Category Archives: Mediumwave

Giuseppe upcycles and improves a homebrew MW antenna

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.

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.

Spread the radio love

Don Moore’s Photo Album: Santa Bárbara, Honduras

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

Spread the radio love

AWA Presentation: A History of British Broadcasting

BBC World Service – Bush House

The Antique Wireless Association/Museum recently posted another excellent presentation on YouTube; this time taking a look at the history of British Broadcasting. Here’s the description followed by the video:

Radio broadcasting in the UK followed a much different path than it did in the US, and there’s more to the story than the BBC. Tim Barrett tells the whole story in this history of British Broadcasting.

Click here to watch on YouTube.

If you enjoyed this presentation, consider becoming a member of the Antique Wireless Association at: https://www.antiquewireless.org/homepage/membership/

Spread the radio love

Radio physics explained: The Luxemburg-Gorky effect

Get it while you still can: The Luxemburg-Gorky effect

by 13dka

The Radio Luxembourg longwave transmitter Junglinster in the 1930s [RTL Group]


“In radiophysics, the Luxemburg-Gorky effect (named after Radio Luxemburg and the city of Gorky (Nizhny Novgorod)) is a phenomenon of cross modulation between two radio waves, one of which is strong, passing through the same part of a medium, especially a conductive region of atmosphere or a plasma.” (Wikipedia)

That sounds pretty abstract, right? In my own words, imagine your radio is tuned to a station on let’s say 162 kHz, 500 miles away. Somewhere in the middle between your receiver and the 162 kHz transmitter is a station transmitting on a different frequency, let’s say 234 kHz. The Luxemburg effect is that you can hear the modulation of the 234 kHz transmitter in the middle, on the 162kHz station you are receiving.  The effect is not depending that much on the frequency/wavelength though, the longwave station could affect medium wave stations and it has been created using shortwave frequencies far apart.

It was observed first in 1932, when listeners of the Swiss Beromünster 60kW medium wave station built just one year prior also heard a bit of Radio Luxemburg’s longwave transmitter (250kHz) on the Beromünster frequency (653kHz until 1934).  Of course this was assumed to be some kind of crosstalk within the receivers and probably drove radio engineers insane until 1933, when Bernhard D.H. Tellegen, a Dutch electrical engineer and inventor suggested the true origin of the effect: The new (1932) 150kW Radio Luxemburg longwave transmitter in Junglinster was directly modifying the ionosphere hundreds of kilometers above, it “heated” the ionosphere in a way that it made the plasma’s charge and reflectivity follow the amplitude modulation of Radio Luxemburg, thus modulating waves of other wavelengths crossing this part of the ionosphere.

Practical demonstration

Even if you’re living in Europe, you may never have witnessed that effect and according to this article by Paul Litwinovich, chances to observe this in the US are rather slim, due to the relatively low power of the stations.  I’m in Europe but never noticed it either – until recently: Continue reading

Spread the radio love

A review of the Tecsun H-501x portable shortwave radio receiver

I was recently searching for my review of the Tecsun H-501x on the SWLing Post to send to a reader when I realized I had not yet published it here! Let’s fix that…

The following review of the Tecsun H-501x was originally published in the November 2021 issue of The Spectrum Monitor magazine. Enjoy:


A review of the Tecsun H-501x

by Thomas (K4SWL)

Last year [2020], we were treated to a group of new shortwave portables from Tecsun:  the PL-990, PL-330, and the H-501.

Although all of these models garnered attention from shortwave listeners, one model in particular seemed to draw the most interest, the Tecsun H-501.

No doubt, much had to do with the H-501’s size––a large format portable––and especially the twin stereo speakers, that no doubt sparked the interest of those of us who owned (or wished we owned) the venerable Grundig Satellit 500 or 700 with its reputation for robust audio.

Tecsun was also very clear during their product announcement in 2019 that the H-501x is the flagship portable for the Tecsun line.

H-501 versus H-501x

Note that the product being evaluated in this review is the H-501x; the latest “export” version of the H-501.

The differences between these two models is fairly modest. The “x” model gives the user a slightly lower frequency floor in longwave and shortwave, and finer FM tuning (50 kHz as opposed to 100 kHz) when the AM tuning steps are set to 9 kHz as opposed to 10 kHz.

The differences are so modest between the H-501 and H-501x, I wouldn’t be worried if you already have the H-501. I would simply encourage you to only purchase from a reputable Tecsun distributor so you can be confident you’re not receiving one of the very early production runs of the H-501 that was only distributed domestically within China. Some of these early domestic models didn’t have all the refinements of the latest H-501 versions. I would encourage you to only purchase the H-501 or H-501x from a reputable distributors like Anon-Co, Waters and Stanton, Tecsun Radios Australia, and Bonito.

Unique features

Besides the large dual speakers of the H-501x, there are a number of other unique features and design choices that truly set the H-501 series apart from other Tecsun models.

 

Firstly, the H-501x uses two 18650 Lithium Ion batteries housed in two separate battery compartments. Both batteries can be internally charged, but here’s the interesting part: each battery seems to be somewhat independent of the other. When you engage battery charging, you must select, via a mechanical switch on the back of the radio, “Battery A” or “Battery B.” Only one battery can be charged at a time, and thus only one will power the radio at a time.

More than once, I’ve been listening to the H-501x and the battery indicator started flashing, signifying a low battery. I simply switched the battery switch to Battery B, and, voliá:  I have a full battery again! This reminds me of a college friend’s VW Beetle that had a spare fuel tank…with this unique feature, when you were running low on fuel, you’d kick in the spare fuel tank and then make plans to refuel the main tank soon. Of course, with the H-501x, both these “fuel tanks” are also generous ones, in that the batteries last for a good while.

I find that the play time of each battery impressive given the size and audio amplification used in the H-501x. I had worries that the unit’s need for two batteries could suggest a short battery life, but fortunately this hasn’t been the case, no matter what mode I’ve used (FM, AM, shortwave, or Bluetooth).

However I will note here that the supplied switching power supply will inject noise if you try listening to AM or shortwave while charging. This hasn’t affected FM reception, though.

The fold-out metal bail on the H-501x is very large. This shouldn’t have surprised me, but it did. The H-501x is tall and wide, but not very deep––only marginally deeper than, say, the PL-880. The bail needed to be low-profile, but also support this mini “wall” of the radio while in use. The metal wire bail is handy and certainly does the trick, although there’s only one tilt position, and when it’s deployed, the radio effectively has a large footprint. This might limit where you can set it if the surface––say, a bedside table––is small. Not a problem for me, but worth noting. Continue reading

Spread the radio love

Don Moore’s Photo Album: Ecos del Torbes

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


Don Moore’s Photo Album

by Don Moore

Introduction

When I discovered DXing over fifty years ago I also discovered the world. Through my ears I traveled to other countries and explored other cultures. But DXing has also literally taken me places. My early interest in Latin American DXing developed into a broader interest in Latin America. That led to me joining the Peace Corps after college and working three years in Honduras. That experience furthered my interest in Latin America and I have continued to travel in the region whenever possible. For me DXing and travel were always intertwined. I’m one of a handful of hobbyists who took DXing beyond just listening and went knocking on broadcasters’ doors to visit the distant stations I heard. My ex-wife dubbed this ‘door-to-door DXing.’

To date I’ve visited over 150 radio stations in thirteen countries. A few were medium-wave or FM only, but I was always most interested in visiting broadcasters that used shortwave, either at the time of my visit or a few years before. As my station visits were primarily made in the 1980s and 1990s, almost all of the stations are long-gone from the shortwave bands. However, many are still around on medium wave and FM and often also via streaming on the Internet. As much as I miss the magic of shortwave I know that these stations reach more listeners today via streaming than they ever did with their low-powered shortwave transmitters. Honestly, I sometimes enjoy tuning them in without the fading and static of shortwave. But the memories of what shortwave once was are still there.

Photos also bring back memories. I took dozens of pictures on my station visits and enjoy scrolling through them now and then. You may have seen some of them. Many of my photos were printed with articles I wrote for various DX publications and I’ve done a few slide-shows at DX get-togethers over the years.

In this series of columns I want to share my old photos once again. If you’ve been DXing as long as I have maybe they’ll bring back memories of what you once heard. And if you haven’t been around that long you will have a better understanding of the good old days we oldtimers talk about.

Ecos Del Torbes

There is no better place to start this journey than with Ecos del Torbes. Using ten kilowatts on 4980 kHz, this Venezuelan broadcaster was possibly the most consistent station in the sixty-meter band throughout the 1970s, 80s, and 90s. If you were DXing the tropical bands during those years you surely logged them a few times. If you were lucky you may even have heard their one kilowatt signal on 9640 kHz. They were a very good verifier and for many DXers Ecos del Torbes was among the first Latin American stations QSLed.

Just after Christmas in 1994, my then-wife, four-year-old daughter, and I flew to Mérida in western Venezuela for a family vacation. For ten days we had a great time in this Andean city and then Theresa and Rebecca returned to Iowa while I stayed another week to visit radio stations. I was also getting paid by the Voice of America to research and write a study on the media scene in Andean Venezuela. The now very-out-of-date report can be read at my Patepluma Radio website (which hasn’t been changed in over twenty years and is in need of a facelift).

In that week I visited fifteen radio stations in six towns and cities and Ecos del Torbes was the highlight. I arrived at their doorstep unannounced but was immediately treated as an important guest. I was given a great tour and even got to sit in on a live newscast to see the famous Venezuelan doorbell being used live. I was there about ninety minutes and then walked a block up the street to sister station Radio Táchira. Their facilities were smaller but that’s where the technical offices were and Chief Engineer Ivan Escobar had been told to expect me. Ivan gave me a tour and invited me to visit the Ecos del Torbes transmitter site with him in the afternoon. On the way we stopped by his house where his wife had lunch waiting for us. Visiting Ecos del Torbes was not just the highlight of this trip but ranks as one of my all-time favorite station visits. These pictures bring back many good memories.

Photos

Ecos del Torbes was located in the second floor of this building in downtown San Cristóbal. The entrance was the door on the side.

The small plaque next to the door was easy to miss. I walked right by the first time.

Edgar Fabala of the news department showed me around. Here he demonstrates the mini-xylophones that Venezuelan stations used to make the distinctive ‘doorbell’ sound that separated items in the news reports.

Announcer in the studio preparing to read the news.

The adjoining control room.

Ecos del Torbes had one of the largest record libraries in Venezuela. The LPs were color-coded by type.

Julio Achila was a control room operator who had worked at the station since it opened in 1947.

This pennant was considerably larger than the ones sent to DXers.

Sister station Radio Táchira was located a block up the street on the fourth floor of this building.

The Ecos del Torbes transmitter building.

The 50 kilowatt medium wave transmitter on 780 kHz.

Chief Engineer Ivan Escobar and Don Moore next to the 31 meter transmitter. The larger transmitter was for the well-heard 4980 kHz frequency.

The antenna array used for 4980 kHz. The medium wave tower is in the background.

Dipole antenna used for 9640 kHz.

San Cristóbal once had a third broadcaster on shortwave. Radio San Sebastian used 6070 kHz in the early 1970s. (They were not affiliated with Ecos del Torbes).

That was nearly three decades ago and a lot has changed. Ecos del Torbes and Radio Táchira have been gone from shortwave for over twenty years.

In 1995 Ecos del Torbes was at the corner of Calle 9 and Carrera 8, the same address as when I first QSLed them in 1972. Sometime since my visit they moved an outer neighborhood about two kilometers to the east. To find the new offices locate San Cristóbal on Google maps and then search for “Grupo Radial Gonzalez Lovera”. The transmitter site is still where I visited it and can be seen by plugging the coordinates “7.7885, -72.2725” into Google maps and switching to satellite view. (Ignore the picture that pops up to the side. That’s not it.) Zooming in, the medium wave tower is clearly visible but there are no signs of the old shortwave antennas. I suspect they were sold for scrap years ago. I never have found out where the Radio Táchira transmitter site was.

I’d love to go back to Venezuela someday and see some of the other cities that I used to listen to, such as Barquisimeto, Valencia, El Tigre, and Sucre. Unfortunately the political and economic situation there doesn’t look good and it doesn’t look as if it will improve any time soon. But when it does, I’ll be back.


Click here to check out all of Don Moore’s Photo Album columns. Each new article will appear on the SWLing Post home page/feed and in this link.

Spread the radio love

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.

Continue reading

Spread the radio love