Category Archives: Guest Posts

Radio Reloj, Costa Rica (1990)

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

Don Moore’s Photo Album: Costa Rica (part one)

by Don Moore

Costa Rica is one of the most visited countries in Latin America. I only visited there once, for three weeks in May-June 1990 when the country was just beginning to become a major international eco-tourism destination. Visitors were few and prices very affordable. Except for a short trip to the Monteverde cloud forest, we spent all our time in the central valley, staying in San José and nearby Heredia. Rather than nature, our visit focused on cultural and historical sites … and a lot of radio stations.

Since the 19th century, Costa Rica has been one of the most literate and educated countries in Latin America. That quality is reflected in its radio broadcasting industry, which has always been very professional. Curiously that’s even reflected in station verifications. Almost every Costa Rican shortwave station that I’ve verified had a professionally printed QSL card.

Despite being one of the smallest countries in Latin America, Costa Rica had a lot of shortwave radio stations. I have fifteen in my logbooks and some of the most famous ones were already off the air when I started DXing. Unfortunately, shortwave broadcasting from Costa Rica ended almost twenty years ago so there’s no more to be had. It is still possible to log Costa Rica on medium wave but it’s not as easy as it once was. When I started DXing in the early 1970s, stations in the San José were spaced twenty-five kilohertz apart. That meant that every other station, such as Radio Sonora on 675 kHz and Radio Columbia on 725 kHz, was on a split frequency that fell between the normally assigned 10 kHz channels. I logged nine Tico stations on medium wave while DXing from Pennsylvania in 1972-1981 and only one of those, Radio Reloj on 700 kHz, was on an even channel. Those split channels were eliminated in the 1980s so logging Costa Rica on medium wave is no longer a slam-dunk.

I visited a lot of radio stations and took a lot of photos on my one long-ago trip to Costa Rica. I’m going to focus on just five shortwave broadcasters in this first look at Costa Rica. The others will be featured in two or three future columns.

In the 1970s the first Costa Rican station most shortwave DXers heard was Faro del Caribe, or Lighthouse of the Caribbean. This religious station used two kilowatts on 9645 and 6175 kHz and got out surprisingly well as long as there wasn’t a more powerful international broadcaster also using the same frequency. In the late 1970s they added 5055 kHz in the sixty-meter band.

When I visited in 1990 the antennas were located right next to the studio building. The site was outside the city of San José when the station was founded but gradually a residential area built up around it.

Engineer checking one of Faro Del Caribe’s shortwave transmitters.

Fortieth Anniversary pennant from 1988. When Faro del Caribe began broadcasting on February 23, 1948, it was the first Evangelical Protestant radio station in Central America.

For DXers, Radio Reloj was one of Costa Rica’s best known radio voices for several decades. The station was founded as Radio Cristal by Roger Barahona in 1945. The shortwave frequency of 6006 kHz was added in the early 1950s. In 1958 the station was renamed to Radio Reloj when the format changed to focus on news and community announcements with very frequent time checks. (Radio Reloj means Radio Clock.) Roger’s brothers Isaac and Francisco had joined the broadcasting company and Radio Reloj was assigned the callsign TIHB for Hermanos Barahona (Barahona Brothers). Continue reading →

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Remember the good olde days with a lovely cup of tea

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Hi to all of the SWLing community, Fastradioburst23 here with news about Imaginary Stations on the shortwaves this Sunday 20th August 2023. The first show will be beamed to Europe via the services of Shortwave Gold in Germany at 2000 utc on 6160 khz and will feature another transmission of WREN, this time it’s music of a Renaissance style, so turn back the hands of time to ye days of olde and tune in. You will get more out of the broadcast if you have a lute, recorder or a harpsichord handy.

Then later at 2200 hrs UTC on 9395 kHz via WRMI we bring you the debut of WTBR, your only official tea and biscuits radio show. There will an assortment of plain and fancy tunes and all the tea you can drink so make yourself (a tea) cosy and enjoy a nice relaxing time via the shortwaves. Even the Ionosphere will enjoy a little tea break to recharge its batteries.

For more information on the shows please email [email protected] and check out our old shows here. Here’s the trailer for the show.

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Guest Post: A review of the Chaoyuan LC90 Hybrid Shortwave/4G/Internet Radio

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Many thanks to SWLing Post contributor, Michael Ye (BD4AAQ), for the following guest post:

The LC90, a Great Radio Spanning Two Worlds

by Michael Ye (BD4AAQ)

It is an awkward era for radio receivers. Although technology becomes more and more advanced and increasingly sophisticated radios are made, there are fewer and fewer stations to listen to. But hardcore radio hobbyists, mostly hams and shortwave listeners, would not give up the hobby. They continue to look for and enjoy stations among noises in the airwaves. Although Internet radios have been around for a long time, I never thought seriously about them. Perhaps I was stubborn, but in my mind, radios were noises and noises were radios and it’s the stations among the noises that I enjoyed. Receivers without noises were hardly real radios.

Until I got my first full band radio with Internet features. The LC90 was a pleasant surprise, completely changing the way I look at radio receivers. The LC90, or “full band smart Internet radio”, is my first shortwave radio AND Internet radio in one. There may be other radios with Internet features, but I have heard of few receivers that integrate the traditional radio (shortwave in particular) and the Internet. The LC90 was launched in China in early 2023, and quickly became popular among hobbyists thanks to the unique combination. News has been confirmed that the overseas version of the LC90 will be launched later this year. It provides more options for users at a time when shortwave broadcasters continue to shut down transmitters and bid final farewell.

Chaoyuan Company

The manufacturer of the LC90 is Chaoyuan, an electronics company based in Shenzhen, China, known for mobile phone design and Hi-Fi equipment. In recent years they started to design and make radios. And they are serious about the business, too.

The LC90 full band smart Internet radio

The Radio at a Glance

The radio is of regular size. A computer mouse is placed in the picture above, so you have an idea of not only the radio’s looks but also its size. The exact dimensions are 200x122x40mm. Its weight is 640 grams. The radio has a built in 4G SIM card, with 3G prepaid data. You have to add credit to the card in time by scanning a QR code on the screen before the built-in SIM card expires. You can also use your own SIM card by inserting it to a slot at the bottom of the radio. And of course, you could use Wi-Fi at home.

Although the radio is a combination of the traditional radio and the Internet, it is very ingeniously designed and does not put off the user with too many bells and whistles – you could press the tuning button to change the shortwave band and the fine tuning button to change the band width. The tuning button also serves as an “enter” key. These are clever designs that effectively save extra buttons. I have not seen a similar design in other radios.

For those who do not read Chinese, the upper five buttons are, roughly, “Configure”, “Timer”, “Setup”, “History” and “Favorites”. The four buttons on the left: “Confirm”, “Stations”, “News” and “Menu”. The four buttons on the right: “Back”, “Sequence”, “Rewind” and “Fast Forward”. The button with a globe says “Internet”.

The radio has excellent audio quality, rich bass, with a well-balanced frequency response. It is powered by two 18650 rechargeable lithium batteries. The radio has no back stand.

Traditional Radio

All three modes (or bands) are available, FM, MW and SW, as shown in the three buttons on the upper right (to get LW just press MW again). The FM band covers 64-108MHz, which includes Japan’s FM band. During the FMDX season you could have stations from Japan and other countries to explore. The SW band covers 2300-26100KHz, continuous, almost the entire shortwave band, more than enough for broadcast listening. The antenna jack works for all three modes (or bands).

Excellent Shortwave Performance

As a shortwave listener of many years, I am most interested in the radio’s performance in shortwave reception. Well, it is indeed very good in terms of sensitivity, selectivity and audio quality, with no compromise although the radio has an Internet section which requires additional space and resources.

When you use the radio indoor, reception could be poor and you can insert an external antenna to the antenna jack. Unfortunately, I cannot connect my AOR LA400 loop antenna to it as the antenna jack is too close to the tuning knob and so there is not sufficient space for the plug (see picture). Generally, a 3.5mm plug with a wire should work well if you extend the wire outside.

The external antenna jack

If there is a disappointment, its shortwave reception does not decode SSB signals. If the user is not a ham radio hobbyist, SSB reception may not be really needed anyway and the buttons, circuits and space can be saved accordingly.

Fair FM Reception

FM reception is good, but there is no obvious improvement of reception when an external plug is inserted in the antenna jack.

Mediocre MW Work

Reception on the lower bands, e.g., the medium wave band, is always a challenge in cities. It is not surprising that medium wave performance of the LC90 is mediocre at best. I don’t do much MW DXing but nowadays for each MW frequency there is almost always an FM frequency. Let’s face it – we should perhaps forget about medium wave reception in cities where there is excessive low band EMI.

However, if you go outdoor with the radio, medium wave reception can still be a lot of fun. And, contrary to FM reception, an external antenna significantly improves its performance!

Internet Radio

Admit it or not, the best days of traditional radio are gone, and while we continue to have fun on the old time radio, we should not hesitate to embrace newer technologies such as the Internet. By launching the LC90 and combining the two, Chaoyuan has made a significant move.

The Internet radio is an integrator of many online stations on the Internet, and more. It is completely different from the traditional radio which receives radio signals transmitted on air. The Internet radio, which relies on the Internet, provides much better audio quality, no noise, customizable and replay-able.

If you want to kill time and look for signals from noises, turn to shortwave and enjoy DXing. If you feel like listening to solid content or enjoying noise-free music, the Internet radio is there for you. This Internet radio integrates major web stations in China and on that basis the user can further select and configure their own favorites. Among apps that are built-in is Ximalaya FM, the leading audio platform in China. Due to requirements of policies and regulations in China, the user does not have much discretion to include foreign stations in the radio. However, Chaoyuan has indicated that they are working in an effort to secure authorizations from Spotify, Alexa and Pandora which they hope could be incorporated in the overseas version of the LC90. The future overseas version is expected to give the user more discretion to include online stations of their own choice.

A closer look at the display of the Internet Radio

Two buttons, Ai1 and Ai2, are voice assistants. Activate and speak to them and the radio directly plays the content (Ai1) or displays their findings for you to choose from (Ai2).

Finally, this is a radio with the most accurate time. There is no need to set the time for it, as it is based on the Internet.

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An exotic bird flew into a supermarket…

The deep blue sea and trains this weekend on shortwave

TomL’s Guide to Audio Plugins For Radios: Part 2 – SDR Recording

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Many thanks to SWLing Post contributor, TomL, who shares the following guest post. Click here to check out all of the posts in this Audio Plugin series:

Audio Plugins For Radios, Part 2 – SDR Recording

by TomL

I started investigating using the old Kenwood transceiver to send audio to my laptop and process the receive audio using VST Host for a number of functions: Noise reduction, Equalization, reduce Sibilances and fading distortion, increase presence of vocals without sounding boxy, etc. It was a qualified success depending on what VST apps I used, in what order they were used, and what settings each of them were set to. In this episode of ongoing discovery, I will attempt to show how easy it is to OVER-process the shortwave broadcast audio plus comparisons to my regular Audacity post-recording treatment.

Audio Examples

I noticed for the first time that the SDR creates a somewhat compressed file which can be seen when comparing the Waveforms of SDR vs. VST Host output files. This means that the unprocessed SDR file will always appear to sound louder because of this compression. This loss of Dynamic Range makes it harder to do the comparison. Therefore, the Audacity-only examples below are reduced 3dB or 5dB to maintain apparent loudness.

Example 1: KBS Weekend Playlist – S6-S9 signal, somewhat severe fading and moderate polar flutter.

SDR Console 3.2 using my usual NR4 set to 2dB Reduction, 30% Smoothing, and 3dB Rescale plus a Blackman-Harris-7, 5.3 kHz filter.

AUDACITY file is using my usual Audacity noise reduction:

VST version 2: Used my first set of VST apps. Sounds harsh with hash-noise and overdriven:

VST version 3: Used way too much bass, too much grunge, attenuated highs, still overdriven:

VST version 4: Using a different order to the Denoiser apps, added in Modern Exciter app, cut back on some bass but still too much, and overly forward sounding midrange:

VST version 5: My current Baseline setup. Adjusted the Denoiser apps, less extreme bass & treble, adjusted the De-Esser app, set the midrange to be less forward with just a single setting:

To my ears, Audacity processing is nice but as discovered before, sounds compressed and does not reduce some of the other problems inherent in shortwave signal fading and loss of musicality. It sounds utilitarian. Also, the noise is a bit more gnarly.

Versions 2-5 go through iterations of listening to the exact same segment over and over (and over) and trying different VST apps and settings. I think my comments are mostly accurate next to each version. However, you may think differently and perhaps prefer the sound of one of the other versions?

Example 2: Encore Classical Music, WRMI (fading S9 signal) – Audacity vs. Version 5 VST settings. VST is quieter and sounds less harsh than the Audacity version. A generally more smooth sound.

Example 3: RCI in Russian, S7-S9 with moderate polar flutter – 7kHz filter in SDR Console but VST Host is using BritPre, an analog preamp using a 6 kHz low pass filter to try to reduce DSP filter “ringing”. It shows some interesting possibilities.

Example 4: RCI in Russian – Music from the same broadcast and VST Host setup in Example 3. The screeching flute is under more control and strings more defined in the VST version.

Conclusions

I like the results of the audio processing that eventually ended up with “version 5” (plus the possibilities at 7kHz, too). It is not Earth-shattering but is an incremental improvement in my opinion (there is always room for improvement). I can use it in a simple Workflow anytime I want to record something off of the SDR. Also, I had already been using Voicemeeter Pro, a software audio mixer. It is setup with different profiles to do SDR, Ham, FM Broadcast, and now, VST Host audio routing. This process took a long time but seems satisfactory to use as a Baseline setup, which then can be tweaked slightly depending on various types of audio coming from the SDR. These changes in VST Host can be stored as their own unique profiles for audio processing.

However, a word of warning! Messing with Windows audio Sound settings and mixer software is potentially a confusing process and one can easily end up with a spaghetti-pile of conflicting connections, no audio output, doubled echo output, distortion, way too loud, way too soft, etc. If you start this experimentation, make sure to write down your current Windows Sound settings, both the Playback and the Recording settings for each item listed.

Having an SDR radio + Voicemeeter + VST Host is a very flexible setup. I can now safely say that the only thing I need Audacity for is to Normalize the peak audio to the -1 dB broadcast standard volume, which is a HUGE time saver. The SDR Console IQ files can be scheduled and processed from there at a later time. Also, the use of Voicemeeter Pro allows me to switch when to use VST Host anytime I feel like it, and Voicemeeter Pro comes with its own (manually engaged) Recorder.

Part 3 of this series will discuss Technical details for my setup. Your setup may need different settings or you may find a better way than I did. This will take some dedicated time.

Happy Listening and 73’s,

TomL

Click here to follow all of the articles in TomL’s audio plugin series.

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