Rising RF Noise Levels - IARU submits paper to CISPR

EMC problems from various forms of power electronics are being addressed in an increasing rate as solar powered systems spread among home-owners and some industrial businesses.

The problem has been brought to attention to the Swedish military communications and aviation safety communities by the work at the Aviation Safety Authority by SM5KYH, the Electrical Safety Authority by SM4UKE (CISPR sub-committee member) and at the Defence Research Establishment. Some of the early findings were summarised in a paper presented at the Nordic HF Conference HF19, of which I am one of the organisers, "Interference impact from solar-panel systems on HF communications".

Generally speaking, "weak-signal" spectrum users have ended up in a difficult situation. The unprecedented and largely unforeseen problem of amalgamating large numbers of emitters, which may fulfill the requirements in isolation, has created an EMI situation far beyond anything previously experienced.

It has also crept upwards in frequency, so just recently has interference been reported to both 400 MHz public safety communications and 800/900 MHz cellular services.

A very likely outcome of this, if not properly resolved before, are law-suits against the owners of the solar power installations for infringement of the rights for interference-free use of spectrum, which are set out by law in the case of public and transportation safety, and by contract for the cellular operators that have paid billions at spectrum auctions in order to get spectrum access.

If major interference mitigation schemes are launched under the threat of having to remove the installations if interference continues, radio amateurs may also benefit from this.

However, as the current legal situation is undecided, anything may happen.
"Green Energy" has a lot of political support, and politicians are notoriously ignorant about engineering matters.

Maybe the aviation safety aspect could have some leverage, as members of the political class mostly are "frequent fliers".

"Time will tell"

73/
Karl-Arne
SM0AOM

 

Especially ham radio operators are the first 'victims' of the RFI generated by the plethora of all kind of devices flooding the market. No matter what the EMC standards do, as these devices increase in number, it means that a standard today is ineffective tomorrow (to some extend), considering especially the long-term (several years...) process of revising a standard.
Additionally, the laboratory testing methods prescribed within EMC standards consider the emissions (radiated or conducted) typically from a single product, e.g. what one power supply generates alone. The reality is much worse when someone considers the cumulative EMI effect of multiple electrical/electronic devices operating all together in the same environment. But, EMC standards can only do that much and there is no blame there.
On the other hand good EMC design is an expensive process and manufacturers do their best to minimize this effort i.e. cost, at least on non critically safety products. Our radios are predominantly analogue receivers with some digital post-processing within, so they can't eliminate effectively all these RFI pollutants.
I have 3 stations, two within a city and one in a remote village location. You can't imagine the difference of the noise levels I see on the HF bands: man made RF noise within cities will sooner or later make our HF radios deaf (digital modes will die last...), 73, SV1QZS

 

No radio can recover a signal buried in fully uncorrelated white noise
as the noise power is proportional to detection bandwidth.

When the bandwidth is decreased below the value needed to create a "signal matched filter", the message content of the signal will be more and more destroyed.

Noise reduction algorithms may help somewhat if the spectral components of the EMI are not fully uncorrelated, or some other property of the wanted signal can be exploited, such as medium term time variation.

73/
Karl-Arne
SM0AOM
73/

 

Note to Moderator: The following is not an attempt to bring politics into the discussion. But, there are some current Governmental happenings that may have a bearing on the situation being discussed in this thread and those happenings should at least be known.

When it became apparent that the Covid-19 pandemic was going to have deleterious effect on the economy the U.S. Federal Government, in essence, suspended any regulation that 'inhibits economic recovery.'

According to several news sources an order signed last month (May), "directs agencies to consider what sort of deregulatory action they might take that could spur economic growth."

The order directs agency heads to “identify regulatory standards that may inhibit economic recovery,” highlighting that regulations could be permanently or temporarily lifted. As ordered, “Agencies should address this economic emergency by rescinding, modifying, waiving, or providing exemptions from regulations and other requirements that may inhibit economic recovery.”

Such action would be cross cutting, and could range from financial regulations, environmental protections, agricultural guidelines that affect the supply chain, or virtually any regulation from the numerous government agencies that promulgate rules.

The original order was supposed to be a temporary measure, but there are currently some calling for the order to become permanent...

Now, the question is.... Does RFI mitigation 'inhibit economic recovery?' I can see how some large corporations (and other entities) could make the claim that having to comply with the FCC's 'regulatory standards' on RFI might 'inhibit economic recovery.'

IMO this has the potential to become a nightmarish situation (more than it is now) for Hams and other radio enthusiasts.

Dan WQ4G

 

Maybe.

RFI mitigation costs money, and the industry is fighting nail-and-tooth for the EMC requirements to be as loose as possible.

But when the interests of paying or safety related users of spectrum could be endangered, other decision levels come into play.

A good example is public safety communications. Even the most corrupt politician may have an intuitive feeling that a communications failure for, say, fire-brigades or ambulance services may have a direct influence on his own well-being.

Same goes for traffic aviation safety. The plane crash caused by radio interference may be the one in which he becomes a victim.

I am closely following what is currently going on here, partly from a professional interest, and partly from the amateur radio perspective.

Just a month ago, planning permissions for residential solar power installations were revoked by local authorities on the request of the Armed Forces, citing interference potentials.

However, this was appealed to higher court, which reversed the earlier decision, citing individual rights and environmental protection reasons.

It is expected to find this, and similar cases, being taken to higher and higher administrative court levels, finally ending up in a decision by the judicial branch of the Government.

How long this will take, and the final outcomes, is anyone's guess.

Solar energy also has a lot of popular support, and making the installations more expensive may hurt the approval of both local and central politicians.

Judging from forum activity, there is a massive public ignorance about the RFI potentials of the installations, and in case of radio amateur neighbours complaining, they were told to "go away and play with their radios elsewhere".

73/
Karl-Arne
SM0AOM

 

I think we are just going to have to have to except this noise as normal and expect it to get worse over time, as all the older electronics and wall warts get replaced, with these switching supplies. And what about all the new RF devices for short range applications that may have no filtering in them what so ever.

I do think we should try to keep pushing to do something about it. At some point it will be interfering with more paid services, and probably already is. How would the average consumer even know why a signal wasn’t getting threw on a cellphone, or OTA digital TV station not coming in very well that’s only 10 miles away, or why the WiFi on their portable device has a hard time connecting when they are in a certain place even though the signal is strong. Most people would have not one clue what’s going on, and never complain about it. Who are they going to complain to? And what are they going to complain about?

At least for us, we have an idea. I live in the city, plenty of noise here, but I do what I can to make it invisible on the radio. Lots of RF CMC chokes, and a phase noise canceler. I know that’s not a device everyone has, but I think it’s time everybody should get one if they have noise issues. They are a radio life savers. I see some newer SDR radios are coming with this feature and my guess is it will become a standard feature in the future.

Like the interference that NG0G showed on the garage door opener, a phase noise canceler will easily make that kind of noise a thing of the past, like it was never there to be a problem in first place.

I myself had an issue with a plasma TV. Oh I know it’s common knowledge now, but in 2005 when I got one, I had never heard of the problem. 20db over S9 noise on 160, 80, a lot on 40. The phase noise canceler made it disappear like it wasn’t even there to start with. The good thing about these is it doesn’t distort the RX signal like the NB and on the radios.

 

Very true

 

Dan i do agree with you, my background noise is getting higher and higher S10 noise level ! i had installed 2 ground rods one at the tower and the other one near the radio equipment. and also using a filter by "BHI" , In the last 5 years i had noticed the interference level was increasing. Yes i did check all ground connections went around the house unplugging just about everything, i did find "Made in China" equipment adding to my noise level, but now most of the noise level being generated is coming around from my neighbor i tried to track down.

 

This is sometimes why the stuff coming from places like China are 'cheaper.' Because they don't contain the parts necessary for filtering, nor any of the labor to install the parts.

Most of the noise I experience here is Power Line RFI. But, more recently there are other signals starting to show up. There are now so many sources around, some of them quite strong, that it is becoming difficult to discern which one(s) are/is buzzing the radio. And, unless one can identify the exact source of the signal, it becomes impossible to resolve the issue. If one is able to afford it there is equipment available which has the ability to identify the exact source.

But, how does it perform when there are multiple sources of different types of RFI all mixing together?

Dan WQ4G

 

An interesting idea to say the least... I can certainly see how a set up like that would be VERY useful for RFI hunting. And, at $100 it is very affordable.

I'll have to start working on my 'budget request' right away...

Thanks

Dan WQ4G

 

The standalone device I have can only handle one noise source at a time. Fortunately I’ve only had one at a time of any consequence. I’m sure that won’t apply to everyone. As far as the SDR radios that have this function, I cannot say if they can cancel multiple signals at once. I will contact an owner I know that has one, and see what it’s capable of.

 

OTA Digital TV should not be affected by external interference, if it's strong enough to capture the receiver the image is good, if not, there is no image unlike the old analog broadcasts that were subject to flutter from airplanes and snow due to distance from the transmitter site or a marginal antenna, or other sources like universal electric motors, drills, portable power saws etc.

 

Exactly,

That’s why no one would suspect it to be interference from some other device. Just because its DTV doesn’t mean it isn’t, or can’t be interfered with.


OTA digital TV is a blessing for hams. No one would ever know when we are interfering with it. No signs of interference other than losing the signal. No distorted picture and gargled audio like the old days.


I can assure you, as a person that uses only OTA digital TV, it can still be interfered with. I have on occasion, interfered with it using the HF radio on certain bands with the antenna pointing over the house, and my kids Sony PlayStation 3 severally interferes with it, if it is left on when they are not using it, and someone tries to watch the TV. It blocks out nearly all the 30+ channels we get if it’s on.


The PlayStation doesn’t interfere with itself, it uses the HDMI connection for the video, but is sure causes a boat load of RF interference of some kind that the TV receiver sees.

 

[QUOTE = "G0VEO, post: 5495359, member: 12355"] Pour ma part, je ne vois pas la fin de l'afflux mondial massif de déchets électroniques en provenance de Chine, ainsi que les atroces alimentations Wallwart de mauvaise qualité qui accompagnent cette ordure. ..je pense ce que tu
ne sont que la pointe de l'iceberg et, à ce titre, ne feront malheureusement qu'empirer, car la plupart des pays se battent pour maintenir leur économie en vendant ces déchets à quiconque achètera. [/ DEVIS]
Rien n'a fonctionné comme l'assurance du départ concernant le numérique ! En cas de plainte la première réaction des services de contrôle est : qui va payer... cela se retourne contre l'utilisateur !

 

Replying as someone who spent over a decade doing interference hunting professionally: (sorry in advance for the long reply)

This is, of course, very true and unlikely to change. At little bit of on-the-spot education helped a lot.

There are some interferers I could have found with an AM radio and coat hanger, and there are some that needed the six-figure direction finding system. There is a very large price/performance gap between what amateurs and professionals use for interference hunting. My company would love to sell interference hunting instruments and antennas to amateurs, but there is no market due to cost.

Almost all interference is located and resolved by the "victim" without involving the FCC -- even huge companies that have paid (literally) billions of dollars for the exclusive right to certain spectrum do not call the FCC except in very rare cases. The FCC is (unfortunately, in my opinion) very resource-limited.

That is the understatement of the century

This is an excellent point and one that I also bring up constantly when I give presentations, webinars, whitepapers, etc. on interference hunting. My answer (and the answer the FCC will give you) is that it must be harmful interference. If you have sensitive enough instruments (and I do), you will find the world is FULL of signals where they don't belong, but very few of them are harmful.

Everyone who has done (professional) interference hunting sometimes finds an "interferer" (source of RF) in the victim's band, tracks it down and has it turned off, only to learn that the victim is still reporting "interference." Part of the trick to being efficient at interference hunting is learning to recognize that not every signal in your band is an "interferer" and to focus on those signals that have the potential of being harmful interferers.