Category Archives: Recordings

Paul’s recording of “La Voix de la Corée” interval signal and broadcast intro

Many thanks to SWLing Post contributor, Paul Jamet, who writes:

Hello Thomas,

I hope everything is fine.

To complete Carlos Latuff’s contribution, here is a recording of the French language program of “La Voix de la Corée” made the afternoon of May 30, 2022 at 14h00 UTC on the frequency 13760 kHz with a TECSUN PL-365 connected to a 5m wire antenna of about 5 meters length.

Recording:

I attach the picture of the receiver on an old wall (see above); the screen displays the frequency and the signal characteristics: Signal strength unit: 27 dBu – Signal to Noise Ratio (S/N) unit: 08 dB

The other frequency used at the same time is 15245 kHz but I could not hear anything!

I hope that this information will hold your attention. See you next time. Sincerely yours.

Paul JAMET
Radio Club du Perche :
http://radioclub.perche.free.fr/

Thank you for sharing your recording, Paul!

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Carlos’ Shortwave Art and recording of the Voice of Korea (May 26, 2022)

Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art of a recent Voice of Korea broadcast.


Carlos notes:

Part of news bulletin from Radio Voice of Korea shortwave broadcast in English about efforts of North Korea’s government to fight covid-19 pandemic.

Listened in Porto Alegre, Brazil, May 26, 2022, 21h09 (UTC), frequency of 15245 kHz.

Click here to view on YouTube.

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Matt’s Rooftop Receiver Shootout: Round Two!

Many thanks to SWLing Post contributor, Matt Blaze, for the following guest post:


Matt’s Rooftop Receiver Shootout, Round Two.

by Matt Blaze

You may recall that back in April, I dragged eight of my favorite receivers up to the roof, hooked them up to a portable antenna, and compared their abilities to demodulate various signals at the same time. For the most part, the similarities between radios were more striking than their differences. I hinted that there’d be a second installment to come, including more receivers and more challenging signals, to further expose and highlight the practical real-world performance differences between the radios we use.

So, as promised, here we are with Round Two of my Rooftop Receiver Shootout.

This time around, I used approximately the same setup, but with a total of fifteen different radios. And once again, I took advantage of nice weather and brought a multitude of receivers, recording gear, cables, and an antenna up to my roof to listen to and record shortwave signals under the open sky.

Our fifteen receivers included everything from “dream radios” from the 1980’s to current-production desktop models to less expensive modern portables to high-performance bench-top lab measurement gear. I tried to curate samples of a wide range of radios you may be familiar with as well as some you probably aren’t.

The lineup consisted of:

  • Icom R-8600, a current production “DC to Daylight” (or up to 3 GHz, at least) general coverage communications receiver, with highly regarded shortwave performance.
  • AOR AR-ONE, another DC to 3 GHz general coverage radio, less well known due to the high price and limited US availability. Excellent performer, but a counterintuitive and awkward (menu-driven) user interface is less than ideal for shortwave, in my opinion.
  • Reuter RDR Pocket, a very cute, if virtually impossible to get in the US, small production, high performance SDR-based shortwave portable receiver. It’s got an excellent spectrum display and packs near desktop performance into a surprisingly small package.
  • AOR 7030Plus, an extremely well regarded mobile/desktop HF receiver from the late 90’s. Digital but retaining some important analog-era features like mechanical filters. Designed and (mostly) built in the UK, it’s got a quirky menu-driven user interface but is a lot of fun once you get used to it.
  • Drake R8B, the last of the much-beloved Drake receivers. Probably the chief competitor to the 7030+.
  • Drake R7A, an excellent analog communications receiver (but with a digital VFO) from the early 80’s. It still outperforms even many current radios.
  • Sony ICF-6800W, a top of the line “boom box”-style consumer receiver from the early 80’s. Great radio, but hard to use on SSB, as we saw in Round One.
  • Panasonic RF-4900, the main competition for the Sony. Boat-anchor form factor, but (improbably) can run on internal D-cell batteries. Generally impressive performer on AM, but, like the Sony 6800, difficult to tune on SSB.

You may remember the above radios from Round One back in April. The new radios this time were:

  • Tecsun 501x, a larger-format LW/MW/HF/FM portable released last year. As noted below, it’s a generally good performer, but regrettably susceptible to intermod when connected to a wideband external antenna (as we’ll see in Part One).
  • Tecsun PL-990x, a small-format portable (updating the PL880), with many of the same features as the 501x. Like the H501x, good performance as a stand-alone radio, but disappointing susceptibility to intermod when fed with an external antenna.
  • Sangean ATS-909x, a recent LW/MW/HF/FM portable with a good reputation as well as a few quirks, such as only relatively narrow IF bandwidth choices on HF. Excellent performance on an external antenna.
  • Sangean ATS-909×2, an updated, current production version of the ATS-909x that adds air band and a few performance improvements. Overall excellent, though I would prefer an addition wider IF bandwidth choice. My go-to travel receiver if I don’t want to take the Reuter Pocket.
  • Sony ICF-7600GR, a small-format digital LW/MW/SW/FM portable introduced in 2001 and the last of the Sony shortwave receivers. Showing its age, but still competitive in performance.
  • Belka DX, the smallest radio in our lineup, made in Belarus. You’ll either love or hate the minimalist interface (one knob and four buttons). If you’re going to secretly copy numbers stations in your covert spy lair, this is a good radio to use. Can be difficult to obtain right now due to sanctions.
  • Finally, a bit of a ringer: the Narda Signal Shark 3310, a high performance SDR-based 8.5 GHz RF spectrum and signal analyzer. As with most test equipment like this, demodulation (especially of HF modes) is a bit of an afterthought. But it has an excellent front end and dynamic range, intended for identifying, extracting, and analyzing weak signals even in the presence of strong interference. Not cheap, but it’s intended as measurement-grade lab equipment, not consumer gear. Demodulated audio is noticeably delayed (several hundred ms) compared with other receivers due to the multi-stage DSP signal path.


The antenna was my portable “signal sweeper” Wellbrook FLX-1530 on a rotatable tripod, using a power splitter and a pair of Stridsberg Engineering 8-port HF distribution amplifiers to feed the fifteen radios. So every radio was getting pretty close to exactly the same signal at its RF input. Continue reading

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Carlos’ Shortwave Art and recording of the Voice of Korea (May 23, 2022)

Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art of a recent Voice of Korea broadcast.


Carlos notes:

Part of news bulletin from Radio Voice of Korea shortwave broadcast in English about efforts of North Korea’s government to fight Covid-19 pandemic.

Listened in Porto Alegre, Brazil, May 23, 2022, 21h18 (UTC), frequency of 15245 kHz.

Click here to view on YouTube.

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Matt’s 2022 Rooftop Receiver Shootout!

Many thanks to SWLing Post contributor, Matt Blaze, for the following guest post:


2022 rooftop receiver shootout

by Matt Blaze

I realized it’s been long past time for me to do another head-to-head receiver comparison “shootout”, where you can compare the audio from multiple radios receiving the same signal at the same time. Long time readers of Thomas’ blog may remember I’ve posted a few of these before.

So I took advantage of the nice weather and brought a bunch of radios, recording gear, and an antenna up to the roof to listen and record signals under an open sky. My neighbors, no doubt, wondered what I must have been up to. (Don’t tell them I’m just a harmless radio nerd.)

This year, our focus is on eight “dream receivers” from the 1980’s to the present. Each radio is at or near the top of the line in its class at the time of its release. Our radios include, in roughly reverse chronological order:

  • Icom R-8600, a current production “DC to Daylight” (or up to 3 GHz, at least) general coverage communications receiver, with highly regarded shortwave performance.
  • AOR AR-ONE, another DC to Daylight general coverage radio, less well known due to the high price and limited US availability. Excellent performer, but a terrible (menu-driven) user interface for shortwave, in my opinion.
  • Reuter RDR Pocket, a very cute, if virtually impossible to get in the US, small production, high performance SDR-based shortwave portable receiver. It’s got an excellent spectrum display and packs a lot of performance into a surprisingly small package.
  • AOR 7030Plus, an extremely well regarded shortwave receiver from the late 90’s; designed in the UK. It’s got a quirky menu-driven user interface but is a lot of fun to use.
  • Drake R8B, the last of the much-beloved Drake receivers. Probably the chief competitor to the 7030.
  • Drake R7A, an excellent analog communications receiver (but with a digital VFO) from the early 80’s. It still outperforms even many current radios.
  • Sony ICF-6800W, a top of the line “boom box” style consumer receiver from the early 80’s. Great radio, but hard to use on SSB.
  • Panasonic RF-4900, the main competition for the Sony. Boat-anchor form factor, but runs on batteries. Excellent performer, but also hard to use on SSB.

The radios were fed from my portable Wellbrook FLX-1530 antenna, using a Stridsberg Engineering HF distribution amplifier. So every radio was getting pretty close to exactly the same signal at its RF input.

Recordings were taken from the line output, if one was available, or the external speaker/headphone output otherwise. In either case, the audio was then isolated and converted to a balanced signal for recording.

For each signal, I recorded monaural “solo” tracks for each radio, as well as a narrated stereo track in which I compared the audio from each radio (one after the other) against the Icom R8600, with the audio from the R8600 on the left channel and the audio from the other radios on the right channel. This gives you a quick overview of what all the radios sound like.

The stereo recording requires some explanation. For it to make any sense, you MUST listen in stereo, using decent headphones if at all possible. You can switch earpieces back and forth (with your finger on pause and rewind) to get a quick idea of what each radio sounds like compared with a modern receiver, and how they handle things like fades and static.

The solo tracks, on the other hand, consist entirely of the continuous audio from a single radio, with no narration or interruption.

I recorded three different signals, for a three part comparison. (Parts four and up will come, hopefully, soon). I think both the differences and similarities will surprise you.

Part One

Our first signal was the BBC on 9915 KHz, broadcasting from Madagascar to western Africa. This signal was extremely marginal here, intended to show how each receiver can or can’t handle signals down in the noise. It’s definitely not “armchair copy”.

The stereo overview is at:

The individual receiver solo tracks can be found here:

Icom R-8600:

AOR AR-ONE:

Reuter RDR Pocket:

AOR 7030Plus:

Drake R8B:

Drake R7A:

Sony ICF-6800W:

Panasonic RF-4900:

Part Two

Our next signal was the Shannon (Ireland) aviation VOLMET broadcast on 5505 KHz USB. This synthesized voice gives the latest meteorological conditions at airports around Europe. The signal was not strong, but entirely readable. It shows how the radios handle a weak SSB signal. Note that the Sony and Panasonic consumer radios, though equipped with a BFO, were VERY hard to tune properly.

The stereo overview is at:

Receiver solo tracks can be found here:

Icom R-8600:

AOR AR-ONE:

Reuter RDR Pocket:

AOR 7030Plus:

Drake R8B:

Drake R7A:

Sony ICF-6800W:

Panasonic RF-4900:

 

Part Three

Our final signal was a stronger, though occasionally fading, shortwave broadcaster, Radio Romania International on 13650 KHz AM. This gives you a sense of how the receivers performed on a typical “average” signal that you might actually want to enjoy listening to. Because the radios have different filters and other capabilities, I tuned each radio to whatever sounded best; I did not attempt to use comparable settings (since no common settings existed).

The stereo overview can be found at:

And the individual solo tracks are here:

Icom R-8600:

AOR AR-ONE:

Reuter RDR Pocket:

AOR 7030Plus:

Drake R8B:

Drake R7A:

Sony ICF-6800W:

Panasonic RF-4900:

Subsequent comparisons, hopefully soon, will focus on receiver performance on signals in crowded bands and under various kinds of interference and noise.

A quick note on production: The recordings were made with a 12 channel Sound Devices 833 recorder with a Sound Devices SL-16 mixing console. The audio was isolated and converted to balanced output with Switchcraft 318 direct interface boxes (highly recommended for recording radios with pro audio gear).

The stereo track narration was done by me in real time, as the signals were being recorded. I made some comments about which receivers I thought sounded best that were not always the same as what I would later conclude after carefully listening to the solo tracks once back inside. But judge for yourself. I used a Coles “lip” microphone, an amazing ribbon mic designed decades ago for the BBC for use in highly noisy environments. It was very effective in reducing the sometimes considerable street noise and other ambient outdoor sounds.

Thanks for listening and 73!

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Radio Prague: 1965 20th Anniversary of the Liberation of Czechoslakia 7″ record

Many thanks to SWLing Post contributor, Mike Barraclough, who shares the following partially in response to Sam’s search for the Radio Prague’s Forward Left interval signal:


In 1965 on the occasion of the 20th anniversary of the liberation of Czechoslovakia Radio Prague offered their listeners a free copy of a 45rpm record they’d produced. There were 5 versions issued with commentaries in German, English, French, Italian and Spanish. Information and images here, at the time of writing there are two copies of the French edition for sale from record dealers.

https://www.discogs.com/artist/463619-Radio-Prague-2

I’ve digitised my copy of the English one I received.

Side One

Side One Recording

Side One has a recording of their interval signal at the time and the Communist Anthem Forward Left it is taken from.

Side Two

Side Two Recording

Side Two The Road to Freedom has an account of the liberation of Czechoslovakia in early May 1945 and the role of Radio Prague during it with recordings of their broadcasts, including one in English, at the time.

I’ll be submitting a slightly expanded account of this to the British DX Club for next month’s bulletin as picking up Radio Prague and other English language stations from abroad on mediumwave such as Radio Moscow was the reason I bought a shortwave receiver. Living on the East Coast of the UK I could pick up AFN Bremerhaven daytime as well as a Dutch station Radio Veronica playing pop records all day as an alternative to the BBC. Radio Luxembourg, which you’ve most likely heard of, for nightime listening. Will check, think it would be early 64 when I bought my first shortwave receiver.

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Carlos’ Shortwave Art and recording of the Voice of Korea (April 17, 2022)

Many thanks to SWLing Post contributor and noted political cartoonist, Carlos Latuff, who shares his radio log art of a recent Voice of Korea broadcast.


Carlos notes:

Voice of Korea, 15245 kHz, broadcasting in English, listened in Porto Alegre, Brazil, April 17, 2022, 21h08 (UTC).

Part of news bulletin: Kim Jong-un observes new missile test.

Click here to view on YouTube.

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