Category Archives: Music

Radio Waves: More RCI Services Come To An End, Pirate Radio Sound Tour, Shortwave Guitar Pedal, and Voyager 1 Detects Plasma “Hum”

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: 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 Marty, Richard Cuff, David Iurescia, and Doug Katz for the following tips:


RCI English section: goodbye (Radio Canada International)

Canada’s international broadcast service from the English language team of Radio Canada International has come to an end.

RCI, (originally the International Service, CBC-IS) was initially created towards the end of the Second World War. The purpose was to broadcast news and information from home via shortwave to Canadian military personnel fighting in Europe. It also began providing reliable news and information to recently liberated countries and to Germans still in the war.

That reliable news and information was considered of great value during the subsequent Cold War years, as several more languages were added to the service such as Russian, Ukrainian, Czech, Hungarian and Polish. Other languages sections included as Brazilian Portuguese and Japanese. With 14 language sections in 1990, and some 200 staff, the full English and French newsroom provided news of interest and importance for each language section specifically targeted to each of the various broadcast regions around the world.

Following a major budget cut of some 80 per cent in 2012, the shortwave and satellite service was terminated along with the majority of staff including the newsroom and some language sections. In recent years, only Chinese (Mandarin), Arabic, and Spanish remained along with English and French. RCI was transformed into a much smaller internet-based operation consisting of three people per language section.

In December 2020, the domestic public broadcaster CBC / Radio-Canada announced that the English and French sections of RCI would close for good in May. In their place curated stories from the domestic English and French public broadcaster will be provided.

A manager will now oversee the staff of eight who will adapt curated stories from the CBC and Radio-Canada into Mandarin, Arabic, and Spanish, along with Punjabi and Tagalog.

An effort was and is being made by the RCI Action Committee to preserve and even expand the service which has garnered great support from a former prime minister, former diplomats and many academics, but the end date has come. This is the last entry by the RCI English section.

From the English Section consisting of Lynn, Marc, and Levon, faithful and long-time popular replacement Terry Haig, and recently also Vincenzo Morello, and the many others over the all those years, we thank you for having shared our stories over these many years.[]


The Pirate Radio Capital: A sound tour with David Goren, radio producer and audio archivist (CRJ.org)

In 2018, David Goren, a radio producer and audio archivist, created the Brooklyn Pirate Radio Sound Map to collect the sounds of dozens of pirated broadcasts from across the borough. Pirate stations earn their name by hitching a ride on already licensed radio frequencies that typically cost commercial stations millions of dollars to acquire and set up. Nowhere in the country are there more pirate radio stations than in New York, where they provide a vital service to immigrant populations.

Goren estimates that New York has about a hundred pirate stations, transmitting from rooftops and attics to listeners seeking news from around the city and back home, as well as

entertainment and religious programming. The broadcasts bypass socioeconomic barriers and provide a means to seize control of the flow of information. But they are now at risk of extinction: Before Donald Trump left the White House, he signed the Pirate Act, which increased the authority of the Federal Communications Commission to fight pirate operations through mandatory sweeps in cities with high concentrations of pirate radio use. Pirate stations today face fines of up to two million dollars. “The people running these stations, they don’t have two million dollars,” Goren said. Broadcasters that don’t make it onto his sound map could be lost forever.

Click here to read the full story and listen to the audio tour with David Goren.


Shortwave effects pedal (Recovery Effects)

Inspired by espionage devices used during World War II and the Cold War, Shortwave transforms audio into clandestine operations of the past; Russian number stations, mysterious sounds transmitted by radio, and eerie sounds stored on early portable recorders.

Choose between 2 types of noise and interference, and control it with the Exposure parameter. Velocity and Focus control the amount of pitch stabilization. Shortwave will add an interesting emotional response and atmosphere to dry, simple sounds, or destroy a signal like no other fuzz pedal can.

Hand-made in Seattle, WA. Shortwave operates on a standard “Boss” style 9vdc power supply (not included), but can also run at 18vdc for additional headroom. True bypass switching. Included a limited-lifetime warranty.

Enclosure size: 4.77″ x 2.6″ x 1.39″


In the emptiness of space, Voyager 1 detects plasma ‘hum’ (Cornell.edu)

Voyager 1 – one of two sibling NASA spacecraft launched 44 years ago and now the most distant human-made object in space – still works and zooms toward infinity.

As the craft toils, it has long since zipped past the edge of the solar system through the heliopause – the solar system’s border with interstellar space – into the interstellar medium. Now, its instruments have detected the constant drone of interstellar gas (plasma waves), according to Cornell-led research published May 10 in Nature Astronomy.

Examining data slowly sent back from more than 14 billion miles away, Stella Koch Ocker, a Cornell doctoral student in astronomy, has uncovered the emission. “It’s very faint and monotone, because it is in a narrow frequency bandwidth,” Ocker said. “We’re detecting the faint, persistent hum of interstellar gas.”

This work allows scientists to understand how the interstellar medium interacts with the solar wind, Ocker said, and how the protective bubble of the solar system’s heliosphere is shaped and modified by the interstellar environment.

Launched in September 1977, the Voyager 1 spacecraft flew by Jupiter in 1979 and then Saturn in late 1980. Travelling at about 38,000 mph, Voyager 1 crossed the heliopause in August 2012.

After entering interstellar space, the spacecraft’s Plasma Wave System detected perturbations in the gas. But, in between those eruptions – caused by our own roiling sun – researchers have uncovered a steady, persistent signature produced by the tenuous near-vacuum of space.

“The interstellar medium is like a quiet or gentle rain,” said senior author James Cordes, the George Feldstein Professor of Astronomy (A&S). “In the case of a solar outburst, it’s like detecting a lightning burst in a thunderstorm and then it’s back to a gentle rain.”

Ocker believes there is more low-level activity in the interstellar gas than scientists had previously thought, which allows researchers to track the spatial distribution of plasma – that is, when it’s not being perturbed by solar flares.[]


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KSOL via WRMI on Sunday, May 16, 2021

(Source: Pete Madtone)

From the great WRMI we have another transmission from KSOL – The alternative dimension/universe edition this Sunday/Monday 16th/17th May on 9395 kHz. When the clock strikes 2300 UTC or Midnight UK time expect some chilled tunes including a mini-mix from One Deck Pete at 40 minutes in.

As soon as the transmission is over it’ll be up on the KMTS Mixcloud here. And here’s KSOL from last week whilst we’re there. #shortwavesnotdead #KMTS #KTMS #KDUB #KMRT

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TomL’s guide to making and optimizing shortwave radio SDR music recordings

An example of an AirSpy SDR# software screen.

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


Recording Music on Shortwave

by TomL

I recently became curious about the seasonal music updates posted by Alan Roe.  It is a nicely detailed list of musical offerings to be heard.  Kudos to Alan who has spent the time and effort to make it much easier to see at a glance what might be on the airwaves in an easy to read tabular format.  I do not know of any other listing specifically for shortwave music in any publication or web site.  I especially like the way it lists everything in UTC time since I might want to look for certain time slots to record.  For some listings, I would need to go outdoors away from noise to listen to certain broadcasts.  Current web page is here:  https://swling.com/blog/resources/alan-roes-guide-to-music-on-shortwave/ .

As a side note, I have also found a lot of music embedded in the middle of broadcasts that are unannounced, unattributed, and not part of a regular feature program.  That can be a treasure trove of local music you might not be able to find anywhere on the internet.  It can be worth recording a spectrum of frequencies using the capabilities of the SDR and then quickly combing through the broadcasts at two-minute intervals (most songs are three minutes or longer).  In maybe ten minutes, I will have at least identified all of the listenable music that may or may not be worth saving to a separate file.

Whether at home or outdoors, I have wanted to try to record shortwave broadcasts of music using my AirSpy HF+ but never getting around to it until now.  There is a certain learning curve to dealing with music compared to just a news summary or editorial.  I found myself wishing I could improve the fidelity of what I was hearing.  From static crashes, bad power line noise, fading signals, and adjacent channel interference, it can be quite difficult to get the full appreciation from the musical impact.

I am starting to monitor the stronger shortwave stations like WRMI, Radio Romania International, Radio Nacional do Amazonia, etc.  These type of stations can be received in a strong enough manner to get good quality recordings (at least according to shortwave listening experience).  I am also finding that I appreciate much more than before the effort that these broadcasters put into creating content/commentary to go along with the music and little pieces of background info about the music or the artist.  I have also noticed how exact some broadcasters are in timing the music into the limited time slots.  For instance, Radio Romania International tries to offer one Contemporary piece of music exactly at 14 minutes, Traditional music exactly at 30 minutes, and a Folk tune exactly at 52 minutes into the program (whether in English, French, or Spanish), with nice fade-outs if the music goes too long.

One thing I ran into was to bother checking my hearing range.  If someone has impaired hearing, it does not make much sense to create files that have a lot of sound out of one’s hearing range.  I found this YouTube video (among a bunch of others) and listened to the frequency sweep using my Beyerdynamic DT-990 Pro headphones (audiophile/studio type headphones).   My hearing is approximately from 29 Hz through 14400 Hz.  Of course, the extremes fall off drastically, and as with most people, my hearing is most sensitive in the 2000 through 6000 Hz range.

Recording Workflow

Let’s assume that you already know how to record IQ files using your SDR software and can play them back (In the example below, I recorded the whole 49 meter band outputting a series of 1GB WAV files).  Then, when playing back to record to individual files, I have to choose the filters and noise reduction I want.  This gets subjective.  If I do not want to keep huge numbers of Terabytes of WAV files over time, I will want to record to individual WAV files and then delete the much larger spectrum recording.  You might tell me to just record to MP3 or WMA files because there is that option in the SDR software.  We will get into that as we go along.  For the time being,  I do not want to keep buying Terabytes of hard drives to hold onto the original spectrum recordings.

After lots of trial and error, I came up with this workflow:

  1. Record the meter band spectrum of interest using the SDR software.
  2. Record individual snippets of each broadcast in that spectrum to new individual WAV files.  This includes not lopping-off any announcer notes about the music I want to retain.  I also have to choose the bandwidth filter and any noise reduction options in the software.  Because I am not keeping Terabytes of info, this is a permanent decision.
  3. Take an individual recording and apply more processing to it.
  4. Convert the processed  recording to any number of final output formats for further consumption and/or sharing.
  5. Repeat steps 3 & 4 to take care of all the individual WAV files.

Step 4 allows me to create whatever file format I might need it to be: WAV, MP3, WMA, or even use it as background sound to a video if I so choose.  There are also different ways to create some of these files with different quality settings depending on what is needed.  I have chosen to listen to the individual WAV files for personal consumption but there may come a time to create high quality MP3 files and transfer those to a portable player I can take anywhere (or share with anyone).

The example below is a snippet from the latest Radio Northern Europe International broadcast on WRMI.  WRMI has some decent equipment and I like how clean and wide is the bandwidth of many of the music programs.  This is captured on the AirSpy HF+ using SDR Console V.3 with a user-defined 12kHz filter (11kHz also seemed somewhat similar sounding).

If you click on the ellipses, you can Copy an existing filter, type in a new title and change the bandwidth.  I also played around with the different Windowing types and found that I like the Blackman-Harris (7) type best for music and the Hann type for smooth speech rendering (the Kaiser-Bessel types can also have more “punch” for voice recordings).  Click OK TWICE to save the changes.

I also use Slow AGC and the SAM (Sync with both sidebands) to reduce the chance of distortion as the signal fades.  I found that trying to use only one sideband while in Sync mode would make the reception open to loss of Sync with the musical notes warbling and varying all over the place!

Noise Reduction

The SDR Console software has a number of noise reduction choices.   I tried NR1 through 4 and found the smoothest response to music to be NR1 with no more than 3 dB reduction.  More than this seemed to muffle the musical notes, especially acoustic instruments and higher pitched voices. Part of the problem has to do with trying to preserve the crispness of the articulation of the sound and combating shortwave noise at the same time.  At this time, I have chosen NOT to use any NR mode.  More about noise reduction below.

Generic MP3 sounds really bland to my ears, so creating higher quality files will be important to me.  I have been using Audacity which can apply processing and special effects to WAV files and export to any number of file formats.  WAV files are a wonderful thing.  It is a “lossless” file format which means that every single “bit” of computer input is captured and preserved in the file depending on the resolution of the recording device.  This allows one to create any number of those “lossy” output formats or even another WAV file with special effects added.  You can get it here:

https://www.audacityteam.org

One special effect is listed as “Noise Reduction”.  I literally stumbled upon it while reading something else about Audacity (manual link).  Here is how I use it for a shortwave broadcast.  Open the original spectrum recording (in this example the 49m band).  Tune about 25kHz away from the broadcast that was just recorded.  Remember, my hearing extends at least to 14.4k plus there is still the pesky issue of sideband splatter of bandwidth filters.  The old time ceramic and mechanical filters use to spec something called “skirt selectivity” -60db or more down from the center frequency.  This is still an issue with DSP filters even though they SAY they are measured down to -140dB; I can still hear a raspy sideband splatter from strong stations!

Find the same time frame that you recorded the broadcast and make sure it is the same bandwidth filter, AGC, and any noise reduction used.  Now record one minute of empty noise to a WAV file.  Fortunately on 5850 kHz, WRMI has no adjacent interference.

Now in Audacity, open the noise sample and listen for a 5 to 10 second space to copy that is relatively uniform in noise.  We don’t want much beyond that and we don’t really want noise spikes.  The object is to reduce background noise. In this case, I chose Start 39 seconds and End 44 seconds.  Choose Edit – Copy (or CTRL-C).

Choose File Open and find the broadcast WAV file in question.  Now click on the end-of-file arrow or manually type in the Audio Position (in this example 1 minute 15 seconds).  Now Paste (or CTRL-V) the 5 seconds of noise to the end of the broadcast file.  Now, while the pasted noise is still highlighted, go immediately to Effect – Noise Reduction and choose the button Get Noise Profile.  It will blink quickly to read the highlighted 5 seconds of noise and disappear.

Now select all with CTRL-A and the whole file is selected.  Go immediately to Effect – Noise Reduction and choose the parameters in “Step 2”.  Through some trial and error, I found 3db reduction has a noticeable effect without compromising the music.  I have used up to 5 db for some music recorded with narrower bandwidths.  Higher levels of noise reduction seemed to create an artificial flatness that was disturbing to me.  I also use a Sensitivity of 0.50 and Frequency smoothing of 0.  You can choose the Preview button while the Residue circle is checked to actually hear the noise being eliminated.  Press OK in order to process the noise reduction.  You should now see the waveform change slightly as the noise is filtered.  In a nutshell, I find this to be a better noise reduction than using 3db of NR1 in the SDR Console software.  Don’t forget to snip off those 5 seconds of noise before saving the file.

Pseudo Stereo

The SDR Console software has an Option for Pseudo Stereo (for playback only) and it can be useful for Amateur Radio receiving, especially in noisy band conditions when one is straining to hear the other person’s call sign and location.  There is a way in Audacity to add a fake kind of stereo effect to mono audio files.  I found a useful YouTube video that explained it very clearly.

I  do everything listed there except for the Reverb effect.  I find that too fake for my tastes.

I found the added 10ms of Delay on the right channel to be a little too much, so I use 9ms.

My High Pass filter settings are 80 Hz and 24dB/octave.  This is based partly on my hearing preferences as well as established industry standards.  There was a lot of science and audio engineering that went into creating the THX home theater crossover standard.  There is also science that says that anything below 200 Hz is omnidirectional.  The suggested 48dB/octave is too steep in my opinion.

My Low Pass filter settings are more squishy.  The YouTube video suggests 8000 Hz and 6dB/octave.  I feel that is too gentle a rolloff into the upper midrange.  I use 9000 Hz at 12dB/octave for very strong, high quality shortwave broadcasters like WRMI. For more constrained quality broadcasts, like due to limited bandwidth (Cuban broadcasters) or adjacent channel interference, I will decrease down to 8000 or 7000 Hz but still use a 12dB/octave rolloff.  This is subjective but it also means I am making a conscious decision to add that processing to the recording for future listening.

MP3 Quality

Typical MP3 files are a Constant Bit Rate of 128k.  Some interviews and voice-only podcasts are only 64k.  This is adequate but for recording detail in the music I prefer higher quality settings.  Frankly, with these days of 4G cell phone service and Unlimited Data minutes on cell phone plans, there is NO good reason to limit MP3 files to just adequate quality levels.  The typical MP3 file sounds limited in frequency range (muffled sounding) to me and very lacking in dynamic range (narrow amplitude).  This would include limits on stereo files which are about twice the file size of mono files.

I have tried creating WMA files and I actually like the quality a little better than high quality MP3 files.  The WMA files seem slightly more “airy” and defined to my ears.  But it is a proprietary format from Microsoft and not all web sites or devices will easily play them.  They are also a fixed standard and one cannot easily change the quality settings if forced to use a lower quality rendering.

There are many web sites talking about MP3 files, but I found this blog post helpful in summarizing in one paragraph the higher quality settings for a nice MP3 recording using VBR-ABR mode.

https://technical-tips.com/blog/software/mp3-encoding-right–1334

One Minute Samples

So finally for my examples.  Since most web sites still prefer MP3 files, I have created these using that  blog post’s suggestions.  Typically this is Min bitrate=32, Max bitrate=224, VBR quality=9, and Quality=High (Q=2).  Let’s see if you can hear the differences.  It would be much easier to hear if we were listening to WAV files, but those are way too big to post on this web site!  The software I used is Xmedia Recode and I find it easy to use.

https://www.majorgeeks.com/files/details/xmedia_recode.html


Example 1: No noise reduction in SDR Console, no further processing


Example 2: 3dB of NR1 in SDR Console, no further processing


Example 3: No noise reduction in SDR Console, Audacity Noise Reduction of 3dB


Example 4: No noise reduction in SDR Console, Audacity Noise Reduction applied 3 times (3db,0.33+2db,0.50+1db,0.80)


Example 5: No noise reduction in SDR Console, Audacity Noise Reduction applied 3 times (3db,0.33+2db,0.50+1db,0.80), Pseudo Stereo added


I would love to hear comments since I am new to recording music on shortwave and any further tips/tricks would be fun to learn.  Enjoy the music!

TomL

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Alan Roe’s A21 season guide to music on shortwave (version 2 update)

Many thanks to SWLing Post contributor, Alan Roe, who shares his latest A21 season guide to music on shortwave.

Click here to download as a PDF.

Note that we’ve created a permanent page for Alan Roe’s guides!

This page will always have the latest version of Alan’s guide available for download.

Spread the radio love

Alan Roe’s A21 season guide to music on shortwave

Many thanks to SWLing Post contributor, Alan Roe, who shares his latest A21 season guide to music on shortwave.

Click here to download as a PDF.

Note that we’ve created a permanent page for Alan Roe’s guides!

This page will always have the latest version of Alan’s guide.

Spread the radio love