HF interference on my ring main?

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

  1. M0JAV

    M0JAV Moderator

    any conductor particularly one not earthed will act as a passive re-radiater just like directors on a yagi. If it is near 0.25 or 0.5 wavelength long it will have gain.
    You could try asking the neighbour what is plugged in in their house near the hotspots but be careful about how you approach them. Ken is the expert at neighbours and will give some sound advice.
    John M0JAV
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  2. Ken G3SDW

    Ken G3SDW Moderator

    The fact that you totally switched off the mains supply at the fuse box and the noise went away then that proves that it is coming from something within your house, going close to walls which have mains wiring within them will always give an increase in noise using a portable radio.

    It seems that when you do not use your PSU and use batteries the noise goes away that is why i wanted you to try and borrow another one just to prove me wrong.

    I think you are now realising how much RFI is being radiated from the average home, going up close to a piece of kit will give you pick up but as long as the distance it is radiated is within limits then you are OK its the non compliant ones that give us in our hobby a head ache.
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  3. Ken G3SDW

    Ken G3SDW Moderator

    Just been trawling around about your PSU Diamond GZV4000, and seems as though the can suffer from noise, sadly SMPS PSU can suffer in this way.

    Judt looking and i think you would have been better getting the GZV3000 which is a Linear PSU and would not suffer with a noise problem.

    Let you take a read of the reviews https://www.eham.net/reviews/detail/660
  4. M6VWM

    M6VWM Member

    A little progress although still not resolved entirely, my rig is now usable.

    I initially moved the extension lead and my noise dropped off. I have also moved the PSU further away from the station and that too seems to have reduced it further to around s4 great progress with an S9+ start!

    Quite worryingly I have discovered some sockets create more noise than others suggesting a problem in my wiring or sockets. I seems I may have a bad earth or some kind of issues with a certain few sockets, bizarrely the number 1 suspect socket is directly above the hotspot, so maybe not my neighbour after all?

    This one room has blown some fuses in the process of testing and even killed a surge protector yesterday. Suffice to say isolated it and I have an electrician coming to do a full circuit test and resolve later but I must admit I wonder if I hadn't started radio would I even have realised something was wrong? Probably not.

    With regards to the PSU, I did originally buy a Linear PSU but it made a horrible buzzing noise due to vibrations so I returned it. MLS only had switching ones at the time so I opted for the 4000 as it was available. With hindsight I should have waited for linear stock.
  5. Ken G3SDW

    Ken G3SDW Moderator

    Good news and from what you say, and your symptoms i must say are rather odd, different sockets giving different amount of noise, so i feel you are right to get you house wiring checked over, do you know when it was last wired, before your time i expect.

    Yes it is a shame that you did not wait for a linear PSU, but in the defence of SMPS then they are not all rogues, but choosing one for amateur radio use is important and as i speak my TS480SAT is silent, S0 on 40m, and i use an Alinco SMPS which is silent and was designed with us in mind, most SMPS do not give any problem at all, it all depends of how they are designed and if so are silent.

    For you as a newly licence`d amateur then choosing the correct kit is a nightmare but we are here to guide you through when needed too.

    Let us know the verdict of the electrical check you are having later.
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  6. M6VWM

    M6VWM Member

    Absolutely right on the equipment choices, its such a minefield and the learning certainly hasn't stopped, there is always the next hurdle to navigate. Still to make my first contact but I hope to get going soon! I'm told 40m is ok at the moment, 20m seems dormant.

    I have lived in this house since 2000 and it was built in about 86. I don't think the wiring has ever been touched in that time. There have been some issues with light switches and bulbs blowing in the past 12 months so it seems a good time to get it all tested properly and get an RCD panel instead of the original fusebox.

    After discussing with my electrician brother he suspects I may bad connections in one or more sockets and potential arcing. Plugging in a extension with a light on it, the light was flickering on and off randomly. I'm no electrician but that doesn't seem right and I've stopped using the sockets that are doing that entirely.
  7. Ken G3SDW

    Ken G3SDW Moderator

    Yes think you are on the right track, so look forward to hearing what your brother finds when he call later.

    Its a shame that today newly licence`d amateurs dont have the initial time to find out what it is all about, talking with others at a local club which give them a good grounding to start them on there journey into going on the air, but suppose that was when i was first licence`d in 1963, things have moved on since then for the better well not sure on that one..

    Do you belong to a local club, if you dont then it maybe a good idea to join one as you will get loads of support in times of need.
  8. M6VWM

    M6VWM Member

    Thankfully the local club have been really great and put up with my constant questions on everything and anything.

    I managed to do my foundation exam with them although I didn't actually do any training, just lots of reading and mock exams. Only got 1 question wrong but at the same time it's far from enough information to really get going in my humble opinion. Daunting isnt the word.

    I understand soon some elements of the Intermediate will move into Foundation, probably a good plan.
  9. Ken G3SDW

    Ken G3SDW Moderator

    I love to see from a newly licence`d guy what you said here ie with my constant questions on everything and anything, brilliant mate, keep it up

    Let me know the outcome of your brothers visit if you could
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  10. M6VWM

    M6VWM Member


    No firm news as yet, it was a bit late last night so he is coming back to do full checks. Apparently I am getting tiny pulses on that ringmain, apparently usually arcing on a bad connection (or from a worn out socket). So fuse out for now and first step to check all connections and probably replace my sockets to be safe. They are all 32 years old so seems sensible anyway. Fingers crossed its not wiring though.

    With regards to the EMC Ive realised through checking how it was lots of little things combining to create a bigger problem.

    Discussions suggests he does think arcing/sparking can cause pulses of interference but he doesnt really know radio very well so suspected it could contribute but couldn't be 100% certain. He says first time he's ever been asked RF questions ;). Certainly pulses can't be good for my equipment.

    I may actually talk to someone on the air one day haha. Although I may also just pop the rig in my camper, drive to a hillside and string up an end fed instead :D
  11. Ken G3SDW

    Ken G3SDW Moderator

    Hi mate, OK then we will see what the man has to say, yes i had a similar problem, not a noise one, but similar age switches and sockets looking rather dodgy, so i just replaced them all as the make of the original ones were suspect if nothing else, considering how much your rig has cost you then a small price to pay

    Think you are on the right track.
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  12. M6VWM

    M6VWM Member

    Thankyou, appreciate all your advice!
  13. Ken G3SDW

    Ken G3SDW Moderator

    You are more than welcome, that is what i am here for.

    Talk again soon.
  14. Ken G3SDW

    Ken G3SDW Moderator

    Hi Matt, how is it going?
  15. M6VWM

    M6VWM Member

    Morning Ken,

    Very good now, the new sockets have helped with the noise far more than I expected. I got hold of some multi adapters with RFI filters just in case too not sure how effective they will be.

    There is still a rare intermittent pulse that seems to appears periodically but I believe this is not within my own home now. Whatever it is even glitches my wifi amongst other things. On HF its like a tiny click and a spike of signal upto 9+ then gone as quick as it came. I'll be chatting to my neighbour in case something in there has issues, maybe they have a plasma tv or something that is switching.

    I have also learnt a great deal about what is interfering in the home with the radio. I have moved the antenna a little further away from my house which has also helped. Having the PSU on a slightly longer wire has also stopped that interfering. As long as I turn off the garage power (near the antenna) its much better. I am at good times seeing no noise at all which is amazing, literally able to pick up faint S1 signals.

    There are times of the day when it just goes again and I suspect its things like neighbours washing machines, or microwaves being on (starting to recognise the noise sound they give off from my experiments and investigations at home).

    I feel we've turned a corner and I can now contentrate on getting the new G5RV up properly so I can actually make some contacts. It all starts here!
  16. M6VWM

    M6VWM Member

    Oh and ferrites, so many ferrites!
  17. Ken G3SDW

    Ken G3SDW Moderator

    Great News Matt.

    You will always get some interference mainly on the LF bands from time to time as most households emit bits and pieces from time to time but not permanently.

    If your neighbour has a Plasma then you would know it as they emit an almighty din across all of the bands which sounds like a rasping noise that alters all the time.

    Clicking noises are often no more that a worn central heating thermostat that is on its last legs, if it is then you will not notice it so much as we enter the summer time.

    Glad that all is in the clear, i knew we would get there in the end, you know were i am if you need any help with anything at all, would be my pleasure, i will close you case now.

    Good luck and enjoy our great hobby.
  18. M6VWM

    M6VWM Member

    Well it didn't last sadly I am back to S7 noise levels permanently on 20m, 8 or worse on 40m. I did find a bad earth in a socket which has been repaired but hasn't resolved the noise sadly.

    Once again only solution is turning off the mains, even with every plug in the house unplugged or off the noise is there. Turn off the mains, gone. This suggests its either the mains itself, or the PSU (Diamond switching).

    I am even now getting a weird interference noise on 2m band too but without any signal noise. Odd.

    I've added even more ferrites and even got RFI filtered multiplugs in several rooms and on the radio but to no avail.
  19. M6VWM

    M6VWM Member

    Oh occasionally in the morning it drops to S6 weirdly.
  20. Ken G3SDW

    Ken G3SDW Moderator

    Well if you have turned off all your mains supply and the RFI goes then it is something connected to it within your house,if its gone when it is off then it cannot be coming from anywhere else.

    If you unplug every thing individually and it i still there then there is still something connected, you must investigate this.

    There must be something wired direct or hidden somewhere within your house, if nothing is connected to your mains supply then it alone cannot radiate RFI.

    You need to investigate much deeper.

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