Tag Archives: Recordings

Propaganda Shift: The Panmunjom Summit and monitoring the Voice of Korea

Front page of the North Korean newspaper “Rodong” on April 28, 2018. (Source: Mark Fahey)

With North Korea in the global spotlight, I’ve been making every effort to listen to the Voice of Korea on shortwave. Unfortunately, from here on the east coast of North America, conditions have simply not been in my favor.

Fortunately, a couple of SWLing Post and SRAA contributors have had my back.

Yesterday, Richard Langley, uploaded a great VOK recording made with the U Twente WebSDR on April 28 at 13:30 UTC on 13760 kHz. Thank you Richard!

This morning, North Korean propaganda specialist Mark Fahey uploaded the following VOK recording to the archive and included notes and insight:

[The recording is] off 9,730 kHz so a mint shortwave file.

Recorded at the “Behind The Curtain” remote satellite and HF receiving site near Taipei, Taiwan (the site is remotely operated from Freemans Reach in Australia and was specifically established to monitor North Korean radio & television 24×7).

Remote Module #1 prior to sealing.

[Note: Click here to read about Mark’s self-contained deployable remote SDR stations.]

Remote Module #2 fully weather sealed and ready to deploy.

[…]I must say getting a good recording off shortwave is quite a challenge, just going to their satellite circuits far easier!

[T]he reason for the almost hi-fi quality is that I used the real-time audio enhancement and noise reduction techniques I presented at the Winter SWL Fest. The signal in reality was much noisier:

Click here to download an MP3 copy of the off-air recording.

[I] also have long domestic recordings (which is what I have been focusing on rather than VOK).

[…]Of course domestic in Korean – but that has been my main interest/monitoring – what does the regime say to the domestic audience–?

They seem quite serious (I mean genuine) even acknowledging South Korea as a separate place and Moon being the president of this place. The domestic propaganda now not hiding the fact that South Korea is a separate sovereign nation, which is very un-North Korean propaganda!

The news is still kind of breaking in North Korea and the radio reflects that – the reports sound like Friday was yesterday. It takes a long time for North Korean media to report anything, so news from 3 days ago is presented as if it only happened 3 hours ago.

Also since it’s all topical I will include a YouTube link to a Voice Of Korea Documentary (propaganda to our ears of course–!) that has recently been posted to the Arabia Chapter of The Korean Friendship Association:

Click here to watch on YouTube.

Thank you, Mark! Certainly history in the making.

Mark Fahey is my go-to guy for what’s really happening in North Korea, especially with regards to the message the government shares with its people.

Though I haven’t asked him in advance, I’m sure Mark can follow the comments thread of this post and answer your North Korea questions.

Click here to leave a comment/question or follow the comments thread.

If you have a recording of VOK (or any other broadcaster) that you would like to share, consider contributing to the SRAA.

Shortwave Radio Recordings: Ham radio contacts between W2PVF (SK) and two Antarctic Stations, circa 1974

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Palmer Station (Photo Credit: Ryan Wallace and the USAP)

Many thanks to Bill Hemphill (WD9EQD) who is one of our newest contributors at the Shortwave Radio Audio Archive (SRAA). Bill approached me at the Winter SWL Fest this year noting that he has a wide variety of radio-related audio recordings to share with the SRAA and the SWLing Post.

This week, Bill shared two fascinating tape recordings he originally acquired from an estate sale box. These recordings were originally made in 1974 by the late Jim Hayward (W2PVF) in Absecon, New Jersey (USA) with two different ham radio stations in Antarctica.

This first recording is between W2PVF and KC4AAC of Palmer Station. The audio starts mid conversation:

Click here to download.

The second recording is between W2PVF and LU1ZE of the Argentine Antarctica Station. The operator at the microphone is W1PV. The recording even includes a phone patch:

Click here to download.

Bill, thanks so much for sharing these recordings–I thoroughly enjoyed them!

I’m so impressed with the audio and signal quality of the Antarctic stations. In 1974, we were approaching a solar minimum in Solar Cycle 20. Still, I bet conditions were better than anything we’ve seen in over a decade!

I’m curious if any Post readers have ever made contact with either of these stations or even know the operators in the recordings? Bill notes that Jim (W2PVF) was president of the local Atlantic City Electric Company for many years. Would be fun to share these recordings with the some of the original operators, if they’re around!

Treasure hunt: Seeking Somali radio recordings from 2010

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Okay SWLing Post readers: I need you to dig through your off-air recordings for something pretty obscure…

Over at the Shortwave Radio Audio Archive, I frequently receive inquiries from educators, researchers, historians, and enthusiasts looking for very specific off-air recordings, often for some worthy project or other. It’s quite a thrill when I can lay hands on just what’s being sought in our rather deep recordings archive.

I recently received just such an inquiry from producer Meghan Keane at NPR, and though we were not able to provide immediate help, I’m quite intrigued by the subject and thus not quite ready to give up the search. Meghan writes:

My name is Meghan Keane and I’m a producer for NPR’s Invisibilia. I’m working on a story about Somalia and music, and am currently looking for some archival sound.

Around 2010, many radio stations in Somalia broadcasted animal noises and gun shot noises to protest Al-Shabab. I am hoping to find audio of that to use in my story. Please let me know if you have any leads!

Fascinating stuff. I do recall a news story about Somali radio broadcasts including animal and gun shot noises back in the day, but I never actually heard a broadcast on shortwave or mediumwave.

Post readers: Can you help Meghan track down such a recording? If you can, please comment and/or contact me!

Results: AirSpy HF+ vs Elad FDM-S2 Weak Signal Comparisions

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Looking north toward Cape Lookout, Oregon, near the site of my SDR receiver recordings. Photo courtesy of Wikimedia Commons.
In my original article 10 days ago, I set up a SWLing Post reader poll to let you give your opinion on which shortwave recordings within four pairs of audio files provided the most intelligible result. The recordings were intentionally noisy, low-level signals to help us discover–through critical listening to the files–if there is a clear favorite between the AirSpy HF+ or the Elad FDM-S2 receivers. Of course, there were only four pairs of recordings…not a very large sample size.

However, 34 readers of the original article took the time to listen and respond, so let’s get to the numbers, shown in these graphs:

Interestingly, the responses above seem to point to:

Two recording pairs tied in the results (50% / 50%) or were very close (HF+ 52.9% / FDM-S2 47.1%)
The FDM-S2 led one recording pair by a large margin (67.6% / 32.4%)
The HF+ led another recording pair by an equally large margin (67.6% / 32.4%)

Taken as a whole, no obvious winner emerged, although one might conclude the HF+ has a slight edge due to its lead in the “very close” recording pair of 7.230 MHz.

One thing is clear–the AirSpy HF+ is a surprisingly good performer for its price of $199 USD! For many enthusiasts this will be all the SDR they need.

As a final note, I’ll mention that the AirSpy HF+ used for the tests was totally stock. I have not yet performed the “R3 Bypass” mod nor the firmware update to my HF+ units. The simple R3 Bypass, discussed at length on the AirSpy Groups.io forum, significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues. For more on this modification from a MW DXer’s perspective, read Bjarne Mjelde’s insightful article at his Arctic DX Blog.

Thank you to all the readers who took the time to listen to the SDR recordings in this comparision and register your opinions.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.

Digging in the Noise: Weak Signal Audio Recovery with the AirSpy HF+ and Elad FDM-S2

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I’m currently spending the better part of a week at Cape Lookout State Park on the Oregon coast, with a great view of the ocean through tall evergreen trees. This is one of my favorite parks in the Pacific Northwest, especially when DXing during the blustery winters from one of the nice cabins at Cape Lookout.

The view from the beach near my cabin; the turbulent waves were a precursor to the gale force winds at the park during the night of the 23rd!

Although I’m at the park for trans-Pacific medium wave DXing, I’m also comparing receivers, both SDRs and portables. This morning I sought out a few weak shortwave signals, pitting the Elad FDM-S2 SDR ($529 USD) against the AirSpy HF+ ($199 USD). I have a pair of the HF+ receivers to cover all of medium wave (as the FDM-S2 easily does). Many SWLing Post readers already know that the upstart HF+ trades bandwidth to gain high performance in order to keep the price reasonable.

My antenna used for the following recordings was a small “Flag” antenna using a Wellbrook Communications FLG100LN module and a 2K ohm variable potentiometer for termination. The design uses crossed tent poles in an “X” formation to support the wire loop. This design travels easily in a compact package; I have Dave Aichelman of Grants Pass, Oregon to thank for this very useful “tent pole loop” implementation of the Wellbrook FLG100LN.

The Wellbrook-based antenna functions superbly, and its low-noise design helps hold down QRM from the nearby cabins (which unfortunately have been “upgraded” recently with noisy cold fluorescent [CFL] light bulbs). The area around the Cape Lookout cabins used to be superbly low noise and suitable for radio listening, but now it is more of a challenge than before. The Wellbrook FLG100LN is perfect for the situation though; Wellbrook ALA1530LN Pro and ALA1530S+ 1-meter loop antennas work commendably at the park too.

The Wellbrook FLG100LN module with a home brew RFI choke in-line

A 2K ohm variable potentiometer is protected from the elements in a small plastic bag. The “pot” is adjusted for the best nulling of medium wave stations off the back side of the antenna’s reception pattern.

The “tent pole loop” antenna is strapped to a fence railing with ultra-strong Gorilla Tape to keep the 7-ft. square loop vertical.

On with the recordings…

For the FDM-S2 and HF+ comparisons I used the SDR-Console V3 software. Every parameter was identical for the receivers–sampling bandwidth, filter bandwidth, AGC, mode and so on.

Take a critical listen to the weak signals recorded with the SDR receivers, identified as only “Radio A” and “Radio B”. A link to a poll is at the end of this article; please indicate which recording of each pair has the most intelligible audio in your opinion, and submit your choices when you’ve made up your mind on each audio clip. After a week or so I’ll post the results of the voting, and identify the receivers.

9.615 MHz, LSB, Radio A

9.615 MHz, LSB, Radio B (note: the same male announcer heard in clip “A” begins at 00:14 in this “B” clip)

9.730 MHz, USB, Radio A

9.730 MHz, USB, Radio B

7.230 MHz, S-AM, Radio A

7.230 MHz, S-AM, Radio B

9.860 MHz, S-AM, Radio A

9.860 MHz, S-AM, Radio B

Note on 7.230 MHz recording: this was an interesting frequency, as the signal was tightly surrounded by a very strong local 40m ham radio LSB station as well as a strong China Radio International signal. There were other strong amateur and broadcast stations within 30-50 kHz of 7.230 MHz, also. This A-B test more than the others may indicate receiver performance in a strong RF environment on a crowded band.

Ready for the poll? Register your votes at the Google Docs form below:

https://tinyurl.com/ya38wj69

In a week to 10 days I’ll post the results in another article. NOTE: I haven’t provided a “both sound the same” choice in the poll to encourage you to ‘dig deep’ into the audio and listen critically–to find something that stands out in one clip versus the other.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.