Category Archives: Articles

From SolderSmoke: Watching Shortwave Broadcast Stations on the TinySA Spectrum Analyser

Curtain Antennas at VOA Site B: Greenville, North Carolina.

Many thanks to SWLing Post contributor and friend, Bill Meara, from the amazing SolderSmoke podcast who shares the following post that originally appeared on the SolderSmoke Daily News:


Watching Shortwave Broadcast Stations on the TinySA Spectrum Analyser

by Bill Meara

November 18, 2022 1244 UTC. I was using a TinySA spectrum analyzer to look at noise levels on the 40 meter ham radio band. I also wanted to take a look slightly above the band (in frequency) to see Radio Marti at 7355 kHz. As I was doing this I remembered that Vatican Radio was on the air at 7305 kHz from 1230 UTC to 1245 UTC. So was just going to catch the last moments of that day’s transmissions. Sure enough, I caught it, and watched it disappear from the TinySA screen. See the video below:

Click her to view on YouTube.

Radio Marti continued on. In the morning we can hear the rooster recordings from that station. We are using it to test how well our homebrew Direct Conversion receivers avoid AM detection. In the video I mistakenly said these two transmitters were on the air with 250 megawatts. The correct power is 250 kilowatts. Both transmit from Greenville NC. I think the signal from Vatican Radio is stronger here because they are using a different antenna pattern — Radio Marti is aimed at Cuba.

This reminds me of a cool project I have not yet done: modifying the TinySA to allow the user to listen to the station: https://soldersmoke.blogspot.com/2021/10/how-to-listen-with-your-tinysa.html I notice that Dean KK4DAS (my colleague in DC receiver design) was the only commenter on the blog post describing the TinySA mod. TRGHS. We need to to do this.

Here are the reports showing when Vatican Radio and Radio Marti were on the air on November 18, 2022:


Thank you for sharing this, Bill. I love it! The TinySA is such an affordable and useful workbench tool.

Post readers: If you love building things and exploring a wide range of radio projects, I highly recommend bookmarking the SolderSmoke Podcast and website

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13dka Reviews: The new 2022 “Belka” (generation 3) general coverage receiver

The new 2022 “Belka” (generation 3) general coverage receiver

by 13dka

Since its introduction in 2019, the super-tiny Belka (back then called “Belka DSP”) shortwave receiver sure gained an enthusiastic followership among SWLs and hams. The main reason for this is certainly the way how the Belka is incredibly small yet playing in a different league than the various consumer grade, Chinese mass-production radios, particularly the DSP-based ultraportables: The Belka is an all-mode shortwave communications receiver with a completely different (direct conversion SDR) architecture, developed and produced by a radio enthusiast (Alex, EU1ME) in a small mom&pop shop in Belarus.

In case you’ve never heard about it amidst all the buzz about more popular brands, here’s the skinny:

The Belka offers true allmode (including NFM and CW) reception with a proper 400 Hz CW filter and individual settings for the low and high filter slopes for AM, FM and SSB. It has an AM sync detector and comes with a 0.5ppm TCXO-controlled local oscillator for absolutely spot-on, calibration-free frequency precision and stability, which makes SSB or ECSS reception of broadcast stations a pure joy. The second iteration “Belka DX” brought a slightly extended coverage down to 1.5 MHz and an I/Q output for panadapter display and/or processing via your favorite SDR software.

All Belkas are quiet and very sensitive radios with a surprisingly robust front end, the filters are better and its AGC works like you’d expect it from a communications receiver, without the artifacts and distortion the DSP radios are infamous for, and of course smooth, non-“muting” tuning in variable steps down to 10Hz.

The Belkas have no built-in speaker (available as option tho) but really excellent audio on headphones and external speakers and they actually give my Icom IC-705 a run for its money in terms of reception quality, and they do that for up to 24 hours on a single charge of the internal Li-Ion battery. This stunning feature set is crowned by the best performance on a telescopic whip antenna ever – the Belkas have a high-impedance (>10 kOhm) antenna input optimized for this whip and taking it on a walk is (really!) like having a big rig with a big antenna in tow…

Despite all this goodness setting the Belka(s) quite fundamentally apart from most (if not all) current and former, even much higher priced portables and simultaneously putting it solidly into pricey tabletop territory, it hasn’t put Tecsun et al out of business for a couple of reasons: One reason is that it can only be obtained from Alex in Belarus, which is now often assumed to be impossible (it isn’t, more on that later). Another reason is that it doesn’t try to compete with aforementioned multiband radios from China, so there is no FM broadcast band and – until now – no AM BC band, but most owners and potential buyers particularly in the US really wished it had at least the latter. Well, Alex obviously heard us! After the Belka DSP and the Belka DX, the new Belka is just called “Belka”, so in order to avoid any ambiguity I’m going to refer to this model as “Belka 2022”.

What’s new?

The most prominent addition to the Belka 2022 is the extended 0.1-31 MHz coverage, the previous version only started receiving at 1.5 MHz. With LW and MW included, its “pseudosynchronous” detector (as featured in venerable radios from Harris, Racal or Drake), the great filtering and the great frequency precision for hassle-free ECSS reception are promising that the “squirrel” is now an ultra-ultraportable companion for MW DXers as well.

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Mario shares a short review of the Airspy HF+ Discovery SDR

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), who shares the following guest post:


Author’s Airspy HF+ Discovery (small black box to the left of the laptop)

A Short Review of the Airspy HF+ Discovery SDR

by Mario Filippi (N2HUN)

I recently purchased an AirSpy HF+ Discovery.  As a SWL for over 60 years who’s owned many shortwave radios by manufacturers such as Drake, Yaesu, Icom, Zenith, Kenwood, Panasonic, Sony, Radio Shack, Grundig, CountyComm, MFJ, Sears, AOR and have used a number of different SDRs such as the RTL-SDR.com, HackRF, NooElec and many other rudimentary inexpensive first generation SDR dongles, I feel the AirSpy was an excellent choice. It cost $169 plus shipping.

For LW/MW/HF reception, I use a 30’ ground mounted vertical with about 50 buried radials in different stages of decomposition hihi. For VHF, a roof mounted 2m/70cm SlimJim antenna is used, but I haven’t done much listening in that portion of the spectrum yet except for occasional foray into the aero, 2m ham, NOAA satellite and public service bands.  Note that the AirSpy also covers 60 – 260MHz.

An older Dell Inspiron laptop and SDR# are used in conjunction with the AirSpy.  For decoding, MultiPSK, FLDigi, MTTY, Yand (for NAVTEX), along with VB cable are the accompanying software to make the digital modes intelligible.

So far I’ve logged a few local LF aeronautical beacons and some DGPS beacons on longwave but will be in a better position to judge its performance when winter sets in.  As for the medium (520 – 1710 kHz) wave AM broadcast band, the AirSpy easily brings in both local stations during daytime and distant stations at night with no adjacent channel interference whatsoever.  Even low powered community Emergency Alert Stations in the 1600 – 1710 kHz portion of the band can be heard daily from this QTH. A rotatable loop would certainly improve reception though.

As for shortwave listening the AirSpy HF+Discovery is, in my opinion, great for listening to both shortwave broadcasts and utility stations though I tend to concentrate on UTES mostly such as VOLMET, WEFAX, RTTY (the few that remain unencrypted), CW marker stations (e.g. XSG and XSQ from China) NAVTEX (519 kHz), aero/maritime SSB, time signal stations (WWV, CHU) and many of the other esoteric digital utility signals populating the band.  As for SW broadcast stations, WRMI, Radio Exterior, RFI, R. Marti,  BBC, WWCR and Radio Algerienne, to mention a few have been received.  The Frequency Manager (memory storage) in SDR# has quickly filled up with intercepts using the AirSpy.

As a ham and CB operator (yes, the two can mutually coexist in the same human body), I’ve found the AirSpy HF+ Discovery to be a trouper on all the HF ham and CB bands. One of my favorite hangouts is the 28.100 – 28.300 MHz slice of 10m where domestic and international low power CW beacons transmit their callsigns (and at times their grid squares and power output) into the ionosphere and achieve great distances.  Recently, beacons from 5, 6 and 7 land in the US along with DX prefixes ED4, PY4 and XE1 were logged.  If you’re into 10m FM operation you can also tune the AirSpy to hear local and distant repeaters on 29.62 – 29.68 MHz.  When the band is open, .62 and .64 seem to be the most active here in Central NJ.

If you’re a CB (aptly named the Citizen’s Band) op, the AirSpy HF+ Discovery does a stellar job on Channels 1 – 40 which is especially exciting when the band’s open.  While domestic (USA)  CB’ers are limited to frequencies from 26.965 – 27.405 MHz you’ll nonetheless hear DX ops below our (USA) channel 1 and above channel 40 conversing in French, Spanish and German in LSB/USB.  Add to this mix the fact that the FCC dropped the 150 mile limit for US ops a few years back and now the advent of the FM mode operation in the US, you’ll find the AirSpy won’t disappoint.  In my opinion the AirSpy HF+Discovery was an excellent choice and I’m more than satisfied with its performance.

In the matter of honesty and full disclosure, I purchased the AirSpy HF+ Discovery completely on my own in an effort to upgrade my station.  My choice was based on information gathered from the Internet and YouTube video reviews.  The performance of this receiver was based on my experience using the vertical antenna described earlier, the hours spent at my QTH (location) listening to stations of interest to me and my six decades experience as a SWL.  No test equipment to assess sensitivity, selectivity or other empirical methods to measure performance was used. That information can be found on the Airspy website.  The main purpose of this article was to craft a rudimentary review for those interested with the caveat that reception will vary depending on many factors such as location, antenna, ionospheric conditions, feedline quality, computer/software variations, QRN, QRM, and operator experience.  The results presented in this article are typical for my location; others may experience different results.  Thanks very much.

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Radio Waves: Maverick-603 SDR for FT8, EC-130J Commando Solo Final Broadcast, WRTH Survey, and Railways On The Air

EC-130J Photo By Staff Sgt. Tony Harp | An EC-130J Commando Solo aircraft from the 193rd Special Operations Wing performs a flyover during Community Days at the Lancaster Airport in Lititz, Pennsylvania, Sept.17, 2022. (Source: DVIDS)

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!


RadioStack’s Maverick-603 Is a Fully-Functional Open-Silicon Software-Defined Radio for FT8 (Hackster.io)

Built using open tools and readied for manufacturing at SkyWater using the Efabless platform, the chip on this SDR is something special.

New Hampshire-based RadioStack is looking to launch a piece of amateur radio equipment with a difference: the Maverick-603 is powered by free and open source silicon, built using the Efabless platform at a SkyWater fab.

“Maverick-603 is the first affordable FT8 receiver board built around an RF receiver chip that was designed using fully open source tools and fabrication,” its creators explain. “It is capable of acquiring FT8 signals between 7MHz and 70MHz. With this frequency range, you will be able to receive signals from around the world with high accuracy. The use of our Low Noise Amplifier (LNA) will also give the chip the ability to amplify very low-strength signals, which is necessary for an effective FT8 receiver.” [Continue reading…]

EC-130J Commando Solo performs final broadcast (DVIDS)

MIDDLETOWN, PA, UNITED STATES
09.17.2022
Story by Master Sgt. Alexander Farver
193rd Special Operations Wing

Airmen from the 193rd Special Operations Wing here, who operate the only flying military radio and TV broadcast platform in the U.S. military, transmitted their final broadcast today to spectators at the Community Days Air Show at Lancaster Airport, Lititz, Pa., bringing to close a 54-year chapter in unit history.

The EC-130J Commando Solo mission has helped keep this Air National Guard unit’s aircraft and its Airmen at the tip of spear for nearly every major U.S. military operation since the Vietnam War. Before bombs dropped or troops deployed in the Global War on Terror following the attacks on Sept. 11, 2001, this specially modified aircraft was already over the skies of Afghanistan broadcasting to America’s enemies that the U.S. military was bringing the fight to them.

“Any world event or crisis that our military has responded to in recent history, our 193rd Airmen – and Commando Solo – were likely key components in that response,” said Col. Eric McKissick, 193rd SOW vice commander. “As we prepare to open a new chapter in our history, we thank those who have enabled us to be among the very best wings in the Air National Guard.”
The genesis for this airborne information operations platform can be traced back to 1968 when the 193rd Tactical Electronics Warfare Group received its first aircraft, called the EC-121 Coronet Solo. In the late 1970s, the aircraft were replaced by the EC-130E before finally being replaced by the current aircraft in 2003. Throughout its history, it was instrumental in the success of coordinated military information support operations, earning the wing the moniker of “the most deployed unit in the Air National Guard.”

These deployments included: Operation Enduring Freedom, Operation Iraqi Freedom, Operations Odyssey Dawn/Unified Protector in Libya, Operation Inherent Resolve, Operation Resolute Support/Freedom’s Sentinel, Operation Secure Tomorrow and Operation Unified Response in Haiti.

Although this unique mission has earned the wing many prestigious accolades, Lt. Col. Michael Hackman, 193rd Special Operations Squadron commander, believes the mission’s success and legacy lies in winning the hearts and minds of adversaries and providing vital information to allies, refugees and victims in times of crisis.

“This capability has been an essential tool in our nation’s inventory, from the battlefields to assisting hurricane and earthquake-ravaged nations,” Hackman said. “During this time, thousands of Pennsylvania Air National Guard volunteers fulfilled their call to duty in this unique capacity, leveraging this capability against U.S. adversaries and supporting allies while always fulfilling the unit tenet of ‘Never Seen, Always Heard.’”

Aside from sporting an impressive operational record, the aircraft holds another distinction with having completed over 226,000 hours of accident-free flying.

“Having that many thousands of hours of accident-free flying is a testament to the excellence of our maintainers, to the operators and anybody who has touched that aircraft. Thank you for leaving that foundation and setting that example that we’re building from,” said Col. Jaime Ramirez, 193rd Special Operations Maintenance Group commander.

McKissick believes the success of the 193rd in operating the Commando Solo mission over the past few decades has led to Air Force Special Operations Command selecting the wing to be the first and only ANG unit to operate the MC-130J Commando II. The Commando II flies clandestine, or low visibility, single or multiship, low-level infiltration, exfiltration and resupply of special operations forces, by airdrop or airland and air refueling missions for special operations helicopters and tiltrotor aircraft, intruding politically sensitive or hostile territories.
“Today we honor the men and women, past and present, who have served this unit and mission with unparalleled distinction,” said McKissick. “The Airmen who came before us created an enduring culture and spirit of hard work, innovation and grit. We thank them for that, and we will do our best to carry this forward.”

The final broadcast of the EC-130J was transmitted to the ground and played at the Community Days Air Show at Lancaster Airport. In the transmission, the wing thanked the local community for their support over the past 54 years before broadcasting the Santo and Johnny song, “Sleepwalk.” The transmission ended with the phrase, “Commando Solo, music off.” [Read the full article here…]

WRTH Reader Survey

The new owners of the World Radio TV Handbook who like your input as readers. Please click on this link and share your opinions with them!

Railways On The Air (Southgate ARC)

The South Eastern Amateur Radio Group (EI2WRC) will be active from The Waterford and Suir Valley Railway station Kilmeaden, Co. Waterford for the ‘Railways On The Air‘ event on Sunday, the 25th of September.

WSVR is a community heritage project. The project has enabled the magic of rails golden age to be brought to life in Kilmeaden. A heritage narrow gauge railway runs along 17 kilometres of the abandoned Waterford to Dungarvan line.

The South Eastern Amateur Radio Group would like to thank the manager Maria Kyte and all the staff of The Waterford and Suir Valley Railway for all their help and allowing us access to the station to do this event again this year. For more information about the WSVR please see www.wsvrailway.ie .

The September meeting of the South Eastern Amateur Radio Group EI2WRC will take place on Monday, the 26th of September 2022 at 8.00 p.m. sharp at The Sweep Bar, Adamstown, Kilmeaden, Co. Waterford, Eircode X91 H588. New members or anyone interested in learning more about amateur radio or the group are as always very welcome to attend.

For anyone that wishes to find out more about the South Eastern Amateur Radio Group and their activities you can drop them an email to southeasternarg /at/ gmail.com or please feel free to go along to any of their meetings. You can check their website www.searg.ie and you can also join them on Facebook and follow them on Twitter.


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How Jake configures SDR# to listen to Encore classical music

Many thanks to SWLing Post contributor, Jake Brodsky (AB3A), who shares the following guest post:


How I Listen to Encore on Radio Tumbril

Listening to Classical music on shortwave is a challenge. It has loud and soft parts to the music. There may be selective fading. It isn’t a simple thing.

Also, configuring a software defined radio such as the highly configurable SDR# is not trivial. Note to readers: SDR# has been updated a lot recently and the noise reduction features are vastly improved. Kudos to Youssef Touil for all the hard work on this software. He continues to impress me with every update.

So I have some suggestions for those who are interested in listening:

First, get a decent set of over-the-ear headphones. Don’t rely on laptop speakers. They’re usually not designed for audio fidelity.

Set the radio for DSB reception with Lock Carrier and Anti-Fading checked. I also set the bandwidth to cover about 11 kHz or thereabouts.

On the Audio tab I uncheck the Filter Audio option. I’m going to rely on IF filtering to do my work for me.

Next, find an empty channel on the band where you will be listening to the program. Enable the IF Noise Reduction feature, set it to HiFi, and then set the threshold so that the noise floor is reasonably low. If you set the threshold too high, you’ll lose the higher frequency audio and there will be artifacts from the noise floor that I find unpleasant. A little bit of noise reduction is good, but more is not better.

I also enable the IF Filter/notch processing window to handle any stray birdies from switching mode power supplies. However, if not needed, I turn that feature off.

I turn off the AGC. And then I set the volume level to something reasonable, not too loud, not too soft, but just barely able to hear the noise floor.

Then I tune in the program. I was listening to the Sunday Evening (Monday 0200 UTC) broadcast from WRMI on 5950 kHz. There was some fading going back and forth. However, I took the atmospherics in stride, as if it were part of the experience. The broadcast from this evening
ended with the Pastoral Symphony from Beethoven. There were a few fades and there were a few swells, all due to atmospherics as the signal faded to the noise floor and emerged from it. But there was very little distortion. (thanks to the excellent engineers at WRMI).

The experience was actually sublime.

This is why I listen to shortwave broadcasts.

73,

Jake Brodsky, Amateur Radio Station AB3A

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Dan reviews the new Chameleon CHA RXL Pro Wideband Magnetic Loop Antenna

Many thanks to SWLing Post contributor, Dan Robinson, for the following guest post and review:


Photo by Chameleon

The Chameleon CHA-RXL Pro:  Improved Amp Board Raises the Game

by Dan Robinson

Back in 2021 I reviewed the CHA-RXL loop by Chameleon.  This loop antenna is sold by major retailers such as DX Engineering, Gigaparts and Chameleon itself – the company is a well-known name in antennas and other equipment for the amateur radio world.

I compared the CHA-RXL to Wellbrook 1530 and W6LVP loops feeding into a four-position Delta antenna switcher, and then to a Raven 16 port multicoupler which maintains good steady gain.

My Wellbrook is mounted on a telescopic mast about 15 feet above ground level, with a rotor.  The W6LVP (using LMR400 coax) is tripod-mounted with an overall height from ground of about 12 feet. It has special filters to prevent strong medium wave signals from bleeding into HF.

I have since added a UK-made loop (essentially a copy of a Wellbrook loop but smaller diameter and made of metal) combined with a W6LVP amp.  This W6 amp does not have filtering to block strong mediumwave signals.  In all, I have four loops into my Delta switcher, which feeds about two dozen receivers.

There is by the way quite robust discussion at https://groups.io/g/loopantennas about various loops, including the Chameleon.  And this past July, Steve Ratzlaff posted news about the upgraded loop amp board which will ship with what is now the CHA RXL Pro, saying:

“Chameleon has completely redone their CHA RXL loop amp board from the previous poor-performing loop amp that I tested some time back, and sent me one of the new production boards to test. I’m happy to say it tests very well especially for LF sensitivity, and I can now give it my “seal of approval”.  The new board is a version of the LZ1AQ loop amp.”

Photo by Chameleon

It turns out, according to an email from Don Sherman of Chameleon, that Steve is one of the engineers who helped design the new amp board for the CHA RXL Pro, and on the Loop Antenna group he provides a folder in which he placed previous test results with “new files of the new board (sweep of the new RXL Pro loop amp, and a picture of the new amp PCB).”

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Small Unidirectional Loop Antenna (SULA) Part 2: Construction Notes

Many thanks to SWLing Post contributor extraordinaire, 13dka, who brings us Part Two of a three part series about the new SULA homebrew antenna project. This first article describes this affordable antenna and demonstrates its unique reception properties. This second article focuses 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 Part 2:


Part 2: SULA Construction notes

by 13dka

The drawing [above] has all you need to know. You basically need to put up a symmetrical wire diamond starting with a balun at the one end and terminating in a resistor at the other end of the horizontal boom, the sides are supposed to be 76cm/29.92″ long so you need to make yourself some…

Support structure:

I used 0.63″/1.6cm square plastic square tubing/cable duct profiles from the home improvement market to make the support structure. You can use anything non-conductive for that of course, broom sticks, lathes… The plastic profiles I used had the advantage of being in the house and easy to work on with a Dremel-style tool and everything can be assembled using the same self-tapping screws without even drilling. The profiles are held together with 2 screws, for transport I unscrew one of them and put that into an extra “parking” screw hole on the side, then I can collapse the cross for easy fit into the trunk, a rucksack etc.

These profiles are available in different diameters that fit into each other like a telescoping whip. This is useful to make the support structure variable for experiments and to control the loop shape and tension on the wire. The booms end up at 1.075m each, the profiles come in 1m length, so that’s 4 short pieces of the smaller size tube to extend the main booms by 37mm on each side

On the resistor end of the loop that smaller tube isn’t mounted in the “boom” tube but to the side of it in order to keep the wire running straight from the balun box on the other side.

Mast/mounting:

You can use anything non-conductive to bring it up to height. On second thought that is indeed bad news if you were planning on putting that up on your metal mast…and we have no data on what happens when you do it anyway. I don’t know if the smallest (4m) telescoping fiberglass poles would suffice for portable operation, but I’m a fan of just using the big lower segments of my 10m “HD” mast for the stiffness they give me (3 segments for the height, the 4th collapsed into in the base segment for easy rotation). Telescoping masts also give you easy control over…

Height:

The published patterns are for 3m/10′ feedpoint height over “average” ground. Increasing height further has no expectable advantage, instead it will deteriorate the favorable directional pattern of the loop. Flying it lower, or even a lot lower in windy weather on the other hand is causing a surprisingly moderate hit on performance.

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