Power Line Adapter noise interference solution?

I have been writing these posts as multi-subject essays but I hope from now on to do just one thing at a time and just make more posts (!).

About 3 weeks ago our neighbour installed power line adapters. The PLAs in question were branded TP-Link but there are lots of makes. Some make less noise than others.

How did I know that my neighbour had installed these? Well, the 50MHz band was immediately submerged under a wall of radio noise. Much tinkering with the Noise Blanker settings on the Icom IC-7300 allowed me to separate out two distinct types of noise - 1st a sound like a chicken clucking which was there 24 hours per day and - 2nd a wideband swoosh of white noise of varying strength which happened at certain times. Presumably a constant status signal with wideband saw-tooth type signal when data was being exchanged.

Sudden peaks in the wideband noise and regular "clucking" all the time.

At this point I am going to try to upload a video clip to this blog. If it works it shows an unsteady image of the IC-7300 receiving the noise, and at one point me turning the noise blanker on to reveal the two separate components. As I have never managed to upload video successfully to this blog platform we shall see if I can get it to work.

Although the noise blanker could be made fairly effective against both noises this required me to adjust it to maximum settings. When I did that reception of FT8 was affected. So with NB on I could combat the noise to a large extent, but then I could not use the radio. Turning the noise blanker off pushed the AGC into overdrive and signals vanished.

This is always a difficult situation as my neighbour was simply following the advice of our local television antenna/satellite dish installer. This particular installer loves installing Power Line Adapters (PLAs). The idea of the PLA is that it works by injecting an RF signal down the house mains supply wires and then receives the signal somewhere else. The units are fitted with Ethernet sockets, and in this case were connected to an internet router at one end and a television at the other end. They are cheap, and easier than cabling the house. So he uses them a lot.

I needed to be pretty certain that the noise was coming from this source. It is not easy to approach a neighbour and suggest that something they have just bought is causing me problems when it is clearly not causing them problems. Especially if you have picked the wrong house to blame. So, amongst other things, I swung my beam round to see if the noise was directional (if it isn't it is probably coming from this house). The neighbour's house is located South West of me so I took compass bearings as I turned the beam.

This is not the first time this has happened to me. Last year my neighbour on the other (East) side had a similar experience. She had installed a proprietary internet TV system supplied by BT, and the same installer fed it using a pair of BT branded PLA adapters. The resulting noise then was FAR worse than this time, as it was clearly getting into the mains supply of this house. That problem was resolved by the neighbour accepting my offer of a wi-fi alternative to the PLAs.

So I offered the same solution to the second neighbour with the latest PLA installation. He told me that the installer had tested the wifi signal and that no reliable wifi could be found at the television end so the installer had sold him the PLAs. I offered to try out a wifi solution at no cost to him. He agreed to this and I followed the same process as before. The device I tried was the same as before and still listed on Amazon as:-

DC XINGDONGCHI Wireless-N 300Mbps WiFi Range Extender Router/Repeater/AP/Wps Mini Dual External Antennas Wifi Booster Wireless Access Point with RJ45 Port (Wi-Fi Booster)

Hyped up to sound like a pretty amazing product, eh? You can find it here for £14.99:-

https://www.amazon.co.uk/gp/product/B071L939FZ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

EDIT:- In the past couple of years it has gone up to nearly £25. I cannot keep up with the price but it was still available last time I checked. The first system has now been in use without fault for 4 years.

Whatever else it can claim to do (it is basically a wi-fi repeater), it has two key features for me. First it has two Ethernet sockets and can provide an Ethernet output for wi-fi links. And secondly, it has a very sensitive wifi receiver. It doesn't photograph very well:-

The wifi to Ethernet hub as bought from Amazon (inverted photo)

Anyway, over the past year I have bought 4 of them to solve various similar problems. The neighbours on both sides now have them to replace noisy PLA systems, and in both cases the noise level has fallen back to negligible. I also have one myself which gives a perfect picture on our television, whereas the on-board wifi cannot find a satisfactory signal. I fit them with CAT6 cables to reduce RF interference (both in and out!) and set them up for repeater mode on the domestic wifi. Then I just connect the Ethernet cable to the television.

There are two Ethernet sockets, so a fourth one has been used by me to provide a wifi fed local area wired network for two computers. This is not completely noise free but pretty good - certainly miles better than PLAs could produce.

I had expected to have to fit a repeater to reach the television in the case of the second neighbour. After all, the TV installer had said that the weak wifi signal required him to sell them a set of PLAs. As it turned out the XINGDONGCHI device got a perfectly good signal from the domestic router located at the other end of the (large) house.

No doubt other products are available which do the same job, but these ones suit me. They are cheap and effective. Some reviews say they are unreliable in the long term, but the first system has now been operational for a year.

Hub turned on and sending data to GM4FVM's LG television via the cable

Perhaps the main drawback is the bright blinking LED light display. Homer Simpson from the popular television cartoon series "The Simpsons" has a solution for this type of thing. He sticks some black tape over his annoying car "low oil level" warning light  Perhaps for this in a domestic setting we might use neat white insulating tape. Note that with UK plugs the device appears upside down. The upper photo has been reversed by me, the lower one shows the device as it actually appears - upside down.

Anyway, in my view PLAs are terrible. They are supposed to be "notched" so as not to produce signals on amateur bands, but the TP Link ones produced nasty noises on the 50MHz bands - but not on 28, 70 or 144MHz. Anyway, the best solution seemed to me to remove them entirely.

We will need to see in the long term how effective these are. Mind you, for a year now the first one is providing a reliable signal to a BT box. That device happily streams high definition video (so does mine for our TV). Bandwidth does not seem to be a problem. The resulting data speed has so far proved just fine for my neighbours and me.

All this makes me think of a different issue. BT supply their steaming box (which is a hybrid "Freeview" digital TV recorder and internet decoder) with only an Ethernet socket for connectivity. At the same time they advertise their Broadband internet service as having the best router and wifi signal available. Do they not trust their wifi signal to supply their television box? So far I find that my neighbours are perfectly happy to have wifi connections instead.

And I am perfectly happy to stop all that noise.

This is bad business for BT. I decided not to buy their box as unless it was right beside a router it could only be supplied with PLAs. Now I discover that was never true. In these three installations PLAs are not necessary for domestic television viewing.

Final thought - you might have PLAs in your own house. It might be worth doing away with them and I am sure you can come up with a solution - maybe hard wiring using at least CAT6 cable?

Power Line Adapters? I say "Down with this type of thing".

73

Jim
GM4FVM

Merry Christmas, more noise and some updates

First of all, have a great Christmas. If you don't celebrate the religious festival then have a good cultural Christmas. You might as well because there is no way of avoiding it, wherever you are.

Frankly, I find the cultural Christmas a bit of a pain. The main problem for me is that it starts in October. Then there is all sorts of goo-gorey-ness, trivia and general wasteful marketing of things which destroy the planet's resources for little benefit.

For me, this time of year is a time for reflecting. And for me this year it has definitely been about reflecting on those less well off than myself. Less well off in every sense, including health, fitness, wealth and also for those who feel excluded from society. This can be a very lonely and frightening time for many people.

Have a good time and be like me - do not over-indulge.
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Thanks to several people for your emails, posts and comments over the air.

Particularly motivating were messages from Thomas OV3T and Geoff G0LUJ.

I think I have done my home-spun noise solutions to death on this blog, be here goes again.

Thomas replied to an earlier post about WSJT-X. I could not get WSJT-X to work well with my computers, and especially if I tried to use multiple instances of the software. I had not really written that piece very well, as it looked like I could not get multiple instances to work, but actually what I meant to say was that my computers are not able to process MSK quickly enough - other WSJT-X modes are fine. This seems to apply particularly to AMD processors.

As Thomas has raised the subject, I set to thinking more about it. I certainly do have a faster computer. Although it also has an AMD processor, it is an eight core and quite fast. The problem with it is that it makes a lot of noise, especially on the 2 metre band. In the past I have tried and rejected it as it simply swamps my 2m receiver with hash.

Geoff has also been tackling noise. As well as everything else, he has started a blog - here. Reading Geoff's thoughts set me to work. I decided to install the faster computer and just deal with the noise.

I do like a challenge. I have looked at this machine several times, and each time it produced enough noise to render 2m impossible to use. Here we go again.

After a lot of tinkering, including disconnecting every peripheral device, and removing most of the plug-in boards, I drew a blank. The faster computer was adding a good 20dB to the noise. Then I tried disconnecting the case fans - and the S-meter fell by 12dB.

The rogue computer case fan

There are two case fans, the one at the front does not seem so bad but I have left it disconnected for now. The rear one was making a nasty chopping noise and I  have removed it. It had been running continuously while the PC was running. I have replaced it with a new Arctic Fan Pro temperature controlled fan with a screened lead. The speed varies with the temperature detected by the fan's temperature sensor.

Moving on I found that most of the remaining noise seemed to be coming from the SVGA display lead - which oddly enough was on the previous computer too. Much more tinkering, with moving over to a DVI lead, eventually proved that the noise was coming principally straight off the Asus display board's plugs. So out came the display board and it was swapped with the one on my "Office" computer (which has an Intel processor and which runs only the IC-7300). The Office computer has an on-board display driver and, while it was not quite as good as the separate board, it can manage without a dedicated display board for now.

The dusty rogue display board (with original fitted fan).

This Asus display board is one of two I have - both the same model but the later one came without a fan. It just has a bigger heat sink and the label "High EMC Protection". The one I swapped over is a cheap generic one with no fan and it seems quiet. I do have one application where the fan-equipped board is useful because it has a low profile form factor and can fit in smaller PC boxes. It is banished from the shack though.

The result was another drop of 6dB on the S-meter. With a more normal amount of pre-amplification than I regularly use the S meter is at zero all the time, unless there is a signal on 2m SSB, which is a rare thing these days.

So I am almost there. I can still detect on 2m if this faster computer is in use. The difference is now small enough to work people. You can never have perfection.

The faster computer now drives WSJX-X or MSHV on my FT-817, TS-590 and IC-7100. It is vastly better than the slower 4 core computer. Two instances of MSK144 at the highest settings still shortens the trace by about half a second. However, I generally do not use the highest settings, preferring normal decode and FTol set to 100.

Typically I would run WSPR on 10m, and listen on MSK144 on both 2m and 6m. That is perfectly possible now if I use MSHV for 2m.

The point of all this is to reinforce the idea I put forward in previous postings. The solution to most of my noise problems lies in the shack. Sure, at Christmas there is a lot of noise from down the street, where one house is covered with flashing LED icicles. Most of this internal noise can be cured, and after Christmas I hope the festive lights will come down.

A basic desk top PC has a box which forms a large Faraday cage. This is pretty effective at keeping noise inside the case. It is the cables and plugs that seem to let the noise out. The case fan is beside several holes but I think that the reason for that problem was simple - it was just awfully noisy. And the display board was connected to a long cable to carry its fan noise out of the box.

Although the computer case is fairly effective, the front USB sockets, the front audio sockets and any fans mounted in the front will be fed by cables passing outside the metal case. The sockets are usually mounted on a plastic front panel. In my example, the simple twisted pair wires cross the void and feed to the USB sockets. This could be a big problem. Whether it is the sockets or the cable is not clear, but a simple solution is present - I don't use the front sockets unless it is for a very short term hook up.

So I have managed to improve things a bit and avoid buying a better PC by tackling the noise. I have another set of rear USB sockets to fit to the fast computer but I am not sure if it is worth it right now. I have the box nicely sealed up and noise-tight. Maybe I should just leave things as they are.

I am pretty sure that the snag remains that AMD processors (or at least those of my vintage) are not very good at handling WSJT-X. I doubt if this is a plot, but probably WSJT-X was designed to work on Intels simply because those designing it used Intels. And they probably did not do much with two instances of MSK144. Anyway, I have saved a few bob here by silencing and using an otherwise good computer.
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There is not much to report on the radio front as I have been pretty busy with other things. However there have been a few good Es openings on 10m, associated with increased solar activity. I will not go into all the details, but here is one example

28Mhz Es spots on WSPR on 9 December 2017

There is no doubt that these openings are limited geographically (though 10m WSPR coverage is not well spread out in Europe so it is difficult to be sure). They are also usually short. I enjoy them though.

There was also a 6m Es event which did not extend beyond Central Europe to reach me. This was not associated with any solar activity that I could find and I think this was a "Christmas Es" event. There may be more - it is worth watching 6m from now until the middle of January. Christmas Es events can be very good indeed, if you can catch them.

I continue to use 4m meteor scatter regularly. My contact tally with Henning, OZ1JXY, has now reached 70 on meteor scatter alone, which proves that this is a really effective day-to-day method of propagation. Then again, a nice contact with Fred, G4BWP, adds another station to the list I have worked via Es, aurora, tropo and meteor scatter, on SSB, CW and data. That list, of multiple contacts in multiple modes via multiple propagation methods continues to grow, showing how many aspects of this hobby are available.

Thanks to both Richard GI4DOH and David GM4JJJ for alerting me to an article in QST about Es. I have to say that this was one of the least scientifically sensible articles I have read for some time (back in fact to the very dodgy ideas about jet streams). For any theory to stand up it needs to show a mechanism causes the event, not is merely vaguely associated with it. This latest article was (mostly) very wide of the mark.

For some reason I do not understand, people are perfectly happy to associate the variabilities in the D and F layer with solar events and the diurnal and solar cycles. The same goes for E-layer events in general. But when it comes to Sporadic E there seems to be a need to associate those events with storms and winds. Here's a clue which they might like to follow up before charging into print with their scrappy ideas - storms and winds are down here, the Sporadic E is 100km up in the sky. And there is another ionised layer (the D layer) to pass through on the way.

Also, the absence or presence of an amateur signal has got more to do with whether there is anybody there to send it than anything else. An elaborate explanation of why I hear more Es to the South East than to the South West could be worked out, but then in one direction I have Italy, and in the other direction I have the Atlantic Ocean. I suspect that there are more operators in Italy than in the middle of the Atlantic. Something to think about?

It is a pity because that QST article did touch on a few important issues which get very little attention - for example variation in the Earth's magnetic field. This is often associated (carefully chosen word there) with variations in the Earth's crust, especially at Earthquake and subduction zones. Someone comparing the magnetic field and the incidence of Es might be able to write an interesting article. But any such article would need to take account of the fact that more than half the world's amateurs do not have access to 6m, and that activity in the countries which do have the band varies enormously.

Also, and here is a thing somebody should consider before someone rushes into print - sometimes it is night and those funny foreign people don't come on so much after they go to bed, even when it is daytime here.

I have been reading some interesting stuff. Research has suggested a link between thunderstorms on Earth and cosmic ray bursts. This needs more investigation, but you can see that the chain of ionisation down through the ionosphere could indeed bring many lower energy particles down into the weather zone and have some effect.

Even more surprising was a piece on the BBC "Inside Science" programme which explained that two independent groups of researchers had found evidence of atom splitting in high-intensity thunderstorms. These strong storms are rare, but the effect may be similar but weaker in everyday thunder storms. They found not only that the strong electric fields and currents cause ionisation (which we knew from the lightening), but also they could be strong enough to create X-Rays and Gamma rays, which in turn create isotopes of surrounding atmospheric atoms. Indeed, not only did this split atoms, but they found evidence of positrons. Anti-matter made in thunderstorms (admittedly very powerful storms).

Phew. Long lasting isotopes (with half-lives in the tens of minutes) and anti-matter created by nature on Earth. These storm events are very powerful so perhaps I should not be surprised, but I am.

All this is pretty amazing stuff. I have grave doubts about the simple linkages suggested by people between weather and Sporadic E. OK, they might share the same basic source, such as the first research into cosmic rays suggests (though this is still fairly far-fetched). But the second piece of research prompts me to accept that another linkage is possible, that thunderstorms could create high energy particles which could well travel towards the ionosphere. Maybe in less energetic storms this could play a part too. I doubt it.

I am not about to rush off and write an article which links the variation in Es events to thunderstorms, based on these ideas. That is because they probably don't cause Es. I do wish that we were not regularly subjected to the "I got up one summer, looked out at the roses, and realised that rose flowering and Es are related"-type articles. Yes, roses and Es share the times of their incidence. But that does not mean they are linked by the rose perfume rising up to the E layer and activating the ions.

Hey, maybe I could get some payment for an article based on just that.

The way that science progresses is for people to be proved wrong when better theories appear. I may be proved wrong. That is fine with me. But where are those better theories? All I see are ideas that might come from the brain of Professor Frink in The Simpsons.
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Again, please enjoy your Christmas.

Activity is usually up around Christmas. Must be due to the roses.

73

Jim

Using aurora warnings to predict Es, and more on noise reduction.

November is another time of the year when, in addition to nice meteor scatter contacts, I can find Es openings by using the data available for aurora watchers.

There is nothing especially new about this, I do it every year. The first step in the process is to forget the constant barrage from amateurs who have "found the link" between Es and the weather, the sea temperature, Alpine lightening and so forth, and return to the more generally accepted view that the ionosphere is affected principally by events on the Sun. Particles (and radiation) from the Sun have a major influence on the ionosphere.

I hasten to point out that the weather does have some influence on Es, as to some extent wind shear is a factor. But none of the theories put forward so far seems to work for me in a predictive sense. I can do without theories which look backwards and explain how the events occur after they have happened. This is interesting but not very helpful when you are trying to fit radio into your already busy life. I like something that tells me when something is likely to happen (in the future!).

When there are strong events on the Sun this often produces auroral propagation here, and I enjoy that. But less powerful events also make for nice Es which most people miss. At one time I just stayed tuned to 144MHz and listened for aurora, now I enjoy contacts on 10m and 6m Es while waiting for any possible aurora. Often there is no aurora here anyway. So my time is not wasted.

November produced a few of these events, as it often does. It is not helpful to look at sunspot activity as a predictor here. There is some vague link - auroral activity is said to peak two years or so after a "solar maximum". Fortunately for mankind the Sun is always active and many very good events can occur at any stage of the solar cycle. There are mini-eruptions, and a huge variety of disturbances and small irregularities on the Sun which have an affect here.

So I look for raised solar wind speed predictions. The polarity of the arriving material seems to have little influence. Some very nice Es openings have occurred when the "Bz component" (an element of the Solar wind's three-dimensional magnetic fields which tends to encourage radio auroras when negative) is either positive or negative. Sometimes I wonder if positive Bz is not better for Es and worse for radio aurora, but I have no strong evidence to make a conclusion about that.

Anyway, enough waffle, what happened? After rambling in my last post on 24 November I decided to try out 6m Es. I could see that "space weather" was disturbed, with high solar wind speed. The "normal state" for the GOES low energy Xray flux level (the lower blue graph) is so low that it often disappears off the bottom of the logarithmic chart. However, in the period 22 to 24 November it was high and variable. This is the sort of thing which makes me look for Es ...

GOES Xray flux levels as shown on Solarham, period 22 - 25 November 2017

I was getting good results on 10m WSPR ...

10m WPSR spots at GM4FVM 24 November 2017.

So I reckoned that the best propagation would be to the South, given the 10m results and the fact that what solar energy there is at this time of year is concentrated towards the equator. Any slight improvement to that background ionisation by the raised Xray levels and solar wind might cause a 6m opening.

At 13:30 I worked EA5/G3XGS on 6m using FT8.

This was the only contact I had but it proved that the aurora warning was fairly effective in predicting Es. Not every contact is reported on DX Maps and no doubt if there had been other stations operational on the generally North/South axis I might have worked more.

The 10m opening continued for another hour or so.

These openings are frequently weak and often short, but they do prove that there is life on 10m, and sometimes even 6m, outside the enthusiastically supported Summer season.

With another warning of possible auroral activity on 1 and 2 December I tried again. The event proved to be too weak for auroral work here, with the wind speed over 400 but less than 500, and the Bz negative but in the range 2 to 5.

Solarham data 1 December 2017

Just the formula for Winter Es 10m action ...

10m WPSR spots at GM4FVM on 1 December 2017

Nothing got high enough to worry anybody on 6m Es, and anyway, most 6m activity has switched to MSK144 for meteor scatter events (which is another subject, but covered in my last posting). Still, on 2 December the 10m event continued.

10m WPSR spots at GM4FVM on 2 December 2017

Maybe not as productive as the day before, but still hardly "the band is closed" as many think.

Sometimes I think that non-auroral events give me more fun that the full-blown ion-stripping magnetic blast of the Northern Lights at their most majestic. Anyway, a big event which causes auroral propagation often produces Es as it gets weaker, which all seems to be the same mechanism to me.

Anyway, more solar fireworks are predicted for around 4 January (possibility of Au and Es) due to several coronal holes, and this is a period which could coincide with raised barometric pressure (possibility of tropo) and a combination of weak patterns of meteor shower activity (possibility of meteor propagation). We shall see if this grand conjunction comes to anything, but a bit of 10m Es would satisfy me; anything more is a bonus.

Coronal Holes as detailed by Solarham on 2 December - effects expected around 4 December

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I have talked to couple of amateurs who have complained about man-made radio noise in their localities, but when I asked them if they had checked their own noise generation they replied that they had not.

It is very easy to blame everyone around you without checking your own contribution.

When it comes to noise the Inverse Square Law is our friend. Anything twice the distance from me is one quarter of the power here. So anything generated "down the street" is likely to be weak. But the converse applies - anything generated in our own home is likely to be very strong indeed.

As with so many pet subjects, I have been banging on about this for years. The thing is, the task is never-ending. I can blame Mrs FVM's laptop. The power supply is surrounded by ferrites but the thing radiates directly. The upside of this is that Mrs FVM is more likely to respond to a request to turn the thing off than my neighbours.

I recently bought a new laptop myself. It has an i5 processor and a large quantity of nice fast RAM. Well it is not exactly new. It was second hand from eBay, quite a bit less than £150, and it came without a power supply. Bargains like this often come from company liquidations, one-off exercises and the like. I myself was involved with a one-off project where 1500 people were loaned lap tops for a three month period. The computers were then collected back up and appeared on the "almost new" market. Mine has a slight screen defect, but it was much less than a quarter of the new price.

Anyway, I also ordered a branded "original" power supply from an unknown site on eBay. In the past I have ordered these and they turned out to be unbranded copies which poured out interference, but the seller had always mysteriously disappeared when I tried to complain. This time it didn't even turn up and I got a refund. I run the "new" laptop on a multi voltage, multi plug general purpose PSU which make almost no noise. Anyway, the one that I had refunded turned up weeks later. Although it is branded it make a dreadful racket. Is it a fake? Who knows.

This story just reinforces my thoughts that you cannot expect to be noise-free. My own computers and screen make some noise and I try to minimise that. My central heating boiler makes a noise on 10m which affects the received signal on my FT-817 but not on my IC-7100. If you look at the design of various rigs some will be more inclined to suffer from noise than others, and as usual the degree of linearity will play a part (in both the susceptibility to noise and the price of the rig).

Noise is unavoidable but it is not incapable of being reduced. Regular readers will have read about my efforts with LED versus fluorescent lights, BT modems versus generic brands, cooker hood power supplies, USB leads of all sorts ... the process never ends. Nor should it. New devices appear in the FVM household regularly and there is always a dB or two to save. I don't automatically blame the neighbours because experience has shown me that the latest noise is ALMOST ALWAYS arising from within the FVM demesne.

For a while I have been wrestling with setting up some sort of network for the shack and office computers. This was wi-fi based but keeping the wi-fi dongles going despite Windows cheerful but destructive updates finally beat me. I also found it hard to keep the USB cables quiet. Several computers in a room should be wired for internet connectivity, or so my out of date thinking goes. The problem was that my last (also second hand) computer produced dreadful noise when connected to an ethernet connection. That computer has been stripped down to the mother board, fitted with a new processor, got up with new peripherals and power supply, and mounted in a new box. So everything was approved noise free except the one thing that changed, the motherboard.

Having left it on wi-fi for months while I cogitated on this issue, I decided that the ethernet socket must be at fault. After all, that was the story behind the BT modem. I bought a USB3.0 to ethernet link to allow the internet access to reach the computer via  a different route and first trials suggested that this made no difference.

After allowing all this to mature a bit further, I decided to move the internet access point closer to the computer and use a better quality ethernet cable. I chose a CAT 6 cable, well screened with metallised plugs and only 500mm long. This replaced a CAT 5 with plastic plugs which was 1.5m long. The result was remarkable. Not complete silence, but manageable.

Not all ethernet cables are the same: Left screened CAT6 with metal plug, right regular CAT5 with plastic plug.

I am beginning to wonder if all ethernet plugs and sockets are suspect. Next project is to screen the USB3 to ethernet converter using the "Bacofoil" method to see how that works.

It is worth it. I now have both radio computers linked via a wired connection which is not only quicker, it allows ShareMouse to work perfectly and allow me to use just one keyboard and mouse.

New sources of interference pop up all the time. Just moving a cable can cause problems. At the extreme I have turned off the house mains and run the radio on battery power to see if it was coming from within this house (in that case it was). A simple test is to listen to the radio while you turn off the suspect device and unplug the power supply. Most computers create some hash but some if it can be tolerable.

We have a general rule in this house the every device should be turned off at the mains if not in use. This extends to two "smart" TV devices. The policy also saves on the electricity bill. Simple ferrite filters work remarkably well. I have recently invested in a commercial mains filter as I have no other protection against common mode interference entering the rig power supplies via the mains. I doubt if this is a major issue but it seems worth being able to test it. And so the battle continues.

Cross Country Wireless mains filter - still being evaluated

I guess that I may yet be affected by the sort of over-powering interference which has put other amateurs off the air. However, it will not happen until I have tried my best to carry on using my own best efforts and a few simple precautions.

73

Jim

GM4FVM