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

Sunday, September 26, 2021

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.

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:


Shortwave pirate activity on 21/08

Sunday, August 22, 2021


Without any further introduction, below are three shortwave pirate radio transmissions, extracted from an outdoor spectrum capture I made yesterday with a GPD Win handheld laptop, AirSpy HF+ Discovery and a 2x6m dipole antenna. The music is mostly rock and oldies, which are the staple genres of European shortwave pirates. I hope you enjoy these recordings!


Monitoring the fall of the U.S.-backed Afghan government on shortwave

Tuesday, August 17, 2021


This post comes on the heels of the takeover of Kabul by the Taliban. When it became clear on Sunday that the U.S.-backed Afghan government would be unable to sustain itself against the Taliban's rapid advance into the capital city, I grabbed my portable SDR-based spectrum capture combo and headed to a nearby park. The set-up comprised of my newly purchased GPD MicroPC, AirSpy Mini, SpyVerter 2 and the 2x6m dipole antenna, which I managed to spread out across some tree branches. Using this set-up I was able to make a 3-hour long, 6 MHz wide recording between 1600 and 1900 UTC. This included the 39, 31 and 25 metre bands in their entirety. Below is a preview of what the tail end of that recording looked like when played back in SDR#:

When I returned home, I quickly scanned the spectrum capture to identify the most relevant individual shortwave transmissions. These turned out to be the BBC World Service in English and Pashto, out of Singapore, the Voice of America Deewa Radio, also in Pashto and out of Udon Thani, Thailand, and a new and seemingly unidentified transmission in Dari on 7600 kHz, continuously mentioning the Taliban. I chose 1800 UTC as the starting time for extracting individual station recordings, as by then the presidential palace had already been captured.

The BBC World Service in English has an eerie ending, as the Voice of America in Korean goes live on the same frequency before the BBC's broadcast is finished. Almost two days later, the mystery transmission on 7600 kHz was identified by Alokesh Gupta as the audio feed of Afghanistan International Television, run out of the UK by Volant Media:

The next day, I returned to the same spot – this time with a GPD Win handheld laptop, AirSpy HF+ Discovery and the same 2x6m dipole antenna as I used on the previous day. I recorded the 39 metre band between 1700 and 1900 UTC, for which HF+ Discovery offered much greater sensitivity. When I returned home, I extracted the same stations as the day before, starting at the same time:

Unfortuately I do not understand Pashto or Dari, so cannot fully appreciate most of the broadcasts that I have recorded. However, I hope they turn out to be of value and historical significance to those who speak these languages.


RNZ Pacific's coverage of Auckland's new COVID-19 community transmission case

Monday, February 15, 2021

From Reuters:
A coronavirus outbreak that sent New Zealand’s biggest city into a snap lockdown over the weekend involved the more transmissable UK variant, health officials confirmed on Monday, the first time the strain has been detected locally.

Auckland’s nearly 2 million residents were plunged into a new three-day lockdown on Sunday after three new COVID-19 cases were detected in the city.

Genome sequencing of two the cases - all three are immediate family - revealed they were the B1.1.7 variant. The source of the cases remains unknown, authorities said, adding they were scanning international genome databases for a match.

I used my Belka-DX to grab RNZ Pacific's 10pm broadcast, which covered this story in detail, including a lengthy listener-led Q&A session with a local epidemiologist. I got my Zoom H1 recorder to capture Belka's I/Q output, which I then demodulated in SDR#.