Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art of a recent Voice of Turkey transmission.
Carlos notes:
Part of news bulletin from Voice of Turkey radio, listened in Porto Alegre, Brazil (9870 kHz). Scores killed in police operations in Brazil.
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:
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.
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.
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.
Many thanks to SWLing Post and SRAA contributor, Dan Greenall, who shares the following off-air shortwave radio recording and writes:
In all of the recordings of Radio Botswana’s famous barnyard interval signal I can find, the barnyard sounds are accompanied by the sound of cowbells. There is usually a rooster crowing and cows mooing too.
Today, while revisiting some raw tape from an old cassette dated 1973, I came across a short [off-air] recording of some similar barnyard sounds, chickens clucking and cows mooing. No sign of the cow bells here, but perhaps they started up farther into the interval signal?
If this recording is from Radio Botswana, perhaps they were only using the animal sounds in 1973? Maybe someone out there can help with this? Sorry but I have no other info. Many thanks!
Dan Greenall
London, Ontario Canada
Thanks for sharing this, Dan.
If you can shed some light on this recording and if Radio Botswana’s interval signal has changed over the years, please comment with details! Thank you!
Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!
Many thanks to SWLing Post contributors Ron Chester, Benn Kobb, Chuck Rippel, Pietschman, Dennis Dura, and Dave Zantow for the following tips:
The FCC seeks comments on a proposal to use HF spectrum for financial data
The FCC is taking public comment on a proposal to revise the rules governing the frequencies above 2 MHz and below 25 MHz.
The Shortwave Modernization Coalition thinks the 2-25 MHz band is underused and wants to use it for the long-distance transmission of time-sensitive data from fixed stations. The users would be companies working with certain kinds of financial transactions; the proposal would prohibit voice transmission and mobile operations.
The firms in the coalition are “market makers and liquidity providers” for exchange-traded financial instruments.
This high-frequency trading industry has in fact been using shortwave links for several years to send trading data between U.S. and foreign exchanges, but it has done so under experimental authorizations. [Continue reading…]
Many thanks to Bill Pietschman who notes that the book “QTC: I Have a Message for You” has now been published on Archive.org for all to read and download free of charge. Bill writes:
I knew Ray Redwood, and besides being a Professional radio operator, he was indeed a Ham’s Ham. You will find here not just the story of radio, but a detailed analysis of the Titanic, from a radioman’s point of view. Part documentary, part autobiography, and part technical, it’s a great read. I’m so glad that his work has been preserved here. Future radio historians will, I am certain, find it to be a valuable record of the Ship Radio Officers Era, and Ray’s insights at the dawning of the Global Maritime Distress and Safety System as we have today which utilizes satellite technology.
Click here to check out QTC: I Have a Message for You on Archive.org.
There was a time, some 50 years ago when cell phones didn’t exist and computers were only owned by large corporations, that people learned of the world around them by listening to shortwave radio. This is a journey back to that time to hear the sounds and see the correspondence from shortwave stations from all over the world. Sit back, listen and enjoy!
Steve Brightman (KI5ENW) from SDRplay demonstrates the new updates to SDRconnect to Ham Radio Outlet’s Julian Frost (N3JF).
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Many thanks to SWLing Post contributor, Paul Walker, who shares the following video of his open-air DX shack in McGrath, Alaska. Paul notes:
I got my iRig working and recorded audio of Rádio Nacional da Amazônia on 11780 kHz directly from the radio into my phone and it sounds really good with such a strong signal here in ALASKA. Take a listen….
Click here to view on YouTube.
Thanks for sharing this, Paul! That does sound amazing–like a local station!
You, sir, are a true DXer! Anyone who regularly braves frigid temps to chase far-flung DX is made of some incredibly tough stuff!
Thanks for sharing, Paul!
Many thanks to SWLing Post contributor, Pete Jernakoff, who writes:
Last Saturday evening, I was cruising through the SW bands and came across music and talk on 2640 kHz, a rather odd (I would think) frequency on which to find such a broadcast format.
The music was of the soft pop variety (for example “Vou de Taxi” by Angelica; “A Time For Us – Love Theme from Romeo and Juliet” by Jack Jones; “A Lua E Eu” by Cassiano), and it sounded to my ears that the on-air talent (male) was speaking (between songs) either in Portuguese or in a Brazilian dialect of said language.
I have attached an audio clip of this broadcast [see below] which begins at 0158 UTC (on 26-March-2023). The recording is a little over 13-minutes long and ends when the signal abruptly leaves the air.
Note that there is a seeming mention in the recording of the words ‘Brazil’ and ‘Brasilia’ at the 4:40 and 5:03 time points, respectively. I have no clue where this signal originated, and I’m hoping that you or one of your many readers might be able to help ID this one. As far as I’m aware, there is no station that broadcasts on this frequency at least with this kind of programming. The signal seemed too strong to be a harmonic of a station broadcasting on, say, 1320 kHz. Perhaps a pirate? A mystery to me…
Thanks for sharing this recording, Pete!
If you can help Pete ID this mystery recording, please comment!
A Cuenca Artisan Market
Many thanks to SWLing Post contributor, Don Moore–noted author, traveler, and DXer–for the latest installment of his Photo Album guest post series:
by Don Moore
In the song Por Eso Te Quiero Cuenca (That’s Why I Love You Cuenca) the singer recites a litany of the many reasons to love this city. What do I love about Cuenca? Well, unlike the song, I won’t include well-roasted guinea pig.
The elevation of 2560 meters (8,400 feet) gives Cuenca a comfortable spring-like climate year-round. Daily highs are usually around 20C/70F. Nights are chilly but not cold. Most days have at least several hours of sun, even during the rainy season (as it is now). There are numerous green parks and plazas including long tree-lined walking paths along the two main rivers that run through the city. The drinking water, which comes from high up in the mountains, is the best in South America. Yes, you can drink it right from the tap.
A walking/bike path runs along the Yanuncay River for over six kilometers through the south side of Cuenca. A similar path runs along the larger Tomebamba River in the center of town.
The people of Cuenca are among the friendliest I’ve found anywhere. It’s a well-run, educated city with lots of civic pride. The metro area population is only about a half-million so it’s small enough to easily get anywhere but large enough to have the benefits of a city. Cuenca has several good universities and theaters and the symphony orchestra gives free concerts most Friday evenings. It’s a pleasure to simply stroll through the beautiful architecture in the old centro neighborhood.
One of many beautifully restored buildings in Cuenca’s old centro.
Getting around Cuenca is easy. A ride on the excellent bus system costs just thirty cents and taxi rides usually run under two dollars. And, unlike the much larger cities of Quito and Guayaquil, Cuenca has a mass transit system. In 2013 city leaders voted to put in a light rail line. Doing so required digging up two of the main streets through the old downtown but rather than just dig up two streets they decided to dig up the entire old downtown … to replace the aging water and sewer systems, move all electric lines and cables underground, and install high-speed fiber optic Internet. (Fiber optic Internet was also run above ground in the newer neighborhoods outside the centro.) The result is one of the few places in Latin America where one can enjoy beautifully restored architecture and colonial churches without the views being marred by powerlines. And the Internet here is better than most places I’ve stayed at in the United States.
Those are just a handful of the reasons that I love Cuenca.
Radio broadcasting in Ecuador started in 1925 with Radio El Prado in Riobamba, a small city in the center of the country. Other stations soon started up in Guayaquil and Quito, including HCJB in 1931. Broadcasting came to Cuenca in 1934 when a group of friends purchased a homemade ten-watt transmitter from an engineer in Guayaquil and put it on the air as La Voz de Tomebamba. The name came from the main river flowing through Cuenca. At the time there were only four receivers in the city so the audience was rather sparse. La Voz de Tomebamba initially broadcast for only one or two hours a night and most of the musical selections were done live as there weren’t many 78 RPM records in town. Years later one early listener reminisced, “It was sixty percent noise. Only radio fanatics could be entertained by listening to such a thing.”
Old studio equipment from La Voz de Tomebamba
Gradually, the owners added new equipment and expanded the daily schedule. A fifty-watt transmitter was added in 1938 and by 1947 the power had been increased to two hundred watts. The first frequency listing that I’ve found for La Voz de Tomebamba was for 4200 kHz in a 1944 FBIS newsletter. The 1947 WRTH listed it as on the air from 0000 to 0430 GMT on 4200 kHz. And that was the station’s only frequency. Until the 1960s it was very common for radio stations in Ecuador to only broadcast on shortwave and not on medium wave. For example, the 1957 WRTH lists eighty Ecuadorian stations on shortwave (not counting HCJB) but only fifty-nine on medium wave.
Sometime in the early 1960s La Voz de Tomebamba made the switch to medium wave and left shortwave. Their 4200 kHz frequency is not listed in the 1965 WRTH, nor are they listed in any later ones. (I would be interested to hear from anyone who remembers listening to them on shortwave.) The changes may have had to do with financial problems the station was having. It closed in 1967 and remained off the air until returning under new ownership four years later. Today La Voz de Tomebamba is one of the most popular radio stations in town and has an excellent news department. Their sister station, Super Rock FM 94.9, is very popular with younger listeners.
La Voz de Tomebamba today.
The second station in Cuenca was Radio Cuenca, which began broadcasting in October 1945 on 2830 kHz with two-hundred watts. It was included in a 1953 list of stations logged by the Universal Radio DX Club of Indiana. To the local audience, Radio Cuenca was best known for its many live music broadcasts. Continue reading