Japanese ship – coastal station marine comms

 

Concept Diagram of Maritime Communications. Image source: soumu.go.jp

The shortwave frequency range is commonly used for two-way radio communications between ships at sea, as well as between ships and nearby coastal stations across the world. Usually, these are low-power, non-directional transmissions of around 1 kW and can only be heard well locally. For example, in London it is often possible to hear sailors in the territorial waters of France, Spain, Portugal and, occasionally, Greece. I was therefore very surprised when I discovered what appeared to be maritime communications in Japanese on 8261 kHz in a spectrum recording I made on October 10, 2022:

The nature of this transmission was kindly confirmed to me by the user @shinyaradio on Twitter:

Hello. This is a communication between a coast station and a ship station.
The content is numbers and ciphers and I don't understand it.https://t.co/DRWyHnsJ7O

— 長谷川 眞也 (@shinyaradio) October 18, 2022

The link in the tweet states that this frequency is indeed allocated for maritime communications in Japan and the power of these transmissions should not exceed 1.2 kW. If this transmission did in fact originate in Japan, the propagation conditions must have been truly excellent that evening!

Another momentous day on captured on shortwave

 

October 24th marked another day of significant international developments covered on shortwave. Rishi Sunak became the fifth Conservative UK Prime Minister in just over six years and the Chinese Communist Party concluded its 20th National Congress two days earlier. Below is a selection of news broadcasts extracted from the spectrum capture I made outdoors, starting from around 1600 UTC. The BBC World Service coverage expectedly focused on Rishi Sunak's ascent to the prime minister's office, while the KBS World Service (South Korea) aired a long discussion on the party congress in China. The Voice of Vietnam and China Radio International brodcasts were also noteworthy in terms of how they placed emphases on these and other important events of the day. The spectrum capture was made using GPD MicroPC, AirSpy Mini, SpyVerter 2, Wellbrook UMB130 balun and a 2x6m dipole. Demodulation and additional signal audio enhancement was performed in SDR#.

BBC World Service reporting on the death of Queen Elizabeth II

The recordings below were made on September 8, 2022 at 1928 UTC on 7445 kHz, and at 1959 UTC on 12095 kHz, using GPD MicroPC, AirSpy Mini, SpyVerter 2, Wellbrook UMB130 balun and a 2x6m dipole. Demodulation and additional signal audio enhancement was performed in SDR#.

Amateur Radio Newsline Report 2339 on Shortwave Gold

 

From the Amateur Radio Newsline website:

Amateur Radio Newsline™ is a free service to the amateur radio community.  We produce a weekly audio news bulletin called a “QST” or “bulletin of interest to radio amateurs” that is delivered by a downloadable MP3 audio file from our website or through a podcast subscription.  Operations are supported primarily by voluntary donations from individual amateurs and amateur radio clubs.

Below is a recording of their audio bulletin for August 26th, 2022, broadcast on Shortwave Gold on August 30, 2022 at 1703 UTC:

I extracted this recording from an outdoor spectrum capture I made using GPD Win, AirSpy HF+ Discovery, Wellbrook UMB130 balun and a 2x6m dipole.

North Korea officially announces its first COVID-19 outbreak

 

Quoting The Diplomat:

For the first time, North Korea has confirmed a positive COVID-19 case within the country. The state-run Korean Central News Agency reported on May 12 that a “specimen from persons with fever” in Pyongyang had come back positive for the Omicron BA.2 variant, a particularly contagious strain of the virus. The phrasing of the announcement makes it unclear how many people are infected. KCNA called the development a “most serious emergency case of the state.”

By complete chance, I found this very announcement in the Voice of Korea's English language transmission that I managed to record during one of my regular outdoor spectrum capture outings:

I made this spectrum capture on May 12, 2022 using GPD MicroPC, AirSpy Mini, SpyVerter 2, Wellbrook UMB130 balun and a 2x6m dipole.

The Voice of Korea reporting on the launch of the Hwasong-17 intercontinental ballistic missile

 

For the past four weeks I have been regularly archiving the shortwave coverage of the war between Russia and Ukraine, and my posts summarising these recordings will appear on this blog shortly. Meanwhile, below is a recording of the DPRK's Voice of Korea announcing the launch of the of the Hwasong-17 intercontinental ballistic missile:

I extracted this recording from an outdoor spectrum capture I made on March 25, 2022 using GPD MicroPC, AirSpy Mini, SpyVerter 2, Wellbrook UMB130 balun and a 2x6m dipole.

Shortwave gems special: Electronic music on the 40m amateur radio band

Lately, I have been able to make more frequent outdoor trips for recording parts of the shortwave radio spectrum using my portable set-up. While reviewing one such recording from August 31st, 2021, I noticed something highly unusual: a continuous music mix on one of the amateur bands, modulated as a lower single sideband audio signal. For readers who are unfamiliar with radio communication regulations, broadcasting music is strictly prohibited on all amateur bands in most jurisdictions. However, it turns out that the frequency in question – 7055 kHz – has now been used for some years by a number of hams for antagonistic on-air exchanges. It is likely that, in an act of desperation, someone had decided to put a stop to that (at least temporarily) by relentlessly broadcasting music using their single sideband transceiver.

Here's some trance music on 7055 kHz. Recorded on 31/08/21 at 1722 UTC with #AirSpy Mini / SpyVerter 2, 2x6m dipole. https://t.co/YytzXh6E2Q pic.twitter.com/5vzFxcAlET

— London Shortwave (@LondonShortwave) September 2, 2021

The music itself is a mixture of trance, ambient house and drum & bass, but what makes this recording truly special are the various amateur radio artefacts that get superimposed onto it, such as morse code and other non-voice communications. To my ears, this gives the transmission the atmospheric feel that is so emblematic of shortwave radio in general, although perhaps in a somewhat exaggerated form. Below is the full recording for your listening pleasure: