Shortwave gems part 1

Friday, September 23, 2016
In this post I include some of the more interesting things I have recently heard on shortwave using both my outdoor and indoor recording setups. Some of these recordings were made using standalone shortwave radios while the others were extracted from my SDR spectrum captures.

Very interesting vocal style heard on Ethiopia's Radio Fana. Recorded outdoors.

A British Airways flight bound for Antalya communicating with a ground control station over Stockholm Radio about a disturbance onboard. Recorded outdoors.

More of the traditional Korean clarinet music that is rather unusual for North Korea's shortwave service. Recorded outdoors.

Tajikistan's shortwave service, usually a difficult catch in Western Europe. Recorded outdoors.

Some incredible vocal dexterity from the Moldovan singer, Laura Lavric, heard on Romania's longwave service, Antena Satelor, recorded indoors.

Raï and Hip-Hop fusion on Algeria's Jil FM, received on mediumwave indoors.

Continue reading →

Radio Australia shortwave outage

Tuesday, August 16, 2016

Over the past few days, I and many other shortwave listeners have noted that Radio Australia can no longer be heard on the air. Many of those who contacted the broadcaster received a cut-and-paste statement in response, saying that the outage is a result of technical maintenance. The wording is somewhat suspicious, however:
We are currently working with our transmission provider on a number of shut downs over the past week and again over the next week to investigate a range of technical and commercial issues for the service.
(emphasis mine). This reminded me of a comment from one of my blog readers, left in response to our endangered shortwave stations initiative:
rubbersoul1991 on 3 May 2016 at 02:46 
Thanks for the post. The Australian Government is about to hand down its 2016/17 budget tonight and has foreshadowed another round of cuts to the ABC. The new head of the ABC is an ex Google executive [...] so a nuanced response may not be forthcoming. These are dark days for Radio Australia and it may not survive another year.
The budget was passed shortly after the comment was left, but could Radio Australia be quietly testing the waters with ceasing shortwave broadcasts in advance of the next round of possible cuts?

The usual arguments about the economics of running a high-powered shortwave radio service are well known and have been discussed many times over. And time and again, what is missing from these discussions is the humanitarian aspect: depriving people in the less advantaged territories of the ability to receive global broadcasts at no cost results in a less equal world. A good friend of mine from India who went on to become a highly successful academic in the USA attributed his career path to regularly listening to the BBC World Service and Voice of America on shortwave while growing up in a poor neighbourhood. True, India is now much better connected than it was back then, but in how many other regions will shutting down shortwave radio result in lost opportunities for the people there to connect with the rest of the world? We wouldn’t dream of cutting Internet access in poor neighbourhoods in our own countries; shutting down all libraries in less privileged parts of our cities would result in an outcry. I find it hard to believe that this point is lost on the people charged with making such decisions and one can only hope that this is indeed a temporary outage.

Update (17/08/16) from Radio Australia's reception advice:

Update (19/08/16):

Continue reading →

A few catches from the indoor spectrum grabs

Saturday, June 18, 2016
I am enjoying using my indoor spectrum capture set-up for recording endangered shortwave stations. The set-up relies on my earlier work on mitigating urban radio interference, caused by being in a busy apartment building in London:
I thought I'd share a few of the catches I have made so far. First up, some good music. Here's an atmospheric set from the Voice of Greece on April 21st, 2016 at 2340 UTC:

A beautiful set of qawwalis and ragas from All India Radio Urdu service, recorded on May 23rd, 2016 at 0055 UTC. I especially like the song at 5 minutes 30 seconds into the recording:

I have also been fortunate to catch some more distant transmissions, such as Radio Thailand on 13/06/2016 at 1900 UTC:

A nice bonus that I didn't expect to show up in the spectrum recordings was the Voice of Turkey's English language broadcast on 04/06/2016 at 0300 UTC:

Finally, propagation from Cuba hasn't been great lately and I certainly have much clearer recordings of it from indoors than the one below, but the SDR# software did a fine job of pulling it out from the noise:

Overall, this has been a fun little project and given that I can make these recordings regularly (unlike the trips to my local park), there is a steady stream of gems to be extracted from the radio static and explored.
Continue reading →

Morse code transmission over the Voice of Turkey's signal

Wednesday, June 15, 2016
I have been regularly recording the small spectrum window containing the endangered stations I mentioned in one of my previous posts. Three days ago I noticed something strange: a morse code transmission superimposed onto the Voice of Turkey's signal on 9460 kHz (video below):

Using SDR# I extracted the coded signal while suppressing the rest of the audio (recording embedded in the player below):

My Morse knowledge is patchy to say the least, so I decoded it using Fldigi. At the start of the recording, the sequence "8T1" is repeated a dozen of times. I Googled around and found another YouTube video of a Morse code transmission from a numbers station, reportedly codenamed M01, which also had multiple repetitions of "8T1".

Numbers stations are still sending messages from many different corners of the world. However, if I indeed captured an M01 transmission in this instance, what makes it unusual is that it was embedded inside a signal from a broadcast station and that it was strong enough to be heard clearly. I'll watch out for further occurrences of M01 on the airwaves.

Update: I received the following pointer from @priyom_org:
While the station supposedly operates daily, it's the first time I heard it over the Voice of Turkey's broadcast at that time of day. Continue reading →

Shortwave playlist part 5

Thursday, May 19, 2016
The shortwave music expedition continues with the fifth instalment of the playlist.

1. Palyrria - Ikariotikos(Dry Mix)
Voice of Greece, May 2016

Born out of the need for experimentation PALYRRIA is a band that has devised and perfected its own, unique musical style. Created in 1999 Palyrria indulged in a mixture of western electronica and traditional music from around the Mediterranean. They call it world-electro and indeed this music is neither electronic nor ethnic. PALYRRIA has always been fascinated by traditional music and some of the bands members have worked with renowned traditional musicians, but living in Greece one realizes that traditional music goes way beyond the last millennium, back in times when people chose to express themselves in much more ecstatic and pagan ways. Ancient ceremonies around the Mediterranean have always been filled with music and musical expression. In a way, it wouldn't be too far from the truth if one was to draw a parallel between those events and the rave parties the world witnessed in the beginning of the nineties. The similarities are striking and have been the source of inspiration for the dynamic musical context of PALYRRIA. Aeolian scales, pentatonic music, instruments that come out of the depths of history, are presented alongside pumping bass lines, techno grooves, vocoders, clicks and cuts, in an attempt to create music that transcends the centuries and is both ancient and futuristic at the same time. Let the strangeness ware off and enjoy music that comes straight from the source. (Discogs)

2. Berbang - Ezim Kurdistan
Denge Kurdistane, September 2015

3. Adnane Chaouachi - Ya Ward Mfatah
RTV Tunisia, December 2013

Adnène Chaouachi (عدنان الشواشي), born in Beja, is a musician, composer and Tunisian singer. (Wikipedia)

4. Mohammed Abdu - يالله إني في رجاك
Medi 1, January 2016

Mohammed Abdu Othman Al-Aseeri, (Arabic: محمد عبده عثمان العسيري ‎) (born June 12, 1949) is well-known Saudi singer all across the Middle East. He had been described as "The Artist of Arabs". (Wikipedia)

5. Karan Khan - Inkar Kawi Na Sam Kawi Iqrar Sta Baanrha
Radio Azadi, December 2015

Karan Khan is a renowned Pashto singer, broadcaster, music developer and PhD in Pashto. (Facebook)
Continue reading →

Endangered Shortwave Stations

Sunday, April 24, 2016
Last week, when talking to my friend and fellow shortwave archivist Thomas Witherspoon about using software-defined radios to capture and preserve parts of the shortwave spectrum, he and I suddenly stumbled upon an idea: creating a curated list of endangered shortwave radio stations. We could use such a list, we thought, to focus our own efforts and those of the community on archiving the transmissions that were the most likely to disappear in the near future.

Shortwave Radio Audio Archive endangered stations page -
Thomas went ahead and quickly put together a draft version of this list, available here, and I added a few items to it. However, it's difficult to get up-to-date information on the stations' closure plans, as the organisations that sponsor shortwave broadcasters usually don't give much notice when deciding on funding cuts, so we will have to figure out a way of keeping it current (perhaps we can also use this list as a point of contact for whistleblowers?).

The list has already helped me to prioritise my shortwave recording activities. For the past four days I have been using my indoor SDR set-up (FunCube Dongle Pro+, MacBook Pro running Windows on VMWare and SDR#, plus the entire anti-interference set-up, described in one of my earlier posts) to record a small window of the shortwave spectrum that contains two critically endangered stations: the Voice of Greece (9420 kHz) and All India Radio (9445 kHz). These are late evening transmissions that I can't capture from the park for practical reasons. Some effort was required to tune the equipment for stable indoor reception:
The effort has already paid off, however: having recorded close to 14 hours of the Voice of Greece, I noticed that the station went off the air again last night. VOG is known for its irregular broadcasting hours, so not much surprise there, yet it's hard to predict when it resumes its programming. Hopefully, fellow enthusiasts will get in on the act and record the broadcasters that are teetering on the brink of shutdown. What stations do you think are critically endangered? Please leave your thoughts in the comments section!

Continue reading →

Denoising old shortwave recordings with SDR#

Wednesday, April 20, 2016
Readers of this blog may already know that I live in a densely built-up part of London, which is a very harsh environment for listening to shortwave radio indoors. I have come up with some RFI mitigation strategies, but these work best when the underlying radio signals are still relatively strong. That is because once a signal dips below the ambient noise floor there isn't much one can do to recover it.

At home, I enjoy listening to "blowtorch" signals like All India Radio, Voice Of Greece and Voice of Turkey (although occasionally I try my luck and listen to weaker stations). Still, sometimes the propagation is poor and even these stronger transmissions start fading into the noise. This can be especially disappointing when I start recording a particular transmission and then go off to do other things, only to find out later that the recording is heavily ridden with static. Many of my night-time recordings have ended up this way and until recently I thought that they were generally beyond "repair".

Enter SDR#. It turns out that it can process a regular audio WAV file just as if it were a real-time radio signal, meaning that its noise reduction plugins can be used to clean up the sound.

SDR# settings for denoising audio. Click the image to enlarge.
To do this, open the WAV recording either as an IQ file or using the FilePlayer front-end plugin. Chose the RAW demodulation mode and click play. You can then experiment with IF Noise Reduction parameters to find a setting that offers a good tradeoff between the noise filter strength and the amount of audio artefacts.

To give an example, here's a rather noisy recording of All India Radio I grabbed last New Year's Eve:

And here it is after noise reduction with SDR#:

Although there are a few DSP audio artefacts in the denoised version, I do like the end result and I'm sure I will be repairing quite a few more of my noisy recording this way. Continue reading →