FTIOM & UBMP, April 4-10


From the Isle of Music, April 4-April 10:

This week, in honor of Jazz Appreciation Month, we reprise a 2020 episode with author Ricardo Oropesa and the music of Chano Pozo.
The broadcasts take place:
1. For Eastern Europe but audible well beyond the target area in most of the Eastern Hemisphere (including parts of East Asia and Oceania) with 100Kw, Sunday 1500-1600 UTC on SpaceLine, 9400 KHz, from Sofia, Bulgaria (1800-1900 MSK)
2. For the Americas and parts of Europe, Tuesday 0000-0100 on WBCQ (NEW UTC), 7490 kHz from Monticello, ME, USA (Monday 8-9PM EST in the US).
3 & 4. For Europe and sometimes beyond, Tuesday 1900-2000 UTC and Saturday 1200-1300 (NEW UTC) on Channel 292, 6070 kHz from Rohrbach, Germany.
Our Facebook page is https://www.facebook.com/fromtheisleofmusic/
Our V-Kontakte page is https://vk.com/fromtheisleofmusic
Our Patreon page is https://www.patreon.com/tilford

Uncle Bill’s Melting Pot, April 4-10:
In episode 211, we enjoy music from the Solomon Islands, Tonga and Vanuatu.
The transmissions take place:
1.Sunday 2200-2300 (NEW UTC) (6:00PM -7:00PM EST) on WBCQ The Planet 7490 kHz from the US to the Americas and parts of Europe
2. Tuesday 2000-2100 UTC on Channel 292, 6070 kHz from Rohrbach, Germany for Europe.
3. Saturday 0800-0900 UTC on Channel 292, 9670 kHz from Rohrbach, Germany for Europe with a directional booster aimed eastward.
Our Facebook page is https://www.facebook.com/UncleBillsMeltingPot/
Our V-Kontakte page is https://vk.com/fromtheisleofmusic
Our Patreon page is https://www.patreon.com/tilford

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Guest Post: Indoor Noise and Ferrites, Part1

Many thanks to SWLing Post contributor, TomL, who shares the following guest post:


Indoor Noise and Ferrites, Part 1

by TomL

My magnet wire loop antenna on the porch reminded me to revisit aspects about my noisy Condo that I still needed to understand.  Some RF noise I could control if I could find the right kind of information that is understandable to a non-engineer like me.  There is a lot written about the general problem of noise and radio listening, for instance this ARRL article with web links to research – www.arrl.org/radio-frequency-interference-rfi, but I needed to get more specific about my particular environment.

I had tried some common clamp-on TDK ferrites I had obtained from eBay a long time ago but they only seemed to work a little bit.  I have since found out these are probably the ones which are widely used on home stereo system connections used to reduce noise on those systems.  There must be a better way.

The more I researched topics, like a portable “Loop on Ground” antenna, or, using RF chokes on the magnet wire loop, it dawned on my feeble, misguided brain that I was wrongly thinking about how to use ferrite material.  For one thing, the material used to suppress RF noise is made with a certain “mix” of elements, like Manganese-Zinc, that electrically “resists” a specified frequency range.  Fair-Rite has a useful Material Data Sheets web page which lists the Types of ferrite material.  For dealing with noise (at the Source causing the problem), I needed to use the right kind of “Suppression” materials and proper placement.  So, it (partly) made sense why the TDK snap-on ferrites might not fully work to reduce certain noise coming from my computer screens, LED lights, USB devices, and cheap Chinese-made power adapters.

A very good  paper is by Jim Brown (K9YC) of Audio Systems Group entitled, “Understanding How Ferrites Can Prevent and Eliminate RF Interference to Audio Systems [PDF]”.  There is a longer paper speaking directly to Amateur Radio folks, but the Audio version is simpler and it uses some of the same  graphs and ideas.  I was drawn to the very detailed Impedance measurements of many different “Types” of ferrite material used for different noise mitigation.  I remember the traumatic pain of my college experience trying mightily to understand the Van Vlack Materials Science text book to no avail.  But Jim’s paper reminded me of the importance of using the correct type of ferrite material and in an optimal way that reacts favorably in the target frequency range to solve a particular noise problem.  So, what are my problem areas?

Shortwave Noise

Loop antennas have been what I have experimented with the most.  They do not pick up as much man-made noise (QRM) and they have a space saving footprint.  Fortunately, there is a wooden porch where these things have been tried.  I had successfully built a broadband amplified “ferrite sleeve loop” (FSL) in the past.  It was useful for a while but it fell into disrepair and also the Condo building has steadily increased in noise output.  The amplifier was just amplifying the noise after a while.  I also tried phasing two antennas but found the ever increasing noise cloud was coming from all directions and I could not null it out.  I even tried a “mini-whip” from eBay but that just produced a wall of noise.

I recently tested AirSpy’s YouLoop written about before, and the results were good.  However, it seemed obvious to me that it was too small as a passive loop to capture shortwave signals strongly enough without resorting to another amplifier attached at the antenna and would not improve the signal/noise ratio.  My current solution is a unamplified stealth magnet wire loop about 32 feet in circumference.  In that article, I mention things like common mode RF chokes at both ends of the antenna connection, horizontal polarization, and basically accepting that only the stronger shortwave signals will be received in a predictable manner.  I think for now, this is about all I can do for shortwave and mediumwave noise, as far as my own Condo-generated noise. Neighborhood noise is a different topic.

VHF Noise

I then started to isolate which devices caused which kind of noise when listening to my outside amplified antennas for FM/VHF and UHF-TV transmissions.  Many consumer Power adapters make a lot of noise from VLF up into UHF ranges.  One thing I did right was to try a 10 pack of these little miracle “Wall Wart” toroids from Palomar Engineers.  One by one, I put one of these small toroids (19mm inside diameter) on my home AC adapters as shown in the pictures, and the noises started disappearing.  It does not explicitly say, but I believe it is Type 75 material which suppresses the noise generating AC adapter (at very low frequencies) when wrapped 8 – 12 times.

Most egregious of these was my CCrane FM2 transmitter.  A strangled warbling sound kept emanating from the monitor closest to my laptop. Installing ferrites on the laptop and back of the monitor were not working.  I moved the FM Transmitter and noticed a reduction in noise.  So, I put one of these little toroids on the power input of the device and the noise disappeared.  Apparently, it was picking up noise from the monitor (as well as its own power adapter) and rebroadcasting it to all my other radios!  The strangled warbler is no more, I choked it (HaHa, sick bird joke).

While looking for the monitor noise, I put the eBay TDK ferrites on all the USB ports and HDMI ports.  This has helped greatly on VHF and confirms my suspicion that these cheap TDK ferrites are indeed a common type of ferrite material.  Some informative graphs can be seen in Jim Brown’s Audio paper mentioned before.  One example might be Figure 22, which shows the #61 Series Resistance which peaks around 100 MHz when using a toroid with three “Turns”.  More confused, I could not find a definition of a “Turn”.  Eventually, in his longer paper to Amateur Radio operators, he defines it, “…is one more than the number of turns external to the cores”.  Somewhere else he describes using many single snap-on ferrites being electrically equal to just one toroidal ferrite with multiple Turns.  And interestingly, more Turns shifts the peak impedance substantially lower in frequency.  So, using the graphs he supplies, one can target a noisy frequency range to try to suppress.

I then put 6 of the TDK ferrites on the VHF input to the AirSpy HF+.  Some FM grunge was reduced and was thankful for that.  The rest of the background noise truly seems to be coming from the outside picked up by the amplified antenna.

Also, I juggled a couple of the amplifiers around and now have separate VHF/FM and UHF/TV amplifiers which cleaned up the FM reception a little bit more – https://www.youtube.com/watch?v=zkDsy95et2w .

UHF TV Quality

On a whim, I put the balance of the TDK ferrites on the FM/TV splitter input cable, 10 in all.  The FM reception did not improve but the Over The Air UHF TV reception Quality improved noticeably.  My weakest TV station now has a stable Signal level and the Quality is pegged at 100%.  This is a nice surprise since it means that now all local TV stations on UHF will come in cleanly without dropouts and I can view all digital subchannels.  I was even able to rescan and added two more low-power stations never seen before. ?

LED lights

I have common LED lights hanging over a number of fish tanks and some grow lights over an indoor plant box and can hear this noise on upper shortwave and higher radio bands.  In a future article, I will explore RF noise from lights as its own special topic. For instance, why do some LED lights generate RFI and how to know before buying (I am using BR30 spot bulbs from name brands)?  Also, there is a new kind of LED “filament” light out now that uses much smaller LED’s on both sides of an aluminum strip, greatly reducing electromagnetic noise output (or do they??).  More questions than answers.

I will explore creating my own customized AC power cord attached to the AC power strips of the LED lights.  I will need to test this for safety and efficacy, so I will want to take some time to do this right.  The hope is that, using Jim’s info, I will be able to create a broad spectrum RFI suppression AC power cord and cost less than $30 each cord.  We’ll see.

Finally, I will look at “stacked” toroids using different mixes of ferrite Types, creating a custom RF suppression better than using just one Type of ferrite material, using AC cords as the main examples. For instance, the best set of graphs in Jim’s paper, in my opinion, are Figures 21 and 24 compared to each other.  Something I did not know before is that one can not only use multiple turns on a single toroid to get a lower, peaked frequency response, but also stack multiple toroids of the same Type to get a smoother frequency response.  Then on top of this, combine that set with other Types to create a customized frequency response curve.

Radios are quieter now.  Those pesky grow lights are still a problem as well as the upstairs neighbor’s lights which seem to be on a timer, making FM reception noisy again after 5pm!

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A new Belka-DX DSP Speaker from Mobimax

Many thanks to SWLing Post contributor, Markku (VA3MK), who shares a link to this new Belka-DX speaker option from Mobimax:

This speaker option is similar to the one we featured a few months ago, but keeps the larger 2200 mAh battery pack and has fold-out legs. The compromise is the case will be a bit thicker/deeper than the speaker option without the larger battery and fold-out feet.

We’re talking about a pretty small radio, though, so I think this will be another great option for the excellent little Belka-DX.

I will plan to check out one of these in the near future.

Thank you for the tip, Markku!

Click here to check out this product at Mobimax.

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How to give your Reciva WiFi radio a second life before the service closes on April 30, 2021

The C.Crane CC Wifi

In November 2020, we learned that the Reciva radio station aggregator would be closing down permanently which would effectively render a large portion of WiFi radios on the market useless. This closure will affect a number of WiFi radio manufacturers, but two of the most notable are Grace Digital and C.Crane. I own one of each.

The Grace Digital Mondo

The comments section of my original post about the Reciva closure became the default discussion group for Reciva device owners who were trying to sort out options to keep their devices functional. That article (at time of posting) has nearly 200 comments alone.

There have been some very productive discussions about circumventing the Reciva aggregator before the announced closure on April 30, 2021. Since this information is buried in such a deep comment thread, I wanted to give it better visibility and search-ability by creating a dedicated post on this topic.

Ray Robinson, one of the contributors who has been actively helping owners, has very kindly written up a tutorial for us here and I’m most grateful.

Ray’s Guide to setting up your own “Reciva” WiFi webserver

Ray writes:

[T]he bad news is that Qualcom is shutting down the Reciva website on April 30th, and any Reciva-based Internet radios will no longer be able to tune stations from that aggregator after the shutdown.

The sort-of good news is that if you have a station link stored in a preset on your Internet radio, the preset should continue to work after April 30th, until such time in the future as the station needs to change the link for their webstream.

Because, the other part of the bad news is that most Internet radios don’t have any way of directly inputting or modifying a webstream, or storing a webstream manually in a preset. So, after April 30th, you would lose any ability to change or update any of the presets.

That’s where my work-around comes in. Internet radios do have the in-built ability to address and pull data from a webserver – that’s how they use the Reciva site in the first place. So what I have done is point my radio (a CCWiFi) to a ‘web server’ on my local network instead. This solution uses a Windows PC; there may be a comparable solution using a Mac or a Linux box, but I’m not familiar with either of those.

First, make sure the PC you are going to use is visible to other PC’s and devices on your local network (‘Network Discovery’ turned on, file sharing enabled, etc.).
Second, I recommend you give the PC a reserved internal IP address in your router. If you leave it with IP being assigned by DHCP, its IP address could change anytime it is rebooted, and then your wi-fi radio won’t be able to find it for the presets. In my router, I assigned 192.168.1.1-200 for DHCP, and then gave my PC the reserved address of 192.168.1.201, which ensures it always has that same address.

Third, enable IIS (Microsoft’s ‘Internet Information Services’) in Windows. This will create a local web server on the machine. In Control, Panel, go to Programs / Turn Windows features on or off. Click the box next to Internet Information Services and OK, and let Windows install that component.

We are going to store our station webstream links on the PC in playlist files, which have the file extension of .pls. But first we have to tell IIS what to do with a .pls file, as it doesn’t know by default. (.m3u files will work as well, but I did it with .pls files, so I’ll detail how to use those.) We do this by adding a MIME type. Click the Windows start button, and search for IIS. The top result will be Internet Information Services (IIS) Manager. Click that. In the center of the panel that opens, click MIME Types and then ‘Open Feature’ at the top on the right. This will show you all the extensions IIS knows about. If you scroll down, you will see there isn’t one for .pls. So, we need to create it. At top right, click Add… In the panel that opens, enter a File name extension of .pls and a MIME type of application/pls+xml Then click OK and exit IIS.

If you now look in the root of the C: drive, you will see there is a folder called inetpub, with a subfolder called wwwroot. This is where we want to store the presets.

My CCWiFi has 99 presets, so I have put 99 files in this subfolder, named from Preset01.pls to Preset99.pls.

As an example, my first preset, Preset01.pls, is for Caroline Flashback. To create the .pls, open Notepad, and copy and paste the following:


[playlist]
NumberOfEntries=1
File1=http://sc2.radiocaroline.net:10558
Title1=Caroline Flashback
Length1=-1

Save the file, but change its extension from .txt to .pls.

Then, in Reciva, I need to store the entry in My Streams that will tell the CCWiFi to come and look at that file to know what to play. On the Reciva site in My Streams, I created a stream titled ’01 Caroline Flashback’ with a stream address of ‘http://192.168.1.201:80/Preset01.pls’ Remember, my PC has a reserved address of 201. If you use something different, then you will need to change the stream address accordingly.

Then, on the CCWiFi, go to My Stuff / MyStreams and select ’01 Caroline Flashback’. Reciva is telling the CCWiFi to go to my PC and look at the contents of Preset01.pls. This it does, and starts playing the stream. Then, it’s just a matter of storing that playing stream in preset 1 on the radio.

With that done, at any time in the future if I decide to change the contents of that .pls file, I can just store the details of any other station/stream, and the radio will play that instead without any reference back to Reciva.

I recommend you do that for all available presets on your Internet radio whether you are using them or not, even if they only contain duplicate entries for now, because that way you will maintain access to be able to use those presets in the future. And, you must do this before April 30th, when the Reciva site will shut down.

Actually obtaining the URL of a station’s webstream can be difficult; some stations are very helpful and provide them all on their website, while others seem to do their best to hide them. However, here in Los Angeles, I have found the webstream URL’s of all of our local AM and FM stations, plus the webstream URL’s of all North American SW stations, and all the UK stations as well (both BBC and commercial). I’d be happy to advise on that also, but it’s probably beyond the scope of this particular tutorial!

Thank you so much Ray, for taking the time to write up this tutorial.

If anyone is familiar with how to set up a similar webserver on MacOS or Linux, feel free to comment with details.

By the way Post readers: if the name Ray Robinson sounds familiar, it’s because he’s a weekly contributor to AWR Wavescan, and also a presenter on Radio Caroline Flashback!

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Dan spots a rare Collins 51S1 LTV G133 F military receiver on eBay

Many thanks to SWLing Post contributor, Dan Robinson, who notes:

This military version of the 51S-1 receiver is almost never seen on the used market.

Click here to view on eBay.

Thank you, Dan! The seller claims that this radio is fully working with tubes replaced and has undergone a complete alignment. Hopefully, caps have been replaced as well.

I’ll admit: if I had the space, I would add this rig to my collection in a heartbeat, although I expect the price of this unit will far exceed my budget!  It is a beauty, though.

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HF-START Web Tool: A new web-based, real-time shortwave radio propagation application

Many thanks to SWLing Post contributor, Tracy Wood, who shares the following journal abstract from EurekaAlert.com:

Commencement of shortwave propagation simulator (HF-START) service

Demonstrating radio wave propagation paths between any two points based on real-time space weather information

NATIONAL INSTITUTE OF INFORMATION AND COMMUNICATIONS TECHNOLOGY (NICT)

[Abstract]

The National Institute of Information and Communications Technology (NICT, President: TOKUDA Hideyuki, Ph.D.), in collaboration with Electronic Navigation Research Institute, National Institute of Maritime, Port and Aviation Technology (ENRI, Director General: FUKUDA Yutaka) and Chiba University (President: TOKUHISA Takeshi), has started the service of shortwave propagation simulator (HF-START). It provides real-time shortwave propagation that reflects real space weather information from ground-based observations and model calculations. The HF-START web system has been successfully developed and is now available at https://hfstart.nict.go.jp/.

The web calculation function of this system allows shortwave propagation between any two points in Japan based on real-time GNSS observations and between any two points on the Earth based on model-based space weather information. Real-time estimation is possible. The calculation in the past and up to about 1 day ahead in the future is also possible. In addition to amateur radio, HF-START is expected to benefit efficient frequency operation of aviation communications that relies on shortwave in the polar route.

[Background]

Communication and positioning technologies play an important role in social infrastructure in various fields today. The ionosphere has regular temporal cycles and fluctuates greatly every day associated with solar activity and space environment. Of benefit to us is the fact that ionosphere is good at refracting shortwave, which is why we can hop shortwave signals off the ionosphere to communicate with people over large distances.

Shortwave band has been used for communication and broadcasting for a long time, and are still widely used in radio broadcasting, aviation communication, amateur radio, etc. Ionospheric variation, however, has a great influence on the propagation of radio waves. Communication environment such as the communication range and usable frequency changes significantly due to the influence of the ionospheric fluctuation. Thus, fluctuations in the ionosphere affect the operation of shortwave broadcasting, aviation communications, and amateur radio.

There have been websites that provide estimated information on how radio wave propagation changes due to such ionospheric fluctuations. The problem is that it is based on a simple model and does not reflect realistic ionospheric fluctuations.

[Achievements]

We have developed a shortwave propagation simulator HF-START that estimates and provides shortwave propagation information in real-time under realistic ionospheric fluctuations based on ground-based observations and model calculations. We open real-time information estimated by HF-START, and the web application at https://hfstart.nict.go.jp/.

Figure 1 shows an example of visualization of shortwave propagation by HF-START. In this system, the user can check the radio wave propagation information that is updated in real-time. As shown in Figure 2, the user can also use the web application to estimate and visualize radio wave propagation by specifying any frequency in the range of 3-30 MHz, any two points on the Earth, and any transmission angle. The date and time can be set retroactively to the past (after 2016), to the real-time, and in the future (up to about 1 day ahead).

The system can be used to visualize the radio propagation path and clarify whether it is affected by space weather when the shortwave you are using does not reach the destination, or when you can listen shortwave broadcasted from the far source that normally you cannot hear. Furthermore, in addition to amateur radio, it is expected to benefit efficient frequency operation of the aircrafts that use shortwave in polar route.

[Future Prospects]

We are conducting research and development to extend the HF-START to estimate radio wave propagation not only in the shortwave band but also in other frequency bands. In addition, we will evaluate the simulator accuracy and improve it by comparing it with radio wave propagation observations.

NICT has been providing information related to communications, satellite positioning, and radiation exposure since November 2019 as a member of the Global Space Weather Center of the International Civil Aviation Organization (ICAO). With the HF-START service, we expect to improve the information provided to directly relate to communications, such as communication range information.

###

As the abstract mentions, you can use the tool online now via the HF-Start Web Tool.

Thanks so much for the tip, Tracy. This is fascinating!

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Jack finds that chokes have a huge impact on switching power supply noise

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

Many thanks to SWLing Post contributor, Jack Dully, who writes:

I was putting some things in my radio junk parts box and came across some chokes. So I tried a test with my Tecsun PL-880 on battery and the Tecsun supplied switching AC adapter, with and without chokes on the adapter.

WOW!

I tuned to a vacant station on battery power with headphones on. Then on AC power, the hash and static were incredible. Putting one large choke on the adapter power cord, wrapped about four times and it decreased considerably. So I attached a second choke and once again the static & hash decreased even more, almost to the point of sounding like I was running just on battery power.

Those chokes really do work well.

Thank you for sharing this, Jack. I almost never operate my portables while connected to a power supply, so I often forget about the importance of using a choke with inexpensive, lightweight radio power supplies. Thing is, so many things in our houses and shacks are powered by these QRM generators. In the shack, I’ve added chokes I’ve picked up at hamfests to a number of various power supplies. It does certainly help decrease the noise level. I’ve even used them on power cords for other appliances in the house that tend to spew RFI.

If you ever find a deal on chokes at a hamfest or electronics store, grab some. They can be an affordable solution for those noisy power supplies we still rely on.

Thank you for the reminder and  tip, Jack!

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