Category Archives: Guest Posts

Video: Giuseppe’s “Cassette Loop” on the shortwaves with induction

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

Dear Thomas and Friends of the SWLing Post,

I’m Giuseppe Morlè from central Italy, Formia on the Tyrrhenian Sea…

My Cassette Loop experiment this time shows how induction takes place on short waves after medium waves.

I used a smaller box as the primary antenna which, however, is pushed by the secondary one due to the induction effect generated between the two windings brought closer together.

This way, the larger loop “captures” more of the signal and sends it to the smaller cassette…

I really like working on induction… I hope you like it:

Click here to view on YouTube.

Thanks and greetings from central Italy.
73. Giuseppe Morlè iz0gzw.

Thank you so much for sharing this, Giuseppe!

DIY on Shortwave

Tom’s Recommendations: Earbuds and EQ Settings for Shortwave Listening

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

Earbuds for Shortwave Listening

by TomL

A few years ago I had bought the discontinued Sennheiser MM 50 earbuds for a cheap price on Amazon to use in my various radios. The portable radios in particular can use more fidelity because of their small, raspy speakers. I also like to listen without bothering others around me who might not want to listen. And earbuds are a LOT more comfortable for my ear lobes than any over-the-ear headphones I have ever used. Furthermore, the old Apple iPhone 4 earbuds were very harsh to listen to. However, a trade-off is that, generally, earbuds are somewhat fragile; one of the two pairs of MM50’s died through mishandling.

I was generally happy with them while listening to Shortwave broadcasters with a mix of news/talk and music. I especially liked them on Mediumwave listening; stations can sound surprisingly good when playing music. Then I tried using these earbuds on my Amateur Radio transceiver, a Kenwood TS-590S. I was impressed how clear they sounded with a lack of distortion, although there was too much bass. Fortunately, Kenwood supplies USB connected software with an TX & RX 18 band EQ (300 Hz spacing, not octaves).

Here is a frequency response chart I found from Reviewed.com for this model:

One of the notable things about these earbuds is the total lack of distortion. Most likely one of the reasons they sound so clear on Shortwave, which has many LOUD audio spikes.

I had not wanted to get Bluetooth earbuds. However, I had recently upgraded my cell phone and NO headphone jacks anymore! So, while I do not use Bluetooth yet for radios, I can see a time in the future to get a Bluetooth transmitter to plug into a radio with a headphone jack. I am reluctant since I do not like having to recharge my earbuds and I put in a lot of radio listening time. Am I supposed to buy two Bluetooth earbuds and swap while charging? Maybe in the future. And also, am I supposed to buy a Bluetooth transmitter for every non-Bluetooth radio I own? Not likely gonna happen.

In the meantime, I ordered cheap wired earbuds from Amazon. I had a $5 credit for trying Prime, so when I saw these Panasonic ErgoFit wired earbuds (RP-HJE120-K) for slightly over $10, I said to myself, “why not?”. Supposedly wildly popular, they are one of the most rated products on all of Amazon with 133,821 ratings/opinions (perhaps Russian bots?!?!?).

Here is a frequency response chart from ThePhonograph.com for these Panasonic earbuds:

You can see comparatively that the bass response in the very good Sennheiser MM50’s is much stronger, being good music earbuds. But for voice articulation, not as much, even though they have no distortion. The Panasonic ErgoFit’s have more modest bass, less of a dip in the lower midrange audio frequencies, and more importantly, has a peak near 2500 Hz and its harmonic 5000 Hz. The highest highs are also modest compared to the Sennheiser model. This general frequency response to “recess” the bass and treble frequencies and peak the 2500 Hz is very useful for voice intelligibility.

As described by the famous speaker-microphone-sound-system maker, Bob Heil relates what he learned from the scientists at Bell Labs many years ago. Speech intelligibility is enhanced when audio is compensated for our natural human hearing. Equalizing below 160 Hz, reducing the 600-900 Hz region, and peaking the 2000-3000 region centered at 2500 Hz will increase intelligibility dramatically. The story goes that Bell Labs was tasked by parent AT&T with finding out why the earliest phones in the 1920’s sounded so muffled and hard to understand. After many experiments, the scientists found the most important frequencies for our ears + brain to comprehend speech. In other words, our ears are not “EQ-flat” like a scientific instrument is. Continue reading →

Don Moore’s Photo Album: Santa Bárbara, Honduras

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

Don Moore’s Photo Album: Santa Bárbara, Honduras

by Don Moore

I first set foot in Latin America in January 1982 when I arrived in Tegucigalpa to begin three months of Peace Corps training. Three months later I moved to my Honduran home, the town of Santa Bárbara in the western mountains. For the next two years I worked as a teacher and resource person at the Escuela Normal Mixta de Santa Bárbara, a specialized high school that trained its students to teach primary school.

Santa Bárbara had a shortwave station, La Voz del Junco on 6075 kHz but it was rarely reported because it broadcast irregularly and was usually blocked by big international broadcasters when it was on the air. I had never heard it but I met Miguel Hasbun, the owner-manager, on my first visit to Santa Bárbara when he picked me up hitchhiking north of town. He told me that the shortwave transmitter had been broken down for a while but that he was going to fix it ‘soon’. Over the next year I kept inquiring about the shortwave and he finally did fix it. After that the station broadcast irregularly for the next year or so, mostly in the morning. I served as volunteer veri-signer and issued around fifteen QSLs. I even issued one to myself.

Santa Bárbara had one other radio station, Ondas del Ulúa on 1140 kHz medium wave (later 1150 kHz). They also announced 4770 kHz shortwave in their canned IDs and station staff assured me they would be adding shortwave “soon”. It never did happen but the WRTH did list the frequency as future plans for several years.

Audio:

Ondas del Ulúa 1982 sign-off announcement mentioning 4770 kHz.

The department of Santa Bárbara had one other radio station, Radio Luz y Vida on 1600 and 3250 kHz in the town of San Luis. The founder, manager, and veri-signer for Radio Luz y Vida was a missionary from Oklahoma named Don Moore. Needless to say, this caused a lot of confusion in the DX world as some people assumed he and I were the same person. On the map, San Luis is only about thirty kilometers from Santa Bárbara but getting there involved a five-hour journey on two buses. I only went once and the other Don Moore was out of town, so I never met him. I did meet two nurses who were working at the mission’s health clinic.

Photos

These pictures were all taken in 1982 to 1984 while I lived in Santa Bárbara [click on photos to enlarge].

La Voz del Junco’s yellow sign on main street in downtown Santa Bárbara. The small tower on the left was the corner of what had been an army post but was being used as a regional prison in the early 1980s. I once went there every day for a week to supervise student-teachers doing adult literacy classes for the inmates. It was not a pleasant place to be.

Entrance to La Voz del Junco. The girl is examining a poster for the night’s showing at the makeshift movie theater that Don Miguel operated nearby. Continue reading →

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

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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.

Frank reports on the Deshibo RD1860BT portable shortwave receiver

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Many thanks to SWLing Post contributor, Frank, in Germany, who shares the following guest post and review of the Deshibo RD1860BT:

Deshibo RD1860BT report

Hello Thomas,

Today I would like to report on a new portable world receiver. Unfortunately, new devices have not been found on the shelves of electronics retailers for a long time, but now in the depths of the world wide web. And that’s how I came across the Deshibo RD1860BT.

Deshibo is certainly known to many from their GA450 loop antenna. But Deshibo has also produced several radios, including the RD1780L, which is probably a little better known. New to the segment is the RD1860BT, which initially seemed like an old friend to me. An Eton Elite Executive? Yes, there are external similarities, but also differences.

Many months ago I had an Eton Elite Executive for a short time. I had heard of its excellent reception properties, which I can confirm, but the design is reminiscent of older receivers from the 80s, is relatively heavy, operation is sometimes a bit cumbersome, the protective cover does not protect properly. I find the device to be portable overall difficult. We didn’t become friends, so I sold it on to a Swede, who in turn became a friend.

I still missed the Eton. RDS on VHF is not found in any Tecsun , nor are there memory banks that can be written on.

Then I discovered the RD1860BT and couldn’t resist. First of all: the Deshibo is only labeled in Chinese for important function keys. But the friendly dealer on eBay provided me with an English manual before I bought it. That was the deciding factor, because I was sure that after a little use , the Deshibo could be operated blindly.

However, some questions have arisen in the user manual. Some things didn’t seem quite right, others were completely missing from the description. That’s why I decided to write my own manual on a journey of discovery of the new Deshibo. And so that it might also help others who might be interested in radio, I wrote it in English and attach it here.

Click here to download Frank’s version of the RD1860BT manual (PDF).

The Eton’s somewhat unsorted manual was very helpful, but I also added my own drawings. For example, I added an English-labeled keyboard as a back cover, so that the keys can be assigned without a long search.

Here you can already find the first differences to the Eton: the keyboard layout is a bit more orderly. Also, the Deshibo doesn’t have a metallic speaker grille (which frankly I don’t like about the Eton). The display, not the writing, is backlit in orange on the Deshibo . Most importantly, the Deshibo is a lot lighter than the Eton ( around 500g if I researched correctly). And that means: the structure of the Deshibo must be different. Continue reading →

Guest Post: Monitoring Digital Selective Calling (DCS) with YADD

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

Monitoring DSC with YADD

By Don Moore

(The following article was originally published in the April/May 2022 edition of the Great Lakes Monitor, bulletin of the Michigan Association of Radio Enthusiasts. An all-band listening club, MARE publishes a bi-monthly print bulletin and a weekly e-mail loggings tip-sheet. The club also holds regular get-togethers, picnics, and DXpeditions, generally in southeastern Michigan.)

There are dozens if not hundreds of different digital modes used for communication on the MF and HF bands. These aren’t broadcasts you want to listen to unless you like to hear weird tones, beeps, warbles, and grinding noises interspersed with static. Digital modes are for monitoring, not listening. And monitoring them requires having software that does the listening for you and converts the noises into something meaningful – like the ID of the station you’re tuned to. The learning curve to DXing digital utilities can be steep. There are lots of modes to identify and the software can be complicated to learn. Some broadcasts are encrypted so you can’t decode them no matter how hard you try. But the reward is lots of new stations and even new countries that you wouldn’t be able to add to your logbook otherwise.

One of the easiest digital modes to DX is DSC, or Digital Selective Calling. DSC is a defined as “a standard for transmitting pre-defined digital messages.” Look online if you want to understand the technical specifications that specify the values, placement, and spacing of the tones. The result of those specifications is a string of three-digit numbers like this:

125 107 125 106 120 105 120 104 000 120 022 120 041 000 002 022 020 041 108 002 053 020 080 108 006 053 021 080 070 006 118 021 126 070 126 118 126 126 126 126 126 126 126 126 126 126 117 126 112 126 117 117 117 112 109 125 108 125

Each three-digit value represents either a digit or a key word and the positions of the values map to the various fields contained in the message. This message, which was received on 8414.5 kHz, is a test call from the tanker Brook Trout to the coastal station Coruña Radio in Spain. The sender and destination are not identified by name but rather by their nine-digit MMSI (Maritime Mobile Service Identity) numbers – 538006217 for the vessel and 002241022 for the coastal station.

GETTING STARTED WITH DSC

Logging DSC stations requires three pieces of software. First you need a decoder program that turns the noises into numbers and the numbers into meaning. There are several free and commercial options but the most popular one for beginners is YADD – Yet Another DSC Decoder. YADD is free and easy to set up and while YADD can be used by feeding the audio from a traditional radio into your computer, the most common use is with an SDR. That’s what I use and what I will describe here.

Second you need an SDR application and an SDR. I prefer HDSDR for most of my SDR use but I like SDR-Console for digital work. But any SDR program will work if you can feed the audio to a virtual audio cable. And that’s the final thing you need – a virtual audio cable to create a direct audio connection between your SDR application and YADD. There are several different ones available but I recommend VB-Cable. Your first VB-Cable is free and that is all you need to run a single instance of YADD. If you want to expand you can buy up to four more cables from them later. Continue reading →