Category Archives: Field Radio

High Noon: Belka MW shootout part 2, with a review of the AFA200C active MW ferrite antenna

High Noon: Belka MW shootout part 2, with a review of the AFA200C active MW ferrite antenna

by 13dka

When I reviewed the updated Belka (gen3, 2022) for its MW/LW performance in October last year, I just wanted to know if it’s any good with just the whip antenna and used the XHDATA D-808 as a reference radio because it’s a Jay Allen 2.5-star average performer on MW and my expectations were not high for MW reception on a short whip.  To my surprise that average bar turned out way too low for the Belka!

That was sure asking for a comparison with the most sensitive MW radio I have and gave me hope to use the Belka for ultra-portable MW DXing on the move.  The omnidirectional whip doesn’t allow me to null out unwanted co-channel interference though, therefore I wanted to find a reasonably sized loopstick antenna to pair with the Belka.  Continue reading

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Short Video: Paul tunes in Rádio Nacional da Amazônia with his ATS25 in McGrath, Alaska

Many thanks to SWLing Post contributor, Paul Walker, who shares the following video of his open-air DX shack in McGrath, Alaska. Paul notes:

I got my iRig working and recorded audio of Rádio Nacional da Amazônia on 11780 kHz directly from the radio into my phone and it sounds really good with such a strong signal here in ALASKA. Take a listen….

Click here to view on YouTube.

Thanks for sharing this, Paul! That does sound amazing–like a local station!

You, sir, are a true DXer! Anyone who regularly braves frigid temps to chase far-flung DX is made of some incredibly tough stuff!

Thanks for sharing, Paul!

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Loop-On-Ground Antenna Part 3: Tom’s low-noise, low-profile, portable antenna evolves

Loop on Ground Antenna Part 3

(using multiconductor wire)

by TomL

It dawned on me recently, perhaps due to sloppy thinking or unintended distractions, that I never wrote about my modified Loop on Ground (LoG) receive antenna that I use at parks and such.  For over a year now, I have been using 3-conductor rotor wire bought cheap at the local hardware store and have wired the conductors in series.  Grayhat (Andrew) was the inspiration when he decided to create a folded dipole along the side of his house.

The usual construction of a LoG antenna for shortwave is a single wire of about 60 feet in circumference in order to not go above one wavelength for 20 meter band usage.  If you recall, going above one wavelength will start creating weird lobes in the reception pattern.  See – Loop-On-Ground Antenna Part 2.

However, I did not like this 19 foot diameter wire on the ground in public parks just waiting to be tripped over.  Like, the time when a horse got loose from its owners and almost tripped over my 60 foot wire.  I don’t think I would have liked the resulting lawsuit!

So out of fearful necessity I took some leftover RCA 3-conductor rotor wire, about 29 feet of it, and wired a loop with the conductors in series.  This gives about 81 feet of total conductive length.  But since it is folded onto itself, there is an undetermined loss of resonant length.  Callum (M0MCX) of DXCommander fame has experimented and found folded dipoles need three times more length in the folded section to reach resonance, so my loop is probably around 69 feet (electrically).  See – Fold the end of a Dipole Back – What’s Happening?.

In the picture below, the black wire with Ring Terminal at the bottom goes all the way around to the other side, soldered to the green wire, which goes around and is soldered to the red wire, which goes around to the Ring Terminal at the top, plus tie-wraps to hold the wires together.

The next picture is how the Wellbrook Medium Aperture preamplifier is connected to the loop with BNC cable that goes to the 12V power injector.  I have had this Wellbrook unit for maybe 6+years with no signs of problems.  WARNING – do NOT use the Wellbrook preamplifier in the presence of high powered RF energy like your Amateur Radio antenna pumped with 1000 watts from a  linear amplifier; the Wellbrook premap might just overload and get damaged!  I did use this loop and preamplifier at last year’s 2022 ARRL Field Day and was able to get away with it because we were only using 100 watts per station.  Listening to the 9pm 3916-net trivia group was fun but I still needed to keep it away from the transmitting antennas. Continue reading

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Radio Waves: Absolute Radio Turns Off AM in UK, Carlos Latuff Interview, X-Class Flaring, and Morse Code Is Back!

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


Absolute Radio to switch off all AM transmitters across the UK (Radio Today)

Bauer is removing Absolute Radio from Medium wave this month as it turns off all AM frequencies for the station across the country.

Absolute Radio launched exclusively on AM (as Virgin Radio) 30 years ago in 1993 using predominantly 1215 kHz along with fill-in relays on 1197, 1233, 1242 and 1260. Some of these have been turned off in recent years in places such as Devon, Merseyside and Tayside.

Whilst this is a historic milestone for the radio industry, it shouldn’t affect many listeners as just two percent of all radio listening currently takes place on AM.

Absolute Radio also lost its FM frequency in London in 2021 in favour of the ever-expanding Greatest Hits Radio network.

The move makes Absolute Radio a digital-only service, broadcasting nationally on DAB and online. [Continue reading…]

Coffee and Radio – with Carlos Latuff (Radio Heritage)

[…]Carlos Henrique Latuff de Sousa or simply “Carlos Latuff”, for friends, (born in Rio de Janeiro, November 30, 1968) is a famous Brazilian cartoonist and political activist. Latuff began his career as an illustrator in 1989 at a small advertising agency in downtown Rio de Janeiro. He became a cartoonist after publishing his first cartoon in a newsletter of the Stevadores Union in 1990, and continues to work for the trade union press to this day.

With the advent of the Internet, Latuff began his artistic activism, producing copyleft designs for the Zapatista movement. After a trip to the occupied territories of the West Bank in 1999, he became a sympathizer of the Palestinian cause in the context of the Israeli-Palestinian conflict and devoted much of his work to it. He became an anti-Zionist during this trip and today helps spread anti-Zionist ideals.

His page of Instagram (https://www.instagram.com/carloslatuff/) currently has more than 50 thousand followers, where of course you can see his work as a cartoonist and also shows his passion for radio. [Continue reading…]

X-CLASS SOLAR FLARE (Speaceweather.com)

A large and potentially dangerous sunspot is turning toward Earth. This morning (Jan. 6th at 0057 UT) it unleashed an X-class solar flare and caused a shortwave radio blackout over the South Pacific Ocean. Given the size and apparent complexity of the active region, there’s a good chance the explosions will continue in the days ahead. Full story @ Spaceweather.com ( https://spaceweather.com)

Looking to Ditch Twitter? Morse Code Is Back (Smithsonian Magazine)

For almost 20 years, Steve Galchutt, a retired graphic designer, has trekked up Colorado mountains accompanied by his pack of goats to contact strangers around the world using a language that is almost two centuries old, and that many people have given up for dead. On his climbs, Galchutt and his herd have scared away a bear grazing on raspberries, escaped from fast-moving forest fires, camped in subfreezing temperatures and teetered across a rickety cable bridge over a swift-moving river where one of his goats, Peanut, fell into the drink and then swam ashore and shook himself dry like a dog. “I know it sounds crazy, risking my life and my goats’ lives, but it gets in your blood,” he tells me by phone from his home in the town of Monument, Colorado. Sending Morse code from a mountaintop—altitude offers ham radios greater range—“is like being a clandestine spy and having your own secret language.”

Worldwide, Galchutt is one of fewer than three million amateur radio operators, called “hams,” who have government-issued licenses allowing them to transmit radio signals on specifically allocated frequencies. While most hams have moved on to more advanced communications modes, like digital messages, a hard-core group is sticking with Morse code, a telecommunications language that dates back to the early 1800s—and that offers a distinct pleasure and even relief to modern devotees.

Strangely enough, while the number of ham operators is declining globally, it’s growing in the United States, as is Morse code, by all accounts. ARRL (formerly the American Radio Relay League), based in Newington, Connecticut, the largest membership association of amateur radio enthusiasts in the world, reports that a recent worldwide ham radio contest—wherein hams garner points based on how many conversations they complete over the airwaves within a tight time frame—showed Morse code participants up 10 percent in 2021 over the year before.

This jump is remarkable, given that in the early 1990s, the Federal Communications Commission, which licenses all U.S. hams, dropped its requirement that beginner operators be proficient in Morse code; it’s also no longer regularly employed by military and maritime users, who had relied on Morse code as their main communications method since the very beginning of radio. Equipment sellers have noticed this trend, too. “The majority of our sales are [equipment for] Morse code,” says Scott Robbins, owner of ham radio equipment maker Vibroplex, founded in 1905, which touts itself as the oldest continuously operating business in amateur radio. “In 2021, we had the best year we’ve ever had … and I can’t see how the interest in Morse code tails off.”

Practitioners say they’re attracted by the simplicity of Morse code—it’s just dots and dashes, and it recalls a low-tech era when conversations moved more slowly. For hams like Thomas Witherspoon of North Carolina, using Morse code transmissions—sometimes abbreviated as CW, for “continuous wave”—offers a rare opportunity to accomplish tasks without high-tech help, like learning a foreign language instead of using a smartphone translator. “A lot of people now look only to tools. They want to purchase their way out of a situation.”

Morse code, on the other hand, requires you to use “the filter between your ears,” Witherspoon says. “I think a lot of people these days value that.” Indeed, some hams say that sending and receiving Morse code builds up neural connections that may not have existed before, much in the way that math or music exercises do. A 2017 study led by researchers from Ruhr University in Bochum, Germany, and from University Medical Center Utrecht in the Netherlands supports the notion that studying Morse code and languages alike boosts neuroplasticity in similar ways. [Continue reading…]


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Introducing the amazing SULA: An affordable unidirectional DX-grade loop antenna that you can build!

Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. The second article will focus on construction notes. The third and final article will essentially be a Q&A about the SULA antenna. All articles will eventually link to each other once published.

This wideband unidirectional antenna is an outstanding and innovative development for the portable DXer. I love the fact that it came to fruition via a collaboration between Grayhat and 13dka: two amazing gents and radio ambassadors on our SWLing.net discussion board and here on the SWLing Post. So many thanks to both of them!

Please enjoy and share SULA Part 1:


Introducing the Small Unidirectional Loop Antenna (SULA) 1-30MHz

A small and simple, unidirectional and DX-capable loop “beam” for SWLs!

by 13dka

In early June, Andrew (grayhat), SWLing Post‘s resident antenna wizard suggested a variation of the “cardioid loop” on the SWLing Post message board: The original “cardioid loop” is a small loop receiving antenna deriving its name from a cardioid shaped (unidirectional) radiation footprint. The design is strikingly simple but it has a few downsides: It relies on a custom preamp, it needs a ground rod to work and it is unidirectional only up to 8 MHz.

Andrew’s version had the components all shuffled around and it did not only lose the ground rod, it also promised a nice cardioid pattern over the entire shortwave, from a small, diamond shaped loop. Wait…what? It can be made using parts available on Amazon and your DIY store:

You need some 3m wire and PVC tubes to create a support structure to hold the wire, a 530 Ohm resistor and a 9:1 balun like the popular “NooElec One Nine”. Since it’s a “lossy” design, adding a generic LNA like the NooElec “LANA HF” would help getting most out of it. When you put that all together you have what sounds like an old shortwave listener’s dream: a small, portable, tangible, and completely practical allband shortwave reception beam antenna with some more convenient properties on top, for example, it is a bit afraid of heights.

That sounded both interesting and plain crazy, but the .nec files Andrew posted were clearly saying that this antenna is a thing now. Unfortunately Andrew suffered a little injury that kept him from making one of those right away, I on the other hand had almost all the needed parts in a drawer so I ended up making a prototype and putting it through some of its paces, with Andrew changing the design and me changing the actual antenna accordingly, then mounting it upside down. Let me show you around:

  •  Small, diamond shaped wire loop (with 76cm/29.92″ sides), needing as little space as most other small loops.
  • Unidirectional with a ~160° wide “beam” and one pronounced minimum with a front/back-ratio of typically 20dB over the entire reception range 1-30MHz.
  • Moderate height requirements: It works best up to 3m/10′ above ground, where it gives you…
  • …a main lobe with a convenient flat takeoff angle for DX
  • Antenna is comparatively insensitive to ground quality/conductivity.
  • Wideband design, works best on shortwave and is pretty good up to 70cm.

A functional small beam antenna for shortwave reception that’s just as small and possibly even more lightweight (prototype:~250g/9oz) than your regular SML, that can be easily made out of easy to obtain parts and easily carried around for mobile/portable DXing and due to its cardioid shaped directional pattern also for direction finding, a “tactical” antenna that’s also doing DX? Unlike conventional, Yagi-Uda or wire beams it can achieve a low takeoff angle at only 3m/10ft height or less, the front/back ratio is typically better than that of a 3-element Yagi, with a particularly useful horizontal pattern shape. That it’s rather indifferent to soil quality could mean that more people get to reproduce the good results and being a real wideband antenna is making the SULA an interesting companion for multiband radios and SDRs. Really? A miracle antenna? Is it that time of year again? If I had a dollar for every….

Continue reading

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A little off-line, off-grid camping

You might have noticed a lack of posts this weekend and that would be because I was completely off-grid and off-line, camping with two good friends in Pisgah National Forest.

It was brilliant, actually. I got to hang with friends I’ve known for over 30 years, test my new one person backpack tent (a.k.a. the “Bear Burrito”–the one on the right above), and of course I played a bit of radio.

Black bears are a fact of life here in the mountains of western North Carolina and we spotted three hanging out within 25 meters of our campsite.

By the way: the trick when camping with bears? Don’t put food in your tent, else that whole “bear burrito” thing becomes a reality.

I had a fabulous time putting my Elecraft KX1 “Ruby” on the air. I made perhaps 15 contacts in CW (Morse Code) with 3 watts of power.

One of the cool things about the KX1 is you can change the mode to SSB and actually tune through several shortwave broadcast bands (if you have the three or four band version of the KX1). Of course, I had to do a little SWLing.

As I mentioned in my previous post, I’m also a proper coffee snob and I firmly believe coffee tastes better when brewed outdoors. Yesterday morning, I brewed a pot of Rock Creek French Roast.

Off-grid, off-line camping recharges my internal batteries and it’s for this reason, I’ll be doing a lot more this year with my family.

It’s is also a brilliant way to experience an environment without any forms of radio interference (QRM or RFI). If you want to do some proper DXing, take your radio on some primitive camping experiences. It’ll remind you what life was like before switching power supplies ruled the world!

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How Giuseppe protects his Icom IC-705 during travels

Many thanks to SWLing Post contributor, Giuseppe Morlè (IZ0GZW), who writes:

Dear Thomas and Friends,

Giuseppe Morlè (IZ0GZW) here from Formia, central Italy.

This my latest video is about everything I have done to protect and transport my Icom IC-705.

I bought an aluminum case, light and very resistant with everything one needs inside to be able to use the IC-705.

    • 2 power banks, one of which is solar-charged to be able to recharge the battery while in operation
    • 2 wire antennas: a dipole type with BNC / banana socket with 10 meters of cable per arm and a 20 meter row, monopole, to be used in reception as you saw during the DXpedition to the Island of Ponza
    • I also bought the Mydel protective “cage” with antenna attachment on the front and PVC protection of the display

Given the high cost of this little jewel, it is advisable to take all precautions for its safety during transport and use.

Click here to view on YouTube.

I hope I made you happy …
Thank you all,
73. Giuseppe Morlè iz0gzw.

This is great, Giuseppe! Like you, I’ve taken extra measures to protect my Icom IC-705 as well. Your kit looks comprehensive–I love the fact that pretty much everything you need is inside. 

Thank you again. We always enjoy your posts from beautiful Italy. Ciao!

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