The Growing Impact of Environmental Radio Noise
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- Опубліковано 27 вер 2024
- The quest for low cost, high efficiency power conversion has a downside, radio frequency interference or more specifically QRM, noise from man-made sources. Broadcast engineer Steve Johnston has worked in the commercial, public and governmental broadcast sectors and has shares his insights into the forces that created the growing problem of QRM.
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![Stop RF "Radio Frequency" Interference! [Ways To Solve Noise Issues]](/img/n.gif)
The noise on HF is absolutely terrible these days. Mostly cheap chunk from amazon/temu. If you report it, it goes away and comes back with a different gibberish 'brand name' :(
Well they gonna have to do something at some point. Or we'll collectively be thrown back to Pre-Industrial levels of communication and orientation!
We outlawed spark-gap transmitters nearly 100 years ago. We then eliminated regenerative feedback receivers as they too could cause interference. We took pride in our appliances that had rectifiers in the power supplies, and designed them with bypass capacitors across the diodes to quench harmonics that could be radiated. Even our cars with spark plug wires were designed with increased resistance and along with resistor type spark plugs did a good job at keeping that spark in the engine and not becoming a "buzz" you could hear on your radio at home when the guy drove down your street.
So WHY then are we not clamping down on SMPS, noisy inverters, cracked or carbon tracked insulators on our electric grid, and lastly the controllers on many EV vehicles?
Why did car manufacturers want to eliminate AM radios in their new models? Noise is cumulative. Until and unless we DEMAND standards and have them enforced, the problem will continue to grow. I yield my time back. 73
Agree, I have had many times tracked down noise in my own home to these simple products that can destroy any sense of quiet on the air.
@@WECB640 why? because the society largely doesn't care about radio reception anymore. For manufacturers, implementing additional RFI suppression circuits is just not worth it.
Would be nice if the emission standards would enforced
ATX power supplies for the PC industry often had the torodial rfi trap omitted inside them. It was shown on the PCB silkscreen but it was jumpered across.
Boy, did you hit the nail on the head!!!!
When I was chief engineer of a small cable system, my number one way to keep things running is noise ingress and egress on the plant. Also the state cable commission was very diligent in following best and FCC rules and practices.
Today switching power supplies are my biggest challenge even in my home. Second is the led light bulbs used in my home, they can be just as noisy!!! LED is good for cost of power, when you can reduce the kWh of light usage up to 90%. But the question, is it worth it!!! Go back to 100 watt light bulbs vs 9-13 watts??? Get the FCC to enforce its rules and regulations???
Personally the FCC needs to step up to the plate and do its job!!!
73’s
DE N2JYG
Agree. I added better grounding to the house, replaced the breaker panel, got rid of most dimmers, and things are better.I have one light that can't be on if listening to A M. Daughter left an Apple clone charger here, I found it was horrible. A hammer took care of that.
Switch modes can be terrible.
I got into amateur radio and SWL in the late 70's when I was a teenager. I have seen the steady increase in RFI over the years, which of coarse has made the radio hobby less enjoyable!!
Of all the sources you listed I think Switching mode power supplies and computers are the biggest pain. LED or CFL lights are a close second. Battery chargers and TVs are probably my third worse RFI producers.
I have a couple newer radios equiped with USB ports to charge the batteries but unfortunately I have found that every USB power source I have creates RFI and therefore the radios become basically deaf with USB connected!
I have found the sources of RFI using a portable AM receiver. I switch off all my house breakers first because like you said, a lot of devices are active as long as they are plugged in to an outlet. I once found that I was getting RFI from my neighbor's ELECTRIC BLANKET! The noise being coupled from their home into mine via wires that ran over both trailers. They got a new blanket!
I worked for a couple manufacturers of communication and test equipment and I agree with what your sources in electronics manufacturing told you.
How much of this noise because of our modern ac/dc adaptor over the classic internal power supply ?
internal VS external power supplies is not the issue:much of the problem is switch-mode power supplies VS linear power supplies.
This is particularly true on AM and SW.
@@m.k.8158 It depends on general noise level around. Possibly in not noise place it can be issue but in high noise any switchng it off may not make noticeable change
I'm so glad you posted this. It needs to be said. Sad that the feds (FCC) don't care.
Go Navy,operation specialist radar & radio U.S.S. Ticonderoga CG-47,First Aegis Class 1981-1985. SPY1A so awsome......❤
Excellent ! It is not difficult for an individual to actually prove the validity of this . Thanks for sharing !
I don't think you mentioned it, they aren't popular everywhere, but most, if not all series string type rooftop solar systems are *extremely* noisy during the day. I can hear neigbors up to a half mile away. Driving thru populated areas is just a cacophony of broadband solar system noise. It's so bad here in CA, I pretty much gave up on HF many years ago. My own micro inverter based solar system is dead quiet.
I should have mentioned in my presentation that I was surprised to find so much radio noise here on Kauai - much of it from solar power systems on the roofs of the houses. I can go portable into parks and find quiet HF locations, but my neighborhood and other towns are quite noisy across HF.
Many years ago I went on a holiday in my caravan (Australia), up country I went into a supermarket and noticed these cheap 12V LED lamps (downlight), these were just coming out and were mostly somewhat expensive, this one was not, so of course I bought one and took it back to my campsite.
I basically knocked out every radio band I had, AM broadcast, Digital TV, UHF two-way.... nothing worked.
The lamp had a switch-mode supply feeding the square wave straight into the LED element with absolutely no filtering what so ever.
Some electric vehicles produce strong EMI in the shortwave bands. My vertical antenna is about 150 ft from a road. A few times per hour the broadband noise level, especially near 7 and 21 Mhz, goes up to about S9+10dB for 30 sec as an electric vehicle goes by. Some time I will have to watch the road to see which EVs are worst. I think I am also hearing noise from some EV chargers in the neighborhood.
Thank you very much, great presentation. Comes down to money..money to manufacture the equipment properly, money to fund research and official intervention, and so on...and as you so wisely pointed out, few know about this at all...I'm a ham, I have untold fortunes spent in ferrite cores, proper supplies and shielding, hell, I even copper taped the entire electronic cavities of all my electric guitars...
There is probably work that can be done to corollary between Electrical test and tag and the IT test teams in most company environments. If they can to an agreed Test and Tag with a boxed emissions test or thru DC output test, (barrier cap failure) that might be helpful to swat this mess inside of the safety loop. Might be an excellent opertinity for a smart instrumentation company to make a windfall???
Bluetooth is very affected by noise, sometimes it disconnects near a mobile phone mast
Thank you
I'm on off grid solar power and one of the downsides of it running pure sine wave inverters is that there's quite a bit of RF interference with a 60 HZ repetitive component. It pretty much wipes out the 160 m band and 75 m is very noisy. I've had to invest hundreds of dollars into clamp on type 31 ferrite chokes to put all over the wiring going in and out of the inverters. I've knocked the noise down about 25 DB so at least I can listen to some radio.
Have you tried using 75 material chokes for common mode currents suppression on low HF bands?
@@samgrieg I've had good success with 43 as well
@@samgrieg No, I've been buying mix 31 cores as they have high reactance at HF and lower frequencies. What are the characteristics of mix 75?
I should have mentioned in my presentation that I was surprised to find so much radio noise here on Kauai - much of it from solar power systems on the roofs of the houses. I can go portable into parks and find quiet HF locations, but my neighborhood and other towns are quite noisy across HF.
@@steve1919 It only gets worse, with many electric vehicles coming online these days. But solar has saved me thousands of dollars on electric bills. I can live with a little RFI, knowing I saved $12,000 on electricity this year.
Sounds like lots of free energy 😂
very interesting... ev's...nice ! who knew ? what about ev charging stations ?
I believe I am dealing with a noise problem from a nearby traffic light system. It is absolutely repetitive - you can set your watch by it. It cycles over several minutes and repeats over and over. It is very broadband from around 10-30 MHz. Driving me nuts!
When I started as a two way tech in the 70s intermodulation interference was already a problem. It has been cleaned up a little now that radio sites require isolators and cavities and double shielded coax but the noise floor is still rising everywhere. It just shows that when you knock the RFI down by 20dB but multiply the number of sources by a hundred you end up back where you started.
Yes, being a radio listener and operator
since 1960, I too have seen the noise
imcreased over the years worsening. 😮
The only time I can hear SW is when the power is off everywhere. The power company did an investigation and they said there weren't any problems.
Many years ago I was experiencing random RFI and it was starting to drive me nuts. This was in a trailer park and one night I was outside shooting the breeze with a neighbor when I happened to see a spark up on the power pole that served our trailers. It was kinda hard to see because of the streetlight but it would randomly flicker. My neighbor confirmed it. I called the power company the following day and they replaced a bad insulator that was arcing! 😁
@@RichNotWealthy Congratulations. In 99% noting can be done except long enough antenna in minimum 10m distance from main source of noise which is usualy whole building. I experienced the same - I was disturbed by brakes in mains energy to building but at such time listening to battery SW radio even in city is amazing