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Power line noise.
11331 Khz and various other bands, frequencies etc. emeraldsdr.ddns.net:8073/
It's not nearly as bad now as it was earlier, I was using a MFJ power line noise detector and thought I found the pole responsible but now I'm not so sure.
First I drove around in the car parallel to the offending 3 phase line that runs over my Garden ( of course it does ) with the Am radio on until I heard a spike in noise, I got out into a field and pointed the MFJ at one pole, I could hear noise but it wasn't the pole, I went to the next pole and the MFJ needle was hopping , went to the next pole and the next but the noise wasn't nearly as bad.
Today I went to the same pole and the noise wasn't nearly as bad on the MFJ but the noise on the SDR was bad, very bad and the portable AM radio didn't have the same noise under that pole as it does in my garden.
So now I'm wondering is it the pole in my garden or not ? I'm really devastated as My SDR was one of the quietest Kiwi's on the net , I also feel this is interfering with my 4G internet.
I live in the sticks here in Ireland and accessing electric poles is a challenge, lots of fields separated by large hedges, barbed wire, electric fences and locked gates, not to mention cattle ( bulls ) and crops, at least most of the harvest is in now.
I contacted the electric company several weeks ago and heard nothing.
If I could say with absolute certainly that there's a particular pole causing the issue they might just fix it.
The MFJ works on VHF , I doubt UHF would be much better because I live in the sticks there's not so many poles on top of each other. I got the MFJ because I don't have a VHF / UHF radio and to buy one + Dipole would have cost as much or more and I've no use for a VHF /Uhf radio.
The problem with driving around with the AM radio is that the poles are mostly not close to the road and the noise I hear is not the same as the noise I hear in my garden on AM.
Any advice would be greatly appreciated.
It's not nearly as bad now as it was earlier, I was using a MFJ power line noise detector and thought I found the pole responsible but now I'm not so sure.
First I drove around in the car parallel to the offending 3 phase line that runs over my Garden ( of course it does ) with the Am radio on until I heard a spike in noise, I got out into a field and pointed the MFJ at one pole, I could hear noise but it wasn't the pole, I went to the next pole and the MFJ needle was hopping , went to the next pole and the next but the noise wasn't nearly as bad.
Today I went to the same pole and the noise wasn't nearly as bad on the MFJ but the noise on the SDR was bad, very bad and the portable AM radio didn't have the same noise under that pole as it does in my garden.
So now I'm wondering is it the pole in my garden or not ? I'm really devastated as My SDR was one of the quietest Kiwi's on the net , I also feel this is interfering with my 4G internet.
I live in the sticks here in Ireland and accessing electric poles is a challenge, lots of fields separated by large hedges, barbed wire, electric fences and locked gates, not to mention cattle ( bulls ) and crops, at least most of the harvest is in now.
I contacted the electric company several weeks ago and heard nothing.
If I could say with absolute certainly that there's a particular pole causing the issue they might just fix it.
The MFJ works on VHF , I doubt UHF would be much better because I live in the sticks there's not so many poles on top of each other. I got the MFJ because I don't have a VHF / UHF radio and to buy one + Dipole would have cost as much or more and I've no use for a VHF /Uhf radio.
The problem with driving around with the AM radio is that the poles are mostly not close to the road and the noise I hear is not the same as the noise I hear in my garden on AM.
Any advice would be greatly appreciated.
Comments
Power lines are particuarly problematic as the noise can be transmitted over a very wide area some considerable distance from the actual source.
If it is arcing you should be able to hear it at the pole (if it is at a pole and not a dead animal or foliage actually across the line and becoming carbonised), as very often it is a cracked insulator that has got water or dirt in the crack and the electricity is tracking along it.
The big problem is that you get standing wave patterns on the lines and as a result, even though the source of the noise may be broadband, the standing waves mean that different parts of the line radiate more at certain frequencies than others, so you may get a lot of noise at say 11MHz in one location, but at 5MHz in another. The long length if the lines can also mean that the noise is radiated along the length of the line (like a Beverage antenna) rather than at right angles like a dipole.
I think you may have to build a small tuned loop antenna to DF the source at the frequencies of interest by means of triangulation and signal strength observations.
I use the QRP loop shown on this webpage for DFing noise sources.
https://www.g8jnj.net/hfloopantennas.htm
I also have a broadband AM detector (two transistors as untuned RF amps followed by a diode detector and AF amp) that is handy to use with the loop as a simple TRF receiver. If I just use the AM detector with a telescopic antenna, I can often just walk around and gradually telescope the whip down as I get closer to the source.
I have found that generally the electricity distribution companies (and not the suppliers you buy the electicity from) are fairly proactive with respect to line faults, maybe you just need to find someone else at the company who is more interested in fixing it prior to a catastrophic failure.
Good luck,
Martin - G8JNJ
Ron
KA7U
Attachments:
https://forum.kiwisdr.com/uploads/Uploader/35/942784cf36be6a0303d47688d3dedc.png
I connected to my SDR yesterday morning to see a just astonishing, not see before (even here) level of noise. Here 98% is from one neighbour who makes a living from gaming and Youtube, the authorities even when handed information on a plate won't do anything unless I can prove it is stopping me from HAM contact I could make before.
It's like saying my neighbour is dumping on my path but the regulator won't react until there is nowhere left to step, makes a mockery of the whole electrical compliance rules.
I cant't quite tell from your posted screen grab but that looks like it could be VDSL interference from the broadband over copper pone lines.
If you look at the frequency plan for VDSL in this information leaflet http://rsgb.org/main/files/2012/11/VDSL-Interference-v3b-.pdf you can see that the main blocks of noise seem to be associated with the Upstream bands.
In many cases this problem is due to incorrectly fitted phone extension wiring in the home. If you are on speaking terms with the guy, you could try the tactic of what broadband speed are you getting ? You may be able to improve it by fitting the correct BT filter plate and wiring the VDSL modem directly to the VDSL port on the plate.
If it's not VDSL it could be that he is using some Ethernet over power line adaptors. These can also interfere with VDSL speeds, so the tactic here is to mention this and suggest that if it's replaced with wired Ethernet cable he may get faster speeds.
In most cases folks don't actually need faster internet speeds, but if the guy is a gamer or just partially tech savvy, and thinks that having more speed will give him some sort of advantage, he may take the bait and do something about it.
The other problem is modified 'gaming' PC's with coloured lights & fans, with clear plastic sides on the PC so that his mates can see the 'souped up' internals. These are a real problem as the case is no longer effectively screened and all the internals running at high clock speeds tend to radiate, but again the "it could interfere with you internet speed due to interference with the VDSL" may possibly work.
Another tactic I have successfully used in the past with more general cases of interference goes something like this.
Go and visit the neighbour and look as 'concerned' as possible.
"Hello, I'm sorry to disturb you, I hope this isn't a bad time to call." (be polite at all times)
"I'm your neighbour ( name) and I enjoy listening to short wave radio broadcasts."
"I've recently noticed some radio interference which I think is coming from your property."
"I wouldn't normally bother to mention this, but I was slightly concerned that the interference could be an indication of something becoming faulty, probably an electrical appliance, and I was worried that it could possibly at some stage become a fire risk." (all true)
"I didn't know if you were aware of this, but I thought you should know."
"If you wish I can give you some contact details of organisations who can locate the source for you, but they do tend to charge for a callout." (all true)
Alternatively with your assitance I could try to locate it, if that would be of help to you."
Modify as required to fit the situation.
In many cases, it's sometimes more effective to just plant the 'seed' of an idea, and encourage it to grow, rather than direct confrontation, which often has the opposite effect. You just have to figure out the psychology of your 'opponent' and what triggers can be used to either get them on your side, or do something they consider is a benefit or advantageous to themselves (or ideally both), rather than doing someone they don't know a favour (possibly involving time or cost implications) for no obvious return.
Regards,
Martin - G8JNJ
He has SkyQ that uses mains networking and I recognise the impact (annoying but I can still receive) but his most powerful PC PSU is just awful and I can recognise that terrible din (5-10MHz worst) and signature waterfall pattern over 25-30MHz.
This is something else, maybe he has gone to some Tesla coil lighting and replaced his mouse with an arc welder.
I hardly talk to the guy and he is not exactly open with what kit he runs (other than the stuff he puts online).
I need to convince a local farmer to let me build a self contained remote station, that will be the end of it.
Stu
OK - Arrghhh SkyQ they used to ship the set top boxes with the data over the mains supply enabled by default, I think they have now changed it to off, but it's still not good.
He would probably not be happy if his internet dropped out every time you transmitted and may be tempted to fix some of the causes, but sometimes it's just not worth starting a '(un)civil' war with your neighbours, as they can often end up behaving even worse than you could ever imagine :-(
Regards,
Martin - G8JNJ
From other research I believe it is possible to turn mains networking "off" with SkyQ but it is not possible to disable the hardware, so "off" is actually "on, but not used for networking" can't make this stuff up.
The phone lines are underground here so it would be fairly safe to TX without disturbing anybody (unintentionally obviously). If I was minded to set up a situation where the noise fulfilled the criteria for investigation so many current devices almost seem designed to disrupt other RF use it would probably only fix things for a week or two.
I guess I have a challenge to create a self contained and powered system that hopefully doesn't get trampled by cows or stolen for scrap.
Regards
Stu
The noise is hardly noticeable now at this time today, what it was like earlier I do not know as I had no time to check.
Yesterday it was very bad and it effected several bands I just used 11331 Khz because it was particularly bad at that time.
If I could get a general idea of the location it would be a start, I used the AM radio in the car but the poles are really too far from the road at times in the middle of fields and it's a tough job just to walk from one field to another and if I could find the general direction It would be a start.
The issue is that the noise will be travelling along the line from xx Kms away and it's bad enough in my garden directly under the wires but it's intermittent and I think it might be due to a higher load at certain times, it's definitely far worse that it used to be and late at night it's not much of an issue which leads me to believe it's due to load.
The MFJ and dipole is good , very good when you're practically on top of a noise source but I need something that might point me towards the direction of the actual source.
Martin , your suggestions look good , unfortunately I don't have a lot of time for building things, I've two small Boys and they take up most of my free time but you heard how bad it can be. It does sound like arching of some sort and it sometimes sounds as if wires are shaking and you know what ? yesterday was a good bit windier too.
My greatest challenge is getting from one field to the next.
It's so strange because today it's quiet as a mouse. It's fantastic. It's pretty windy too and making no difference so it's not wind related.
I hope there isn't another issue somewhere else that's causing the constant noise at times.
See the Pic , this is the pole , when I shake it , I hear buzzing consistent with wires shaking or something else with the wires, perhaps a bad join. I tried several times, quiet then when I shake the pole it keeps coming back. I'm just wondering now is the noise worse due to the load on that line ?
See the pics, there's a 3 phase line and a single phase feed to the transformer on another pole feeding the farmhouse.
Is the other farm a diary, does it tie up with milking?
I wonder if that has got some insulation breaking down ?
The rest looks fairly clean.
Regards,
Martin - G8JNJ
@Powernumpty , no dairy at this Farm but because it's usually quiet as a mouse at night it leads me to believe it's load related mostly, probably arching over bad or corroded connections etc made worse by higher currents ?
Remember that pole to the right with the transformer in the pic above ? well as luck would have it, a storm came last week and the tree in the pic fell on top of the pole snapping it haha , that was about 10 am, by 6 pm a new pole and all new cabling from the 3 phase line all the way to the farmhouse was installed and it eliminated almost all that noise I was getting. Talk about luck ? despite several attempts to get the attention of the power company they wouldn't as much as give me a phone call so haha to them and a big thank you to Mother Nature.
But as one noise source disappears another appears and if you go to my Kiwi Sdr emeraldsdr.ddns.net:8073/ and tune to around 3200 Khz and look around 80 meters and you'll see this new noise and for the life of me I simply can't find it.
I have a MFJ powerline noise detector which is great but it works on VHF and you need to be pretty close to the source and I'm puzzled as to what I can use to try get a direction of the noise ? it's nothing in my house and it seems to be on timer it starts around 8 pm UTC and ends at exactly 12:53 am UTC every night which leads me to believe it's something a neighbour has on timer but my neighbours are not that close. It has all tha hallmarks of LED light with filthy SMP. But what the hell ? I walked around with the MFJ and nothing, the noise isn't nearly as broadband as the powerline noise.
Here's a pic of my QTH and surrounding area , as you can see I'm not exactly in a built up area, the red balloon is my QTH and the house to the left is the farmhouse.
So if the noise isn't as broadband perhaps the MFJ detector won't be of any use ? I tried to use my Tecsun PL-880 and while it can hear the noise it can't find the direction.
The power line noise is 99.5 % gone , I have a hint of power line noise in the evening but nothing of concern and daytime reception is blissfully quiet.
This new noise is really got me puzzled.
It's quiet as a mouse mostly during the day but around 20:00 UTC it starts and at 1:53 AM UTC like clockwork every night it's gone. You can hear it around 80 Meters ham and around 3.2 Mhz, once you know what you're looking for it's easy to spot elsewhere.
So I pointed him to the new pole and cabling and told him that's thanks to Mother Nature :-)
You couldn't make it up ! brilliant !
Anyway turns out they tried to find the house before on a few occasions and had the wrong number for me but they eventually got the email from the office with my details.
They said they do take these issues seriously.
Storming service levels.
Now if I could find that source of QRM from 8PM - 1am UTC I would be very happy.
Makes me think ventilation fan, or dairy type use -steam, pasturisation etc.
Underground water storage (topped up same part of the day)
I suppose you could try to find out the electricity low rate times in your area and see if it relates to that.
Does it change with temperature or sunset? do any events locally change the time E.G. more visitors longer duration?
I kind of like these problems.
I would go visit your SDR but the low noise level would probably make me too jealous.
Stu
The noise is like something that's on a timer, it's really strange, timers don't usually go on outside floodlights which is what I expect this is, it's the same time every evening about 20:00 UTC to 1am UTC.
It's a real pain in the ass to try find out what it is especially since it's dark a lot earlier.
Just a random marginal station on 40m, both of them.
I should be clever and work out how to properly use the recorder script to synchronise the recording but it's late and I was just playing. I'll email you the two recordings (about 6mb each) if you are interested (PM Me).
Nice low noise on the new 10m but it is competing with your other antenna which is already excellent. I expect more serious users will have things to say about the LW/MW performance or some other aspect I just won't appreciate.
Is there a way to route receivers to one stereo channel, I'd buy a white cat to stroke if I could be remotely listening to two SDR's at the same time from my volcano bunker. I could use the audio delay John mentioned before to really phase my brain (?).
So give them a go again, strangely I can' understand this, emerald is suffering from QRM related to the SMP powering emerald1 which is not hearing this noise ? what ? I thought it was the Wine last night but it was the same this afternoon, plugged out emerald1 SMP and emerald was a lot quieter, I seriously don't understand how this can not effect the kiwi it's plugged into ?
Anyway, I got a linear supply which will power both, emerald is powered by a linear, I need to get one for emerald1.
Anyway the correct url's are
emeraldsdr.ddns.net:8074/
emeraldsdr1.ddns.net:8073/
It will say which Antenna is in use which will indicate it's definitely the two different sdr's if not please let me know for instance if both URL's link to the one Kiwi.