Radio Kuwait's DRM transmission in English

Saturday, July 21, 2018
Kuwait City
Below is a 30 minute recording of a Digital Radio Mondiale transmission from Radio Kuwait. Roughly speaking, DRM broadcasts are the shortwave (long distance) equivalent of DAB radio, where the audio is encoded digitally to save bandwidth, and — in the case of DRM — improve audio quality. This DRM stream was decoded from an outdoor spectrum recording made on 20/07/18 at 1830 UTC using my ultra-portable spectrum capture set-up. The program starts with the news, followed by western pop music. The video contains diagnostic information in the form of the DRM signal-to-noise ratio (SNR) and dropped audio frames. Although DRM broadcasts are usually more challenging to pick up than their analogue counterparts, I would classify this reception as excellent.

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Shortwave gems: June 2018

Friday, June 29, 2018

Three very interesting tracks I found in my spectrum recordings this month:

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From nuclear tests to a summit with the USA: monitoring North Korea-related news on shortwave

Friday, June 15, 2018

This post breaks with tradition in that the news events it mentions are listed backwards in time. The post is a collection of recordings I made off shortwave, reflecting significant milestones in the North Korean nuclear crisis to date. The recordings were made between September 3, 2017, when the DPRK conducted its sixth and most powerful nuclear test to date, and June 13, 2018, when the North Korean state media reported the meeting between Kim Jong Un and the 45th US President, Donald Trump, one day after the event.

13/06/18: North Korea finally reports the meeting between Kim Jong Un and Donald Trump

Voice of Korea on 15245 kHz, recorded outdoors in London, UK on 13/06/18 at 1308 UTC using my portable spectrum capture set-up.

Voice of America's news bulletin, captured immediately following the above broadcast. 15580 kHz recorded outdoors in London, UK on 13/06/18 at 1400 UTC using a Tecsun PL-310 radio and a clip-on long wire antenna.

12/06/18: the North Korea summit in Singapore — the world media react (apart from North Korea)

All recordings were made outdoors in London, UK using my portable spectrum capture set-up.

28/04/18: Kim Jong Un crosses the demarcation line between North and South Korea in Panmunjom

The recording was made outdoors in London, UK using my portable spectrum capture set-up.

September 2017: North Korea conducts its sixth nuclear test

07/09/17: North Korea issues a list of demands to the international community

03/09/17: North Korea announces its sixth nuclear test

As above, the recordings were made outdoors in London, UK using my portable spectrum capture set-up. Continue reading →

Music on the Kazakh service of China National Radio

Sunday, April 15, 2018

Below is a 50 minute recording of a music programme broadcast on China National Radio's Kazakh service (a.k.a. CNR channel 17), consisting entirely of Kazakh songs.

I extracted the above from an outdoor spectrum recording I made with my portable spectrum capture set-up. Continue reading →

Somali music on the Voice of America

Monday, January 01, 2018

The other day, while recording portions of the shortwave spectrum out in the park, I stumbled across a faint Voice of America broadcast in Somali with lots of music, which I rather liked.

Below is the full recording for your listening pleasure. Voice of America (Somali), recorded outdoors on 15620 kHz, on 30/12/17 at 1325 UTC using AirSpy R2, SpyVerter 2.0 and a 2x6m dipole.

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New Year, new endeavours: ultra-portable shortwave spectrum captures in 2018

Monday, January 01, 2018
GPD Win, AirSpy HF+ and Tecsun PL-310ET
Hello and Happy 2018 to all the readers of the London Shortwave blog!

This post comes after a relatively long hiatus, as new work commitments starting last summer reduced the amount of time I could spend on shortwave radio listening. Longer working days and commute periods gradually encroached on the time slots that I had previously allocated for going to the park to record parts of the shortwave spectrum. (On the other hand, owing to continuously increasing urban RFI, my indoor reception conditions have deteriorated to the point of being essentially unsuitable for any serious radio listening).

However, just as I found myself under these new time constraints, my friend Thomas Witherspoon contacted me to tell me about his new initiative, The Spectrum Archive, and kindly invited me to become part of the team (which I gratefully accepted!). From the project website:

The Radio Spectrum Archive (RSA) allows listeners to experience radio history as it happened. It offers listeners the ability to tune through a radio band, listening not only to individual stations, but to all the stations in broad swathes of recordings, providing richly relevant radio context from the time. 
The Spectrum Archive team actively creates new spectrum recordings and maintains existing spectrum recordings for current and future use by, among others, historians and researchers.

The opportunity to contribute to this unique project renewed the impetus for me to find a way to create outdoor shortwave spectrum captures on the go without having to make return trips home to drop off my relatively bulky recording equipment.

PocketCHIP and FunCube Dongle Pro+ (September 2017)

My first attempt at this was to use the PocketCHIP portable computer and the FunCube Dongle Pro+, together with the Sony AN LP-1 foldable active loop antenna:

The idea was to have a spectrum capture set-up that could fit into the side pocket of my laptop bag and be quickly deployed in any open space.

PocketCHIP runs Linux, for which there are plenty of SDR applications, however, because of CHIP's limited CPU capabilities it is difficult to get any of them to run glitch-free. As a result, it's possible to inspect the spectrum visually prior to starting the recording but it's impossible to do both at the same time and there is currently no way of monitoring the audio while the recording is underway.

On Linux, FunCube Dongle Pro+ can be accessed without any SDR application running in the background (a big advantage given PocketCHIP's limitations): the dongle uses the sound card I/O interface and a simple audio recording utility such as ecasound can be employed to record the I/Q data stream to disk. However, the main drawback of this dongle is that it can only capture 192 kHz at a time, making it impossible to record an entire shortwave band in one go. On the other hand, PocketCHIP's battery life is around five to six hours, far longer than that of any of my laptops or tablets.

GPD Win and AirSpy HF+ (November 2017)

In November I received a sample of AirSpy HF+ — a very sensitive, compact SDR, capable of recording an entire shortwave band in one go. I used it to form an alternative ultra-portable capture set-up: the antenna is still the Sony AN LP-1 compact loop but the PocketCHIP is replaced with a similarly-sized GPD Win: a fully functional 5-inch (!) Intel PC running Windows 10:

AirSpy HF+ is tightly integrated with SDR# — a Windows application — which ended up being the main rationale for getting one of the most portable Windows computers out there and putting it to the test. After a bit of tweaking and experimentation (which I'll describe in detail in one of my next posts) I managed to get it to work. GPD Win's CPU is capable of running SDR# without any problems, its battery lasts around 4 hours when recording the spectrum and the Sony loop antenna proved to be very sensitive indeed:

The above two recordings were made with the GPD Win / AirSpy HF+ / Sony loop combination on Christmas eve in a London park, and the quality easily rivals that of the captures I have made with my regular outdoor set-up under similar propagation conditions.

I hope the greater portability will allow me to continue making outdoor spectrum recordings under increased time pressure. Thanks for reading and wishing you all a great year with lots of interesting radio catches!

GPD Win, AirSpy HF+, Bonito GI300 isolator and the Sony AN LP-1 loop antenna preamp out in the field

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