HF interference on my ring main?

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

  1. Ken G3SDW

    Ken G3SDW Moderator

    Well sort out your own noise first then you will have to ask your neighbour if they could help you with some tests.
    Just choose your words carefully and pick a time that feels right just to make sure you don't catch them when they are busy.
    Seems as your observations are spot on so take your time and I am sure they will cooperate.
    73
    Ken
    G3SDW
  2. M6VWM

    M6VWM Member



    Found a real hotspot in the wall behind my tv. As you will see my tv and speakers barely gives off anything in standby. Even with the routers near here the wall is a lot louder than anything else. I assume as our houses are mirror images that this is where the neighbours tv is.

    Anyone recognise the kind of sound?
  3. Ken G3SDW

    Ken G3SDW Moderator

    Must admit that it sounds very similar to Plasma TV, and with your explanation earlier today about your neighbours movements yesterday that it may well be there TV, being it will be behind the wall that is in your video.

    We have to prove that it is that causing the problem first, but if it is a Plasma TV and it must be an old one at that then we have a major problem, let us hope that it is not that and just a noisy SMPS in a LED/LCD TV.
  4. M6VWM

    M6VWM Member

    So confirmed that the neighbours have a plasma tv, and they agreed to unplug it to help me test.

    The s9 noise did indeed disappear once it was off and unplugged but there was still an underlying s7 noise left behind at the time of testing. No idea what this could be. I put some clamp ferrites on the various cables of the tv but no effect.

    As this s7 also disappears in rare instances when the tv isn’t on so I am somewhat at a loss as to where this other source is coming from.
  5. M6VWM

    M6VWM Member

    In summary it’s a complicated noise situation and without a proper rf detector I think I’m unlikely to track it down. Local club hasn’t been able to help and don’t have any detectors I can borrow.
  6. Ken G3SDW

    Ken G3SDW Moderator

    Right, this is something i know a lot about as many years ago i negotiated with Panasonic and Samsung for them once reported to them in the correct way for them to exchange the set for a brand new LED TV at no cost whatsoever, LG would not get involved, sadly.

    About 12 month ago both Panasonic and Samsung decided that after 5 years of there help that as all Plasma TV`s were well out or warranty and getting quite old that they could no longer help, which was quite understandable.

    Again sadly there is now way that any amount of ferrites will make any difference at all as the RFI is radiated from the Plasma Screen its self.

    Plasma TV`s give this problem once the Plasma panel starts to drop in output and the software ramps up the drive then all hell is let loose, they have been a pain in th back side for amateurs for many years now.

    So other than if they replace the TV, which is doubtful or you supply them with a new TV then we are completely stuffed.

    As for the other s7 noise then that will have to be located separately, again most RFI problems are from multiple sources, in your case this will appear to be the case.

    I know that this is not what you want to know but there set is rather old now and will no doubt pack us eventually
  7. Ken G3SDW

    Ken G3SDW Moderator

    You dont need an RF detector mate just a portable receiver, which club does not want to help you, that is not acceptable, finally what make is the TV??
  8. M6VWM

    M6VWM Member

    I don’t think it’s that they don’t want to help more they can’t help beyond the advice already given. I’ve had advice from a few members but none of it has worked sadly. In fact many have the exact same problem at home as me.

    I’ll ask at the next meet again but generally there seems no solution beyond turning the street off :D

    I am assuming no amount of inline isolators/chokes or a suitable device to remove inference will help?
  9. M6VWM

    M6VWM Member

    I’ll check on the Tv make I forgot to take note.
  10. M6VWM

    M6VWM Member

    So a mobile Hf radio would be able to help locate it?

    How would I go about doing it? Would the signal spike near to the object?
  11. Ken G3SDW

    Ken G3SDW Moderator

    You really need a hand held radio that covers HF, and what you do is to get a simple bearing and as the noise gets stronger reduce the antenna until it is so strong that you can take the antenna off and it will still be there, this now means that you are on top of it.

    It no doubt will be an SMPS, everyone has several in there homes, most are quiet but some are noisy.

    I would have thought that a member of your club would have offer`d to come ver to your house and help you locate the problem, this being the spirit of amateur radio by helping others, especially you being new to the hobby.

    Your final comment about line chokes etc, as i said the noise is not being radiated into the mains or antenna but just from the Plasma panel, and there is loads of it, if you can just imagine millions and millions of little lightning strikes happening all at once inside the Plasma panel, that is what is causing your problem.

    I have spent the last 5 years or so working on this problem and if there was a way i would have found it, and surely if the manufacturers knew how to stop it then they would have said so, if the correct standards were taken when they first were trialed then they would not be on the market at all, they are the nature of the beast.

    I managed to replace many here in the UK along with several in the EU and Scandinavia along with one in New Zealand, sadly it had to come to an end eventually.

    As for the noise that remains then maybe it would be a good start, as you are now on talking terms with your neighbour to ask him, or her, if they would not mind turning off there mains supply just to eliminate then out of the equation.
    M6VWM likes this.
  12. M6VWM

    M6VWM Member

    Thanks Ken,

    I had a wonderful day of no noise again and was getting New York on 20m. I time checking my own equipment. Found a noisy battery charger and a NAS drive that was creating a lot of noise to. Moving the NAS to an RF protected multiplug in another room seems to have sorted it.


    Sure enough the neighbour came home from work and I started getting clicking spikes of rf going upto 6 and instantly vanishing. After a few minutes more the noise went up to 6 or 7 and stayed there and as the night progressed it was upto 8 or 9 after dark.

    I asked for help via our club forum but no one in my club seemed to have a hand held Hf to help. I’ll ask in person at or next week.

    Plan is to discuss again with my neighbour and take my am radio. I’ll ask the model too although I recall it was perhaps LG. My own experience of LG isn’t great with regards to customer care.
  13. M6VWM

    M6VWM Member

    excuse my bad spelling, I am using phone to type.
  14. Ken G3SDW

    Ken G3SDW Moderator

    You have hit the nail right on the head, LG were most uncooperative when i was negotiating along with the others, they even stated after Ofcom had confirmed that it was on of there sets causing the problem saying "What has Ofcom got to do with it" some technical help line.

    I think your main concern should be with your neighbour to see if he will cooperate, once, and hopefully he will, then you can concentrate on any others that are they, its not a good idea to try to sort out more than one at a time.
    M6VWM likes this.
  15. Ken G3SDW

    Ken G3SDW Moderator

    Not a problem, have have the same grief on my phone.
  16. M6VWM

    M6VWM Member

    My experience with LG was buying a tv and Blu-ray player. The Blu-ray player was supposed to support streaming services but out of the box they weren’t present. Initial queries with support stated it was being developed. After 8 months and no updates I raised a complain. They simply stated they wouldn’t be updating it further and a newer model provided the features. Despite the box and advertising promising these features they just washed their hands of it with a screw you attitude. I promised myself I’d never give them any of my money again.
  17. Ken G3SDW

    Ken G3SDW Moderator

    This is how i feel about the poor treatment we had, lots of guys listened but once it went higher it was shut down.

    Quite the reverse with Panasonic and Samsung they could not be more helpfull.

    Keep in touch.
  18. M6VWM

    M6VWM Member

  19. Ken G3SDW

    Ken G3SDW Moderator

    Made in the PRC and as you say CE marked, Chinese Export, sadly today the CE mark stands for nothing.

    It should be a guide that proves conformity, not the case anymore.

    Trading Standards, what standards?
  20. M6VWM

    M6VWM Member

    Well great news is a local radio amateur has agreed to come and help me track the interference. He is very experienced (in fact he makes some well known antennas), so I am really confident we will work out what it is.

    In the meantime I've been mapping the noise floor hour by hour over the last couple of days where possible to try and pinpoint a battery and the times it's gone on and off. He seems confident that we can track and resolve it but also he believes he can give antenna advice to reduce it too.

    Fingers crossed, thanks for your continued support and Ill keep you updated when he has popped round.

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