet radio.

my3cents · 05-07-2018 01:26PM

Tabnabs wrote: »

Or get an internet radio.

Poor unreliable internet unfortunately.

I did have a plan a while ago to put in a satellite box just for radio and might go ahead with that.

hawthorne · 12-07-2018 07:06PM

my3cents wrote: »

Tried the ferrite rings clipped on the power cable (wound around one turn at each end) and no improvement.

In the end because wife was out I went around and switched everything in the house off and finally everything on the fuse board except the one circuit that the radio is connected to (everything else on that ring unplugged) and still the same interference.

So it really looks like I'll be patching the audio from the satellite into the bedroom.

Switch off this circuit as well and run the radio from a battery. I bet the noise is gone then.

my3cents · 12-07-2018 07:28PM

hawthorne wrote: »

Switch off this circuit as well and run the radio from a battery. I bet the noise is gone then.

I can have all the power running in the house and get BBC Radio 4 on Long Wave on a battery radio in the same spot or anywhere in the house (except close to a computer).

hawthorne · 12-07-2018 11:23PM

my3cents wrote: »

I can have all the power running in the house and get BBC Radio 4 on Long Wave on a battery radio in the same spot or anywhere in the house (except close to a computer).

It must be the power supply inside of your radio so. It is most likely a bad switch mode power supply not suited for it. Get a new radio without an internal power supply and buy an additional linear regulated PSU for it. That will give you noise free listening....until your wife charges her phone....

my3cents · 13-07-2018 08:19AM

hawthorne wrote: »

It must be the power supply inside of your radio so. It is most likely a bad switch mode power supply not suited for it. Get a new radio without an internal power supply and buy an additional linear regulated PSU for it. That will give you noise free listening....until your wife charges her phone....

Its exactly the same on 4 different LW radios :mad:

Used to only happen at certain times of the day (not related to night time ionosphere movement and LW signal propagation) almost as if a farmer started milking it went bad, now its all the time.

hawthorne · 13-07-2018 10:22AM

If the noise is only coming in via the mains power cable you still have the option of running a radio with rechargeable batteries.
In general we are more and more covered by a constantly rising noise floor. Be happy if you still can hear anything. Loads of people in cities have no AM reception at all anymore.
I would still shut down ALL circuits in the house to see if the noise is gone then. You always left the last one with the radio on.
By my experience most strong noise is homemade.
Check with the next door neighbour if he has the same noise problem.

11-03-2019 07:12PM

Op Any luck with eliminating the noise ? and what did you do ?

As suggested , turn off the power to the house and use battery portable radio, if the noise disappears then it's time to start hunting.

Avoid the likes of woodies no name brands or budget LED bulbs which do not comply with regulations in regard to harmful radio frequency interference as with most electronic junk today shipped from China.

Mobile chargers, Laptop chargers, old LCD TV with fluorescent back lights were very bad.

With regard to LED lights I find the best to be Philips bulbs.

Some mobile chargers and LED light bulbs can cause interference as much as 30-40 meters from the house and the mains wiring in the house can act as a giant antenna as some noise can be radiated down the wires all for the sake of a few cents worth of filtering components.

my3cents · 11-03-2019 07:45PM

Well funny you should ask think I got to the bottom of it last Sunday when we had a power cut.

The ESB transformer at the bottom of the garden had a loose connection and when the transformer was replaced most of the interference went.

Still left with some lesser background interference which started a couple of years ago and talking to the lads that replaced the transformer that might have been about the time the voltage changed and went from 20kV to 40kV?

11-03-2019 08:22PM

Nice one, yeah could be.

The electric grid is a mega source of noise for a lot of people myself included.

I've issues with my SDR's picking up a lot of noise sometimes from the power grid which is getting worse so I need to find the pole or poles responsible, the ESB Engineer called my up about it but told him I need more time to try find the source because they're not going to do that but they ill fix an issue if I can pin point it.

When I get my Ham radio license I need to have it sorted because it will effect me with 40 meters of wire for an antenna.

my3cents · 11-03-2019 09:02PM

Try a battery long wave radio and use its directional ferrite antenna to triangulate where the noise is coming from.

Dan Jaman · 26-03-2019 05:57PM

Deleted User wrote: »

Nice one, yeah could be.

The electric grid is a mega source of noise for a lot of people myself included.

I've issues with my SDR's picking up a lot of noise sometimes from the power grid which is getting worse so I need to find the pole or poles responsible, the ESB Engineer called my up about it but told him I need more time to try find the source because they're not going to do that but they ill fix an issue if I can pin point it.

When I get my Ham radio license I need to have it sorted because it will effect me with 40 meters of wire for an antenna.

I had a really annoying buzzing, crackling interference that covered the whole HF band and more. I was in a cottage that was at the end of a 230V line to the nearest pole-pig, about half a mile away. By walking the length of the line with a tranny I identified the offending insulator and called the ESB. Fairness to them, they were out and fixed it within a couple of days.
That cottage was marvellously RF quiet, out in the middle of nowhere and I could pick up the world.
Well, except when the farmer down the road (at the pole-pig) started welding, and when he fired up his milking parlour, the voltage dipped to about 200 or less.

26-03-2019 06:45PM

Yeah , I need to identify the offending pole that is interfering with my SDR's too, they did call me up to come out and look at it but I said to wait until I can identify the pole so as not to be wasting time.

Malmsteen · 25-04-2019 09:34AM

my3cents wrote: »

Try a battery long wave radio and use its directional ferrite antenna to triangulate where the noise is coming from.

Did this recently with strange noise on Am and discovered the next door neighbour had a pre-paid meter installed :-(

25-04-2019 02:58PM

Malmsteen wrote: »

Did this recently with strange noise on Am and discovered the next door neighbour had a pre-paid meter installed :-(

Yeah could very well be that , could be many things really and a combination.

Mains plug filter to stop mains interference on Long Wave?

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