Tag Archives: QRM

Faulty TV to blame for 18 month broadband outage

Many thanks to SWLing Post contributor, Jeremy, who–in light of our recent discussions about RFI–shares the following news item from the BBC:

The mystery of why an entire village lost its broadband every morning at 7am was solved when engineers discovered an old television was to blame.

An unnamed householder in Aberhosan, Powys, was unaware the old set would emit a signal which would interfere with the entire village’s broadband.

After 18 months engineers began an investigation after a cable replacement programme failed to fix the issue.

The embarrassed householder promised not to use the television again.

The village now has a stable broadband signal.

Openreach engineers were baffled by the continuous problem and it wasn’t until they used a monitoring device that they found the fault.

[…]”Our device picked up a large burst of electrical interference in the village.

“It turned out that at 7am every morning the occupant would switch on their old TV which would, in turn, knock out broadband for the entire village.”

The TV was found to be emitting a single high-level impulse noise (SHINE), which causes electrical interference in other devices.

Mr Jones said the problem has not returned since the fault was identified.[…]

Click here to read the full story at the BBC.

Thank you for sharing this, Jeremy. I can guarantee that if the TV was emitting enough noise to interfere with broadband, it likely also affected the HF, MW, and LW radio bands!

What baffles me is the amount of time it took for the engineers to track down the source in such a small community. A skilled RFI engineer would have likely discovered what was causing the noise by looking at the spectrum analyzer–quite often the signal shape and frequency are indicators. In addition, a little signal “fox hunting” could have proven useful. With that said, noises aren’t always easy to locate and can travel along unexpected paths.

I certainly don’t blame the resident for remaining anonymous!

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Post-storm power outage leads Emilio to find the RFI-spewing source of his problems

Storm with lighteningMany thanks to SWling Post contributor, Emilio Ruiz, who shares the following guest post:


Apprehending an RFI-generating monster!

At the beginning of the year, I was sad because, at home, an awful RFI noise appeared. The next few months the noise increase until S9!!. Day and night my receivers and my feelings were so dampened with this terrific RFI–only the lower Broadcast Band (900 to 540 Khz) was relatively immune to it.

Yesterday, we had a storm and the mains electricity service went off, so I connect a 12 volt battery to my RT-749b military surplus transceiver and the received signals were very clean like the “good old days”.

(Above: Listen W1AW loong distant from my QTH in Chiapas Mexico).

When the power electricity come back on, so did the RFI too!!

(Above: W1AW gone)

Remembering the recently publish post in SWLing Post about RFI, I did some testing by
cutting the electricity to my home (the main switch) and the RFI was gone!! So I discovered the RFI lives in my house–not in the outside wires!!

I put batteries in my old shortwave portable radio and searched (like Ghostbusters) all outlets contacts, one by one, connect and disconnected each device.

And I found the guilty party!

Exhibit A: The Mitzu laptop power supply

On December 2019, the power supply of my son’s laptop broke, so I bought a cheap substitute.

The RFI produced by this little monster could be heard at a distance of about 200 meters from my QTH!!! (Much like an old transmitter spark gap–!)

Even this cheap power supply apparently featured ferrite toroids on the wire but turns out it is fake!! It was only a plastic ball!

Exhibit B: Fake toroids!

The wires were also not shielded. No doubt one of the worst switched-mode power supplies I could have purchased.

Exhibit C: The Mitzu RFI generator wire without shield, only pair wires!

I found a old Acer power supply with same specs and I replaced out the RFI monster one.

And now? The shortwave bands are clean again.

(Video: Testing my Kenwood R-600 rx with Radio Exterior de España… plugging and unplug the Mitzu monster RFI generator).

So I wanted to share what happened to me, so perhaps it can be useful for other SWLing Post blog friends.

Watch these little switched mode power supplies from all devices in your home. Replace them if you detect RFI levels that harms SWLing. Consider disconnect all devices (vampire consumption–or phantom loads) if not in use; the radio waves and electric bill will be grateful to you!


WOW! What a difference! Emilio, that was great investigative work on your part. It’s as if that switching power supply was specifically designed to create RFI! No shield and fake toroids? That’s just criminal in my world! 

Thank you so much for sharing your story. Hopefully, this might encourage others to investigate and apprehend their own local RFI monsters!

(And by the way, Emilio, I love that RT-749b military transceiver!)

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Radio Waves: Digital Broadcasts in South Africa, Cold War Broadcasting in Late Soviet Era, Possible Ban on RFI Producers in Sweden, and Ham Radio on the ISS

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Paul, Michael Bird,  William Lee, Rob PE9PE, and the Southgate ARC for the following tips:


SABA partners with T&A and Sentech to deliver digital radio in SADC (Advanced Television)

The Southern African community will soon enjoy digital audio broadcasts, thanks to an initiative lead by a South African based entity, Thembeka & Associates that has taken the lead in implementing the much anticipated interactive radio solution.

This was announced by the Secretary-General of the Southern African Broadcasting Association, SABA, Mr Cecil Jarurakouje Nguvauva, following the conclusion of initial agreements between the participating entities. Welcoming the digital radio solution to the SADC region, Nguvauva emphasised the need for rural communities to be engaged fully in the developmental agenda of the respective African governments if the planned development is to add value to the lives of the most disadvantaged members of our society.

Chief Executive Officer of Thembeka & Associates, Madam Thembeka Kaka has hailed this initiative a huge success for the continent and a dream come true for her institution. Madam Kaka added that as a member of the National Committee on ICT Chamber Accessible Broadcasting for People Living with Disabilities, she has passionately driven this project for a long while. Madam Kaka added that “Following the announcement of the Policy Directive that has introduced Digital Sound Broadcasting by the South African Minister of Communications & Digital Technologies, Stella Ndabeni-Abrahams in July this year. I have since realised that greater opportunities have emerged for the broadcast industry as a whole. And this initialises an evolution of radio broadcasts going forward,” she stated.

Sentech’s Meyerton Radio Shortwave site in South Africa will carry the Digital Sound Broadcasting Shortwave Transmission from the broadcast centre in Southern Africa to the rest of SADC countries.

For the initial stage, only six countries are earmarked for the coverage, before it is rolled out to the rest of the SADC Region. The targeted countries are Namibia, Botswana, Lesotho, Eswatini, Zambia and South Africa. The rapid deployment is planned to work alongside the existing analogue radio service, which will seamlessly transition to a fully-fledged Digital Radio transmission in SADC. The receivers to be deployed will have the capabilities to receive and transmit both Analogue and Digital radio signal on FM and AM.

The primary purpose of the initiative is for governments and various newsmakers to urgently provide vital information to all citizens, especially the rural, remote and marginalised vulnerable communities. The outbreak of COVID-19 has amplified the need for this undertaking, that has highlighted risk areas in our various communities. Particular emphasis will be given to the following sectors in the respective communities: Education Sector; Health Sector; Socio-Economic factors; Gender issues; Youth & Disability.[]

Listening Out, Listening For, Listening In: Cold War Radio Broadcasting and the Late Soviet Audience (Wiley Online Library)

Abstract

This article interrogates the well?known phenomenon of western broadcasting to the Soviet Union from the little?known vantage point of the audience’s sonic experience and expression. I use the example of the BBC’s main popular music program in the late USSR, Rok posevy, with its remarkable presenter, Seva Novgorodsev, to explore fundamental questions about the who, how, and why of listening to the so?called “enemy voices.” The popularity of Novgorodsev’s show, I argue, is best understood in the context of the Soviet soundscape and, in particular, of longstanding Soviet media practices, including radio jamming and Soviet ideologies of the voice. Novgorodsev’s Rok posevy presented listeners with a powerful alternative sociocultural space, one that promoted models of authority and community very different from Soviet norms and, indeed, antithetical to Soviet norms.[]

Swedish Electrical Safety Agency threatens ban on sale of optimizers (Southgate ARC)

In Sweden the Swedish Electrical Safety Agency may ban the sale of optimizers used in Solar Panel installations due to the high level of RF Pollution they produce

A translation of an SSA post reads:

The Swedish Electrical Safety Agency wants to remove optimizers that spread interference. “It should be easy for the electrician to do the right thing.”

– We want to remove all solar cell products that spread disruption from the market. It should be easy for the electrician to do the right thing, and if you choose CE-marked gadgets and follow the manufacturer’s instructions, the system should be nice, says Martin Gustafsson, who is an inspector in market control at the Swedish Electrical Safety Agency. reports of disturbing solar cells. In addition to radio amateurs such as Anders Ljunggren, the  mobile operator Telia is among those affected . The Swedish Electrical Safety Board has made inspection visits to disturbing facilities, and carried out a market review of optimizers and inverters from eleven different manufacturers.

“They take advantage of a gap in the standard and instead hide behind a general EMC standard.”

The report is not complete yet. However, one of the conclusions is that a number of manufacturers of interfering products have chosen not to use the standard developed for photovoltaic products, but which has not yet been harmonized by the European Commission.

– They use a gap in the standard and instead hide behind a general EMC standard, which does not make any demands on the dc side. This makes our evidentiary situation difficult. But if the disruption problems are not solved, the products can be banned from sale, says Martin Gustafsson.

Text:  Charlotta von Schultz – www.elinstallatoren.se

Thank you SM5TJH / Janne for the information
Source SSA https://tinyurl.com/SwedenSSA

New Ham Radio Onboard The ISS Is On The Air (K0LWC Blog)

Ham Radio operators have enjoyed making contact with the ISS for many years. The holy grail has always been talking to ISS astronauts on FM simplex (145.800) — but those can be rare chance encounters. Ham radio operators have also enjoyed slow-scan television (SSTV) broadcasts and APRS packet radio via the ISS digipeater. Now we get to work the world’s most expensive FM repeater thanks to the new InterOperable Radio System (IORS) installed on the ISS.

The InterOperable Radio System (IORS) replaces an ancient Ericsson radio system and packet module that were certified for spaceflight over two decades ago. The 5 watt HT that was aboard the ISS was getting worn out after many years of use. The Ericsson radio looks like something from a 1990s episode of Cops.

The new IORS was launched from Kennedy Space Center on March 6, 2020 onboard the SpaceX CRS-20 resupply mission. It consists of a custom space-modified Kenwood D710GA transceiver and an ARISS-developed multi-voltage power supply. The equipment was installed by NASA astronaut Chris Cassidy (KF5KDR).

New Kenwood D710G ‘Space Flight Edition’

The radio now being used is a Kenwood D710G and was engineered specifically for space flight. JVCKENWOOD USA and the ARISS worked closely to modify the D710G. The upgrades were performed by JVCKENWOOD and include:

  • Output power is hardware limited to 25 watts for the safety of the International Space Station
  • Custom firmware and menus tailored for operation onboard the ISS.
  • Higher output/high-reliability fan to allow continuous repeater operation.

Continuous fan operation is an important feature in space for the reliability of the radio. There is no convection in microgravity, so all heat-generating components need to be cooled by moving air or conduction. If the radio burns up, there isn’t a Ham Radio Outlet down the street to grab parts.[Continue reading the the full article at K0LWC’s blog…]


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QRM-busting: Rob’s practical approach to tackling unwanted radio noise

Our good friend Rob Wagner (VK3BVW) over at the  Mount Evelyn DX Report has posted an excellent article on how to deal with man-made radio interference (QRM/RFI) in our homes and neighborhoods. This has been a frequent topic here on the SWLing Post (indeed, as recently as Thursday).

I’ve copied an excerpt from his article below, but I highly recommend reading his entire post which includes practical ways you can investigate and mitigate RFI within your home and neighborhood:

Mount Evelyn is a semi-urban, semi-rural location, about 45 kilometres east of Melbourne, the southeastern part of Australia. When we retired eight years ago to this lovely mountain region known as the Yarra Ranges, noise levels on the shortwave bands were quite manageable. At times, it might rise to perhaps an S3, but hanging a variety of antennas cut for a mix of bands and erected in different directions certainly allowed for some flexibility and control over the local man-made noise.

Previously, we lived in a highly urbanized environment where 24-hour S9 noise levels prohibited any SWL or Ham activity from home. But moving to more spacious living at Mount Evelyn allowed me to drag out the radios, string up those wire antennas and really enjoy again the hobby that was such a part of my youth.

But over the past 12 months, I have noticed an increase in local man-made noise around here. The level of general electrical hash on the bands has increased markedly. At certain times of the day, the S-meter is rising to between 5 and 7. And it is not always predictable when the noise levels will rise and fall.

A few weeks ago, the local electric company decided to do a major overhaul of some power poles and wires in an area not far from here. So, the entire region was without power for about seven hours. Fantastic, I thought! I’ll hook up the Yaesu FTDX3000 to the 12v sealed lead acid battery and do some daytime DXing right here in the shack in a totally noise-free environment. Once the lights went off, I fired up the rig and tuned the bands in search of weak signal DX delights.

Err….well, not to be! Indeed, the results were somewhat underwhelming! It was disappointing just how much man-made interference was evident on the shortwave bands, even though such a large area around Mount Evelyn was without power. The hash was still registering a steady 3 on the S-meter. Certainly, it was better than when the mains power is in regular operation. But in the past, when the power had been off, the noise dropped right away, and battery-powered DXing from the radio shack was a real pleasure. But alas, not on this occasion!

So, I began thinking about why this was so. What is going on here?[…]

Click here to read the full article at The Mount Evelyn DX Report. 

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Can’t receive anything on your new shortwave radio–? Read this.

This morning, I received a question from Andrew, an SWLing Post reader in the UK.  Andrew writes:

May I ask a question please? I am very much a newbie to this. I am not really interested in FM, but I would like to listen to international stations on SW, utilities stations, amateur broadcasts and if possible, local airports, aircraft on air band.

I have just purchased a Tecsun PL-680 and have tried it inside my home with the telescopic and wire aerial that came with it, plugged into the antenna port and clipped to a point near the ceiling. All inside the house and the wire aerial did improve the reception, but I get hardly and channels either during the day or night.

Grateful for your detailed advice on what I need to do exactly to improve the number of stations I can receive.

Kind regards
Andrew

Thank you for your question, Andrew, and I hope you don’t mind that I share it here on the SWLing Post as I receive this question so frequently from new shortwave radio enthusiasts.

Of course, a number of things could be affecting your shortwave radio reception and there is, of course, the possibility the receiver is faulty–however, this is very unlikely. Let’s talk about what is most likely the culprit:

Radio Frequency Interference (RFI)

RFI is quite often the elephant in the listening room. It’s not always immediately obvious–especially if you’re new to shortwave listening.

RFI (also known as QRM) is radio noise that is created locally and often concentrated in our homes and neighborhoods. RFI deafens our shortwave radios by overwhelming the receiver with strong spurious signals. Even if you can’t hear the noise, it could still be overwhelming your receiver from a different portion of the band.

RFI can emanate from most any modern electronic or digital device in your home: televisions, power supplies, dimmer switches, smart appliances, and even computer hard drives. Honestly, most any device could be the culprit.

These “Wall Wart” type adapters can create a lot of RFI

RFI can also be caused by power line noises outdoors which have a much larger noise footprint and typically require intervention from your local utilities company/municipality.

In all likelihood, though, it’s a noise inside your home.

There’s a quick way to determine if RFI is the culprit:

Take your radio outdoors, away from the noise

Depending on where you live, this might only require walking with your radio to the far end of your garden/yard, or it might require hopping in your car and visiting a local park. The idea is to find a spot far removed from houses and buildings, outdoor lighting, and even power lines if possible.

Once you find a listening spot, turn on your portable and tune through some of the popular shortwave radio bands.

If in the late afternoon or evening, I like tuning through either the 31 meter band (9,400–9,900 kHz), 41 meter band (7,200–7,450 kHz) and, if late evening, the 49 meter band (5,900–6,200 kHz). Jot down the frequencies where you hear stations and perhaps even make notes about the signal strength. Then go back home and see if you can receive as many stations. Shortwave stations change frequencies often, but if you listen from home at the same time the following evening, the radio landscape should be similar.

My guess is that you’ll hear many more stations in the field than you can from within your home.

Living with RFI

Sadly, RFI is just a fact of life in this century. It’s very hard to escape, especially for those of us living in dense urban areas. This is one of the reasons I’m such a big fan of taking radios to the field.

There are things you can do to improve reception and I would encourage you to read through this post from our archives (the first two points in the article directly address RFI). Do your best to track down sources of noise and eliminate them.

If you find that, even in the field, your shortwave receiver can’t receive stations with the antenna fully extended, then it may indeed be an issue with the radio itself and you might need to send it back to the manufacturer or retailer if it’s within the return window.

Post readers: If you have other suggestions, feel free to comment!


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Take the field and abandon the radio noise!

The most common complaint I hear from new SWLing Post readers is that they can’t hear stations from home on their receivers and transceivers. Nine times out of ten, it’s because their home environment is inundated with man-made electrical noises often referred to as QRM or RFI (radio frequency interference).

RFI can be debilitating. It doesn’t matter if you have a $20 portable radio or a $10,000 benchmark transceiver, noise will undermine both.

What can you do about it?

Since we like to play radio at home, we must find ways to mitigate it. A popular option is employing a good magnetic loop receive antenna (check out this article). Some readers find noise-cancelling DSP products (like those of bhi) helpful when paired with an appropriate antenna.

But the easiest way to deal with noise is to leave it behind.

Take your radio to a spot where man-made noises aren’t an issue.

Field radio

If you’ve been reading the SWLing Post for long, you’ll know how big of a fan I am of taking radios to the field–both transceivers and receivers. Not only do I love the great outdoors, but it’s the most effective way to leave RFI in the dust.

Sunday was a case in point (hence this post).

Let’s be clear: I blame Hazel…

Last week, I did a Parks on the Air (POTA) activation of Hampton Creek Cove State Natural Wildlife Area in Tennessee. It’s a beautiful area with a fantastic hiking trail (the Overmountain Victory Trail) in a relatively remote/rural area.

About 5 minutes before Hazel’s cow patty fun.

My family had a great time at the site–we enjoyed a picnic and I played radio–but Hazel (our trusty canine companion) decided to roll in a cow patty during our hike. Hazel thought it smelled wonderful. Her family? Much less so. And all five of us were staring at a two hour car ride together.

Fortunately, my wife had a bottle of bio-degradable soap we use while camping, so I washed Hazel in Hampton Creek. (Turns out, Hazel didn’t mind that nearly as much as getting washed at home in the tub.)

In all of the commotion I forgot to take my EFT Trail-Friendly antenna out of the tree. Doh!

The EFT Trail-Friendly antenna is incredibly compact and quite easy to deploy.

The EFT is my favorite field antenna for POTA activations. It works so well and is resonant on 40, 20 and 10 meters. With an ATU, I can also tune any bands in between. I’ve deployed this antenna at least 130 times in the field and it was still holding up.

I was bummed. Hampton Creek is nearly a four hour round-trip from my home. Was it worth the trip to rescue my antenna?

Fast-forward to Sunday: my amazing wife actually suggested we go back to Hampton Creek Cove on Sunday and also check out nearby Roan Mountain State Park. Would my antenna still be in the tree? Hopefully.

Whew! Still hanging out!

Fortunately, my antenna was still hanging there in the tree as I left it the week before. I was a little concerned the BNC end of the antenna may have gotten wet, but it was okay.

Mercy, mercy, so little noise…

I turned on my Elecraft KX2 and plugged in the antenna. Oddly, there was very little increase in the noise level after plugging in the antenna. That worried me–perhaps the antenna got wet after all? I visually inspected the antenna, then pressed the “tune” button on the KX2 and got a 1.4:1 SWR reading. Then I tuned around the 40 meter band and heard numerous loud stations.

What was so surprising was how quiet the band was that day (this time of year the 40M band is plagued with static crashes from thunderstorms).

Also, there were no man-made electrical noises to be heard.  This allowed my receiver to actually do its job. It was such a pleasure to operate Sunday–no listening fatigue at all. Later on, we set up at Roan Mountain State Park and did an activation there as well. Again, without any semblance of RFI.

When I’m in the field with conditions like this, I always tune around and listen to HF broadcast stations for a bit as well. It’s amazing how well weak signals pop out when the noise floor is so incredibly low.

It takes ten or so minutes to set up my POTA station in the field, but if you have a portable shortwave radio, it takes no time at all. None. Just extend the telescoping antenna and turn on the radio.

Or in the case of the Panny RF-2200 use its steerable ferrite bar antenna!

If you’re battling radio interference at home, I would encourage you to survey your local area and find a noise-free spot to play radio. It could be a park, or it could be a parking lot. It could even be a corner of your property. Simply take a portable radio outside and roam around until you find a peaceful spot with low-noise conditions. It’s the most cost-effective way to fight RFI!

Post readers: Do you have a favorite field radio spot? Do you have a favorite field radio? Please comment!

Also, check out these articles:

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John works with FCC to track down WX radar interference

Photo source: John (AE5X)

Many thanks to SWLing Post contributor, John Harper (AE5X), who notes that he recently worked with an FCC crew to find the source of noise that was affecting a weather radar site. In the process, John got to check out, first hand, RF Hawk and some of the equipment the FCC uses to locate interference (including pirate radio stations).

Click here to read John’s full post.

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