HF interference on my ring main?

Discussion in 'Interference Problems' started by M6VWM, Apr 1, 2018.

  1. Ken G3SDW

    Ken G3SDW Moderator

    Matt i posted my last post just before i turned in last night and one thing kept going throng my mind and that is what you said, ie This suggests its either the mains itself, or the PSU (Diamond switching).

    When you turn off your mains supply then surly you use battery power to supply your rig?

    SMPS`s do sometimes cause RFI but if the mains is totally off how can they.

    Can you explain why you mentioned this.

    If the RFI is coming up the mains supply then taking out the antenna then it will still be there, if when the antenna is back in nad the RFI returns then it is being picked up by the antenna.

    You mentioned early this year that you were having your mains supply checked out by a family member, is he a qualified electrician,
    NICEIC Approved or someone who is doing you a favour.

    He should be able to check to see if there is something still connected to your mains supply when everything else seems to be disconnected.

    I will say again a ring main with nothing connected to it cannot to cause RFI, other than if any new electronic meter has been supplied in recent times, which is a very long shot.
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  2. Ken G3SDW

    Ken G3SDW Moderator

    Matt been doing some investigation and i need to know what sort of electricity meter you have, as you say the house was built in 86 so assume that after 30 years plus that it has been replaced, no doubt before you moved there, this is a very long shot.
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  3. Ken G3SDW

    Ken G3SDW Moderator

    Matt tell me more about your Hive system??
  4. M6VWM

    M6VWM Member

    Hi Ken,

    Yes my brother is a fully qualified electrician I am waiting for him to come back to change my fuse board for a RCD and do a full diagnostic. He found a bad earth in a couple of sockets which were replaced and resolved that, I had a few surge protectors blow but that is now sorted. I also had a decorator in and I checked the light switches he had removed whilst decorating and found those incorrectly wired up and corrected that too. My brother feels there is still something not quite right with the earth and he has said he will do a thorough test when he visits. Still waiting sadly.

    I did wonder about the hive system, I have tried isolating the boiler power at supply and unplugging all the powered devices, noise is there. This would leave the door sensors (battery powered) and thermostat (also battery), removing batteries didnt seem to make a difference. Girlfriend also recently turned on a water pump in the garden, turned that off too.

    The electricity meter is the original one it has never been changed and I must admit I hadn't even considered that. Let me go check what model it is.

    I have also put up new antenna at the end of the garden and I know the neighbour behind my house on another street tends to have compressors, extractors and all sorts of things in his garage for his classic cars and spray booth. I don't suspect him however as the weird background noise on the 2m band is for an antenna thats close to my house not his.
  5. M6VWM

    M6VWM Member

    I also did a thorough search of the attic for a tv amplifier or similar but couldnt find anything. Also isolated shower power supply and disconnected my bathroom shaver point. TUrned off fridge and all appliances too again no difference. It's very odd.
  6. Ken G3SDW

    Ken G3SDW Moderator

    Hi Matt, the simple fact is that with your mains off then the problem is not there, that can only mean it is being generated by something in your own home, there is no other way.
    Bad connections will not give you noise problem, well steady ones as arching will be more like a crackle.

    Let us know what your brother finds when he changes your electrical system, and if you could take a picture of your meter, with details, as we at the EMCC are discussing all possibilities of what it could and what can be done.
  7. M6VWM

    M6VWM Member

    Here is the meter, the white box seems to suggest 2003, I lived here from 2001 but I don't recall them changing it.

    Attached Files:

  8. Ken G3SDW

    Ken G3SDW Moderator

    Thanks mate i will pass it on the the EMCC
  9. M6VWM

    M6VWM Member

    Well some more info today and sadly can now confirm the noise is not just from inside my house. Running on battery today with no power to entire house still seeing s7 so it seems interference is external. Turning off the fuse box makes no difference it used to drop it to 3 or 4 but now stays at s7. Perhaps it was a fluke before or this is just hiding any change in local RF

    I am now suspecting the garage near to my pole which is a chap who lives on the road behind. He uses his garage as a spray booth so you sometimes hear compressors and fans going could it be that?. He has always been a bit rude sadly when I tried to say hello in the past, so I’m not hopeful of him being willing to test with me.

    Such is life never mind. Thanks for all your help and time. I think I’ll wait until my fuse box is changed and have another look after. I may just have to accept my house isn’t in an area conduscive to radio.
  10. Ken G3SDW

    Ken G3SDW Moderator

    The situation you have now is becoming most common, multiple sources of RFI

    The guy in his shed at the rear is not the main one but just another one, your main concern is what ever is causing the big problem in your house.

    Hopefully that will be rectified once your house wiring and new consumer unit is fitted.

    The assuming that it is still there then you can concentrate on the other one, in the mean time i will close the case and open a new one assuming that you still have problems in the future.

    Good luck mate.
  11. M6VWM

    M6VWM Member

    I realise the case is currently closed but I thought I would share some observations...

    The new consumer unit didnt seem to make any difference, and turning off the power in the house no longer eliminated the noise as we discussed.
    The noise floor actually rose to S9 through August and into September. I went on holiday for two weeks and it seemed to be back to S7 over the weekend on 20m but there a small part of the band where it is s8.

    Still interesting but still can't really get on the air without finding a remote field.
  12. Ken G3SDW

    Ken G3SDW Moderator

    Are you saying that when the mains is turned off your RFI is still there
    Ken G3SDW
  13. M6VWM

    M6VWM Member

    Yes, I re-read the thread and hadn't realised I hadnt updated a few developments. We got the RFI down to S3 by replacing a few sockets that failed testing, combination of old and a few that a decorator had not connected back up correctly when they did some work for us .

    I had a week or so with the lowest noise I'd ever seen S2 to S3 and some great contacts, however end of August I turned the radio on one day to see the s7 even with my fuse board shut off and no power to the house entirely. So sadly the RFI no longer vanishes and seems to be external to my house.

    It was upto s9 last week but is back down to s7 with a spot thats s8.
  14. Ken G3SDW

    Ken G3SDW Moderator

    Sad to say that until you locate it externally then it will not go away.

    Ask a local club if they can assist you, there is no quick fix and no crystal ball but there is for sure something local to you causing your problem.

    Last edited: Sep 25, 2018
  15. M6VWM

    M6VWM Member

    Thanks Ken appreciate your continued support.

    I’ve managed to get hold of a detector and as is often the case now I have it the noise has gone haha. Back to s3 and below on 20m. Completely clear on 40m no noise floor.

    I’ll hold onto it and hopefully find the source very soon.

    You have to laugh but it was nice to hear a signal that was clear as day despite being s1.

    Gives me hope it’s fixable and traceable.
  16. Ken G3SDW

    Ken G3SDW Moderator

    The odd thing about the noise you are getting is that it is so variable to a point that today it is off completely.

    Maybe and it does happen is that what ever it is has been faulty for a While and now has packed up completely, lets us hope so.

    It cannot be coming from your ring main but i feel that it maybe very close like next door, think you said that you have checked with them and i am sure that they would not have any idea that they are causing a problem but if it is something that has packed up then they would know about that, maybe worth a chat if it continues to stay off, again lets hope so.

    Fingers crossed.
  17. gm3sek

    gm3sek New Member

    Just a thought: if you are in a row of houses fed from a 3-phase line, check the other houses nearby that are on the same phase as yourself. For mains-borne interference, these may actually be your "nearest" neighbours.

    Normally those would be the 3rd, 6th etc houses on either side along the row - but from experience, that pattern can't always be guaranteed.

    73 from Ian GM3SEK
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  18. Ken G3SDW

    Ken G3SDW Moderator

    Every little helps Ian, thanks for your input.
    Hope you are well
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  19. M6VWM

    M6VWM Member

    Thanks both.

    Got to witness the transition from no noise to s9.

    I turned on the radio at lunchtime and zero noise, picking up some dx on 20m too.

    Got home before my neighbours and left the radio on a clear bit of the band.

    The lady came home and nothing but within 10 minutes of the husband coming home the noise went straight upto 9 again.

    Interestingly the noise vanished again I just before I heard them walking up the stairs (it’s a semi).

    Could suggest it’s their tv? I guess I need to get the courage to ask if they have a plasma.

    The phase theory sounds interesting but how would I check?
  20. M6VWM

    M6VWM Member

    Yup completely noise free now.

    Now it’s all clear I’ve been around my house turning things on to see if anything inside is creating noise

    Interesting to find my rather expensive pc is creating s5 noise floor on 20m my sage coffee machine underneath my room seems to be s3 in standby too. Now looks like when I was getting s3 before it was because my coffee machine was in standby. My tv did nothing.

    Attached Files:

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