Tag Archives: shortwave

A “knobs and switches” oldster investigates the SDRplay RSPdx . . . Wow!

By Jock Elliott, KB2GOM

It is hard to imagine a less spectacular looking piece of radio gear than the SDRplay RSPdx. It is literally a black box. Aside from the printing on top of the box, the most exciting thing about the RSPdx are the two red plastic covers on the antenna connectors on the side. There are no switches, no knobs . . . you can’t do anything to it except connect an antenna (or antennas) on one side and a USB cable on the opposite.

But once you connect the USB cable to your laptop and fire up the SDRuno software (that you have previously downloaded and installed), you are now in command of a listening post that covers from 1 kHz to 2 GHz.

We’ll get to the important stuff in just a minute, but first a little background.

For an oldster retrocrank like me, a proper radio has knobs and switches . . . preferably a knob or switch for every job. Lately, however, I have noticed that a lot of DXers and ordinary listeners are reporting good success with SDRs – software-defined radios. So I started to wonder about them.

There are three elements to a software-defined radio like the SDRplay RSPdx: the SDR box itself, which is the part of the system that actually receives the radio signals; a Windows computer (laptop or desktop), which provides the command and control for the SDR; and whatever antennas are required to receive the signals that the listener would like to hear. And, just to be absolutely clear, you need all three elements for the SDR system to work at all.

With my curiosity about SDRs rising, I inquired of Thomas, SWLing’s Maximum Leader, whether SDRplay – one of SWLing Post’s sponsors – might like me to take a look at one of their SDRs. Their answer was an emphatic Yes, and I had an RSPdx in my hands just a couple of days later at no cost to me or the SWLing Post.

I have to admit I had some trepidation about the process of bringing the RSPdx online because any time you have three different elements from three different sources that must work together for a system to function properly, there is always the possibility that some of the elements might not “play well together.”

Installation is easy and fast. Connect the RSPdx to the computer using a USB A-male to B-male cable (which the user must supply; often called a printer cable), then connect the antennas using the appropriate cable. In my case, I connected an MFJ 1886 Receive Loop to the Antenna C connector and an off-center fed dipole to the Antenna A connector.

To SDRplay’s great credit, they have produced an excellent video for first-timers and folks not familiar with SDRs — https://youtu.be/Oj_-dOLVzH8 . I recommend watching it, perhaps a couple of times, before you get started.

When you first fire up the SDRuno software, you will see the main panel:

Click on the “RX” button, and the Receive panel will be displayed. After you slide it over, it will look something like this:

Click on SP1 or SP2 in the main panel, and one of the peak displays will appear:

Finally, click on the PLAY button in the main panel, and whatever frequency you have selected will begin to play. Continue reading →

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

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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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A DXpedition to East Sandy

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Many thanks to SWLing Post contributor, Don Moore–noted author, traveler, and DXer–for the following guest post:

A DXpedition to East Sandy

By Don Moore

When I was in college over forty years ago, seven of us had a small DX club in central Pennsylvania. A couple of times a year we would gather at the house of one of our parents for an all-night DX session. We shared tips and ideas, had fun, and always heard some new DX. Good DX can happen anywhere if conditions are right and most of mine over the past fifty years took place at wherever home happened to be at the time. But most of my best experiences and best memories of DXing were not made at home. They were made by getting together to DX with other hobbyists such as we did back in college.

Nowadays when I get together to DX with other hobbyists it’s to go on a DXpedition, which is nothing more than taking your receiver to a place where DXing will be better than at home because there’s less noise and you can erect better antennas. Simple DXpeditions can be done from cars. My old friend Dave Valko used to go on what he called micro-DXpeditions. He drove to a remote spot in the mountains not far from town, laid out a few hundred feet of wire, and then DXed from his car for a couple hours. He frequently did this around dawn and around sunset and got some great DX. I know several other DXers that do this today, either at countryside locations or in large parks.

I’ve done micro-DXpeditions a few times. It’s fun but it always lacks an important element: other DXers. For me, the best DXpeditions aren’t just about hearing interesting stuff (although that is very important). They are also about sharing the hobby with other interested friends. And the best way to do that is to go on a real DXpedition with them.

For three years in a row prior to the pandemic a group of eight of us had rented a lodge in rural central Ohio for an annual DXpedition. Covid shelved our plans for 2020 but by the summer of 2021 we were all looking forward to a fourth DXpedition in September. Then another wave of covid swept across the country and we canceled a few weeks before the event. Fortunately, the worst of those days are behind us and we finally had our fourth DXpedition the first week of October of this year. Unfortunately, only five of us could make it – Ralph Brandi, Mike Nikolich, Andy Robins, Mark Taylor and I.

For four nights our DXpedition home was the same place in western Pennsylvania that we had canceled at in 2021. The location was a rural house on the bluffs overlooking the Allegheny River near the old East Sandy railroad bridge (now a hiking trail). It’s always a gamble going to a new place chosen solely based on the AirBnB listing and other information found online. But this site had all the appearances of being a good place to DX from. The pictures and Google satellite view showed that there were trees around the house and large nearby open fields surrounded by woodland. The terrain was relatively flat when viewed on 3D satellite view. We would have plenty of space for a variety of antennas. Furthermore, it didn’t look to be a noisy location. The nearest neighbor was over a quarter mile to the south and because the house was the last one on the road that powerlines stopped at the driveway. I couldn’t have done much better if I had designed the location myself.

Our DXpedition home. Coordinates 41°19’23″N 79°46’08″W (Don Moore)

ANTENNAS

Good antennas are the most important part of any DXpedition and erecting them is usually the most time-consuming part of set-up. Still, you never really know what’s going to fit until you’re there. I arrived at 2 p.m. and Mark pulled in a few minutes later. We immediately walked the grounds and were pleased with what we saw. Ralph arrived while we were laying out the first antenna. Mike and Andy arrived later in the afternoon in time to help finish up.

Our DXpedition antenna farm consisted of two delta loops, a DKaz, and two BOGs. The delta loops used Wellbrook ALA-100LN units and are as I described a few years ago in my article on radio travel. These are easy to erect and are good all-around antennas for anything below 30 MegaHertz. The DKaz (instructions here) is a rather complex-to-build antenna designed for medium wave. Ralph uses one at home which he had taken down for the summer to make yard work easier. He brought the pieces and put it up by himself. The two BOGs (Beverage-on-the-ground) were a 300-meter wire to the northeast and a 220-meter wire to the north. Beverages are good for long wave, medium wave, and the lower shortwave frequencies. Continue reading →

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In search of the unique, the weird, the unusual . . . a reader participation post

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By Jock Elliott, KB2GOM

There is a richness in human experience, and I want to sample it.

When I worked the world on the HF ham bands, I considered myself a “conversation hunter.” I wasn’t content to simply make a contact, exchange signal reports, and move on; I wanted to talk to people in foreign lands, to chat with folks who did unusual things, to hear things you would not normally hear otherwise.

Here’s a quick sampling:

I spoke with a ham in England, a falconer, who flew the birds for the movie “Lady Hawke,” and who had a side business of manufacturing tiny transmitters that falconers could use to track their birds.
The chief groundskeeper for a major university in Ohio once explained, on ten meters, the difference between commercial and consumer lawn mower engines (the commercial units are designed to be rebuilt quickly and easily).
Recently, on 2 meters I heard a ham explain how he used VHF/UHF crossband repeat to provide coverage for a special event.

Similarly, I enjoy hearing the unusual on the AM, FM, or shortwave broadcast bands. For example, one evening years ago, on shortwave I heard “Radio Peace and Love” from somewhere in the Caribbean, followed (on another frequency) by “Mark from Michigan” extolling the militia movement. On another occasion, I heard a story on Radio New Zealand about a Maori weaver’s collective.

So, bottom line, I am interested in the unique, the unusual, the weird (could be all three!) . . . and I prefer stuff that is NOT syndicated across a bunch of stations. Marion’s Attic comes to mind as I write this.

So, now it’s your turn: what’s your favorite programming that is off the beaten path? Please respond, and be sure to mention the time and frequency when it might be heard.

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Giuseppe upcycles and improves a homebrew MW antenna

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Many thanks to SWLing Post contributor, Giuseppe Morlè (IZ0GZW), who shares the following:

Dear Thomas and Friends of SWLing Post …

This is Giuseppe Morlè. As always, I try recycling what I have and improving upon antennas I’ve built in the past. This is one way we radio lovers can experiment. Many years ago, I made an antenna only for medium waves; by adding a circuit, I can now listen to short waves.

I took advantage of a small frame that I recovered from an old commercial FM / AM stereo receiver by removing its coils for medium waves and I wound around it only two coils sufficient to have a frequency range from 3.5 to 18 MHz.

I remember that the antenna in question also receives medium waves as it was born.

I chose this small frame because I wanted everything to be small in order to carry this compact antenna everywhere.

Unlike my other projects for SW and MW, which have a cable that carries the SW signal to the receiver, this time I used the induction that is created around one end of the loop, which I spiraled to get inside the stylus of my Tecsun PL-660 and which then transfers the signal to the receiver.

I did some tests on my balcony the day after a strong storm and I noticed that the propagation was absent but I still wanted to make sure that everything was working.

[Note that you can translate this video into your language via YouTube’s automatic subtitles. Click here to learn how to do this.]

I will keep you updated on other tests on more favorable days of propagation … I still invite you to follow me on my Youtube channel.

I wish everyone a good listening …
73. Giuseppe Morlè iz0gzw.

Many thanks, Giuseppe. I, for one, love all of your homebrewed and recycled antennas. This one is no exception! What a fun project. I love how you use what you have and aren’t afraid to experiment! Thank you for sharing.

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High-Frequency Trading Service: FCC posts two lobbying documents by DPA Mac

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Many thanks to SWLing Post contributor, Benn Kobb (AK4AV), who notes that the FCC has posted for public inspection two lobbying documents by DPA Mac, applicant for a new DRM HF broadcast station with 2 kW of transmitter output power.

Benn notes:

“Regardless of DPA’s claims that its broadcasts will be free of charge and not encrypted, its non-broadcast high-frequency trading service will be for paying customers only.

“That is the purpose of this station and is why its target areas, as seen in a world map slide, are limited to the location of certain foreign exchanges. This despite its claim to be a worldwide service.

“There is little profit in SW broadcasting today, and what business there is available is accommodated by those existing US HF stations that can hang on through economic shifts. No, the DPA Mac station is not devoted to global information as a business venture. It wants a license to provide private telecommunications. The broadcasts to the public are just so it can get licensed, because there is no other radio service in the HF spectrum for private international data links.

“At this time no one knows what the FCC will do with this license application and two other similar applications. What is clear is that the applicants want to get on the air ASAP before any possible changes that may affect the HF broadcasting service.”

The FCC posted the following documents in an accessible place on their website yesterday morning:

https://www.fcc.gov/ecfs/document/1110171119378/1

https://www.fcc.gov/ecfs/document/1110171119378/2

Thank you for the update, Benn.

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Radio Waves: QSL Book, Ham Radio in Taiwan Civil Defense, Radio Silence in Venezuela, and ARRL Handbook 100th Edition

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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!

New Book: QSL? (Do You Confirm Receipt of My Transmission?) (Standards Manual)

A collection of over 150 “QSL cards”, QSL? chronicles a moment in time before the Internet age, when global communication was thriving via amateur, or “ham”, radio operators.

Discovered by designer Roger Bova, the distinctly designed cards follow the international correspondence of one ham, station W2RP, who turned out to be the longest-standing licensed operator in The United States.

Click here to read more.

If China declares war, these ham radio enthusiasts could be crucial (LA Times)

TAIPEI, Taiwan — On Tuesday nights, BX2AN sits near the Xindian River, motionless but for his thumb and middle finger, rhythmically tapping against two small metal paddles. They emit a sound each time his hand makes contact — from the right, a dit, or dot; from the left, a dah, or dash, the building blocks of the Morse code alphabet.
“Is anyone there?” he taps.

The replies come back in fits and starts: from Japan, then Greece, then Bulgaria. Each time, BX2AN, as he is known on the radio waves, jots down a series of numbers and letters: call signs, names, dates, locations. Then he adjusts a black round knob on his transceiver box, its screens glowing yellow in the dark.

There can be no doubt that this is his setup. That unique call sign is stamped across the front of his black radio set, scrawled in faded Sharpie on his travel mug and engraved in a plaque on his car dashboard. On the edge of his notepad, he’s absent-mindedly doodled it again, BX2AN.

In the corporeal world he is Lee Jiann-shing, a 71-year-old retired bakery owner, husband, father of five, grandfather of eight and a ham radio enthusiast for 30 years. Every week, he is the first to arrive at this regular meeting for Taipei’s amateur radio hobbyists.

[…]The self-governing island, about 100 miles east of China, is weighing wartime scenarios in the face of growing military aggression from its vastly more powerful neighbor. If cell towers are down and internet cables have been cut, the ability of shortwave radio frequencies to transmit long-distance messages could become crucial for civilians and officials alike. [Continue reading…]

Radio silence grows in Venezuela as government shutters dozens of stations (Reuters)

CARACAS, Oct 26 (Reuters) – In July officials from Venezuela’s telecommunications regulator entered the Moda 105.1 FM radio station, in the northwestern state of Cojedes, accompanied by members of the national guard and demanding to see all the station’s licensing.

Hours later they stopped it broadcasting – making Moda one of at least 50 stations in Venezuela’s interior which have been closed so far this year by the Conatel regulator because it says they lack valid licenses.

The accelerated closures are a new step in efforts by the government of President Nicolas Maduro to control information and give state media hegemony over communications, journalist guilds and non-governmental organizations say, continuing a policy begun under his predecessor Hugo Chavez. [Continue reading…]

The ARRL Handbook for Radio Communications100th Edition (ARRL)

We have arrived at a milestone. The 100th edition of The ARRL Handbook for Radio Communications is here: Handbook 100. How do you celebrate the most widely used one-stop reference and guide to radio technology principles and practices? By continuing to fill the pages of another edition with the progress and achievement of radio amateurs. Handbook 100 is written for everyone with a desire to advance the pursuit of wireless technology. Here is your guide to radio experimentation, discovery, and innovation.

What’s Inside

Each chapter is filled with the most up-to-date knowledge representative of the wide and ever-expanding range of interests among radio amateurs. There are practical, hands-on projects for all skill levels — from simple accessories and small power supplies to legal-limit amplifiers and high-gain antennas.

Key topics:

Radio electronics theory and principles
Circuit design and equipment
Signal transmission and propagation
Digital modulation and protocols
Antennas and transmission lines
Construction practices

Updated with new projects and content, including:

An all-new chapter on radio propagation covering a wide range of bands and modes
New and updated sections on electronic circuit simulation
New cavity filter and high-power HF filter projects
New coverage on digital protocols and modes
New material on RFI from low-voltage lighting and other sources
Revised sections covering new RF exposure limits
New content on portable station equipment, antennas, power, and assembly
New material on ferrite uses and types
New section on how to use portable SDR to locate sources of RFI …and more.

Click here for more information and to place an order.