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Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art from two recent reports and a radiofax.
Good morning, Thomas.
My radio activity on August 10, 2023.
Attached are two illustrated listening reports about Typhoon Khanun: one from Okinawa Fishery radio station and the other from KBS World Radio.
Also attached a typhoon warning issued yesterday by South Korean meteorology agency via radiofax at 05h00 UTC and received in Porto Alegre. Signal wasn’t good, therefore image arrived with poor quality. Even though, it’s possible to notice the map of Korea and the path of Typhoon Lan, now a tropical storm.
Thank you so much for documenting these broadcasts, Carlos, and sharing them with us in the SWLing Post community!
Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art of a recent Okinawa Fishery Radio Station Typhoon Alert.
Carlos notes:
Okinawa fishing radio station issued an alert today for typhoon Khanun, and the transmission was listened in Porto Alegre, Brazil.
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:
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.
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!
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.
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!
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….