Author Archives: Thomas

Mark records “Pyongyang’s 6 am wake up call”

This week, SWLing Post contributor, Mark Fahey, was featured in the NK News for his research in North Korea. While Mark has made a wide array of his work available through a media-rich (free) iBook, this particular article focuses on the “Morning Chorus” heard throughout Pyongyang in the early hours of the morning:

(Source: NK News)

Why does an eerie electronic ballad play across North Korea’s capital every morning?

It was early in the morning, but Mark Fahey had been awake for hours. A biomedical engineer turned North Korean propaganda expert, he had spent most of the night tinkering with a radio in his room at the Yanggakdo International Hotel, secretly recording the opening moments of Pyongyang FM Pangsong.

While he listened to the station’s typical offering of classical music and propaganda, another microphone and recorder were set up next to an open window to capture the sounds of the city as it roused itself awake. It was August 2011, and the sun hung low on the horizon. Fahey expected to pick up the sound of the dredging work taking place along the Taedong River.

Instead, he heard music.

“Pyongyang is deadly silent at night,” Fahey tells NK News. “If a lorry’s just passing through the city, you’re going to hear it. It’s so quiet. And at 6 am, you hear this kind of weird…” he hesitates. “It sounds like mind control music.”

Seeking an explanation, Fahey brought the tune up with his minder.

“They didn’t know what I was talking about,” he recalls, “but I don’t actually think that means they didn’t know what it was. They probably didn’t realize that I could hear it from where I was.”[…]

Click here to continue reading the full article at the NK News.

The NK News article is fascinating and also includes several more video clips from North Korea media.

Also, consider downloading Mark’s interactive iBook Behind The Curtain from the Apple store by clicking here.

The Itty Bitty Radio Telescope Kit

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(Source: The SETI League)

Many thanks to SWLing Post contributor, Troy Riedel, who writes:

You know my amateur astronomy background. And With the building interest in next month’s Solar Eclipse – and your recent posting from Sky&Telescope re: “How to watch the solar eclipse with your AM radio” – I thought this might be of interest if you haven’t see it yet.

Introducing: “The Itty Bitty Radio Telescope”

Background is here:
http://www.setileague.org/articles/lbt.pdf

Here’s a guide written for teachers as a class project:
http://www.aoc.nrao.edu/epo/teachers/ittybitty/procedure.html

Here’s a guide for building one yourself:
http://www.stargazing.net/david/radio/itty_bitty_radio_telescope.html

And here’s a pre-assembled kit off eBay:
https://goo.gl/HnLUu2

Thank you for sharing this, Troy! I’m amazed at how affordable simple radio telescopes have become. In the 1990s, I was absolutely fascinated with the SETI League’s Project Argus and had planned to build a telescope, but the parts (including an Icom IC-7000) easily totaled over $1,000 at the time–too much for a college student! I imagine a proper Project Argus scope can be built for less than $300 today. Perhaps it’s time to reconsider!

Thanks again, Troy!

RadioWorld free eBook: Global Digital Radio

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(Source: Radio World via Dennis Dura)

Digital radio continues to progress at a rapid pace worldwide. The latest Radio World International eBook, “Global Digital Radio,” takes a look at how each region is preparing for the transition, planned FM switchoff dates and requirements, ways in which digital radio can pave the way to the connected car, how digital radio’s emergency warning functionality can provide relief in times of disaster, and more.

Learn more in the latest free Radio World International eBook. Read it free
now — click here!

Produced by the editors of RADIO WORLD INTERNATIONAL.

Video: Paul’s large aperture “Volleyball Net” loop antenna

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Many thanks to SWLing Post contributor, Paul Walker, who shares the following video and notes:

Here is a 10 minute narrated, detailed video on my 25 foot long by 10 foot tall “Volleyball Net” Loop antenna using a Wellbrook ALA100LN amp control head and antenna interface.

https://www.youtube.com/watch?v=ICHNlcLhAKE

Click here to view on YouTube.

Great job, Paul!

I like how Paul is using the antenna space he has so effectively. Though he has no antenna restrictions, his mag loop can be deployed and taken down quite easily; it’s obviously serving him well on both the HF and mediumwave bands. As he mentions, it’ s also manually steerable.

Those of you with the Wellbrook ALA100LN amplifier might try building this loop as well.

I also like how Paul is using the Tecsun ICR-100 recorder. Not only does it provide an easy way to record line-in audio from his radio, but the built-in speaker serves as an excellent monitor. It’s pretty affordable, too.

I agree with Paul about the Emtech ZM-2 ATU: it’s an exceptional little tuner that can be used for both QRP and SWL applications. I recently purchased the ZM-2 after having borrowed one from my buddy Eric (WD8RIF). Great value, in my opinion.

Thanks again, Paul!

Post readers: If you have an antenna design you’d like to share, please comment or contact me.

Guest Post: Old School Infrared Wireless Headphones

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Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), who shares the following guest post:

Old School (Infrared) Wireless Headphones

by Mario Filippi (N2HUN)

Have you ever mindlessly walked away from your TV with headphones/ear buds still tethered, causing all sorts of havoc? Been there, done that hi hi! Let’s face it; there are plenty of avenues to remedy the situation by upgrading to wireless headphones. Nowadays most state of the art wireless headphones use radio frequencies to achieve a wireless method of listening. For example, my XYL blissfully listens to TV audio with Sony stereo wireless headphones, using a frequency of 915.5 MHz; below is the actual signal viewed with an RTL-SDR dongle.

Sony wireless headphones signal viewed via a SDR dongle; FM modulation.

But hold the presses: there’s good news for folks not averse to old-school technology.

I recently purchased a set of RCA wireless headphones using infrared technology from shopgoodwill.com. Yes, those of us who are somewhat long in the tooth remember infrared as the common method for consumers to “cut the headphone cord” way back when. Infrared is located just above the radio frequency spectrum starting around 300 Gigs (Gigahertz) and is still commonly used in TV and satellite remotes, but less so now with modern wireless headphones operating in the 900 MHz and 2.4 GHz ISM (Industrial, Scientific, Medical) bands.

Admittedly, the new breed of wireless headphones possesses an array of options not available with older infrared units, but if you are satisfied with a no-frills method of headphone freedom (well about 25 feet range that is), check out the pre-owned inventory offered on shopgoodwill.com. The pair I purchased started at $7.99 with no other interested bidders so the total with shipping was $16.82 with the original box and was complete, including the rechargeable NiCad batteries which still functioned but undoubtedly will need replacing. To boot, the money went to a charitable organization.

Wireless IR stereo headphones from shopgoodwill.com

Interestingly, I tried using the wireless IR headphones in conjunction with a shortwave receiver (Panasonic DR22) but there was lots of interference, evidently from the IR transmitter; shortwave and the AM BCB were wiped out by the interference. Now on the FM BCB it worked fine. Even tried it with a scanner and it seemed to work well with FM transmissions (police, fire, EMS) but not with aero AM (108 – 136 MHz).

In the end my venerable older headphones have been relegated to the “shelf of infrequently utilized equipment.” Radio hobbyists might want to visit www.shopgoodwill.com as there are lots more radio memorabilia for window shopping or adding to one’s armamentarium. Remember to read the descriptions carefully as to the working condition. In the interest of full disclosure, I am not associated with ShopGoodWill in any way except that I’m a very satisfied customer. And yes, there are new, state-of-the-art wireless headphones available at a comparable price, so why the reason for this tale? Well, for knowledge, a little history, and a dash of sentimentality, that’s all! hi hi!

Thanks, Mario!

I briefly worked in a RadioShack store in the mid 1990s. We had a set of IR wireless headphones on display and hooked up to a receiver. I remember putting them on and listening to music after/before store hours completing mindless tasks like inventory, clean up, etc. It felt incredibly liberating to walk around the store without a headphone cord umbilical cord! The IR footprint covered the entire store, but fell apart if I had to duck below an end-cap or shelf partition.

Thank you for taking us on a wireless stroll down memory lane, Mario!

FCC Chairman Ajit Pai questioned about pirate enforcement

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FCC Chairman Ajit Pai

(Source: Tom Taylor Now newsletter)

FCC staff will be “cops on the beat” against pirates.

Chairman Ajit Pai had his stats ready for yesterday’s House Oversight Hearing – the FCC’s issued 39 NOUOs (Notice of Unlicensed Operation) this year, among other enforcement actions. Pai knew the question about the effect of closing of 11 field offices was coming from somewhere, and it was posed by Tampa-area Republican Rep. Gus Bilirakis. Pai says as a Commissioner, “I had substantial disagreements with the original” plan of then-Chair Tom Wheeler. The compromise worked out with Congress included closing the Tampa field office – but Pai says the Commission’s doing its best to address the pirate problem that is “a problem all across the East coast.” That when he says the staff is determined to be “cops on the beat” against unlicensed operators. That seemed to satisfy Bilirakis. More from the hearing – there’s support for a new minority tax certificate plan. It would incentivize an owner to sell to a qualified minority by offering a tax break or deferral. And we haven’t mentioned the #1 complaint around telecom – doing something to choke off robocalls and “spoof calls.”

Check out the full Tom Taylor Now newsletter which also includes questions posed to Chairman Pai, about defining Net Neutrality.

Operator shares what it’s like to work for a numbers station

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(Source: Numbers Stations)

Working at a numbers station 6 decades ago was not much different than working at an AM broadcast station. Located on a WWII old Naval Base it consisted of one building surrounded by a double chain link fence inside which older local men drove pickup trucks around for security. Inside the building there was a workshop, two 20,000-watt AM shortwave transmitters, crystal controlled oscillators, and a soundproof booth with a record player and records of well-known music in a language and culture common to the target. Outside the compound was an antenna farm with a log periodic antenna, a rhombic, and a couple dipoles.

I lived, with my wife, about a mile from the site and would drive through a back road to the location, be admitted by security through each gate, and park, and relieve the other op who, after briefing me, was free to go home. My job was to follow a schedule, select the proper frequency at the proper time, tune the transmitter, hit the plate voltage, play the record the schedule told me to, and then recite the messages arranged in five-number groups of numbers in the appropriate language into the microphone in the recording booth. This was all done live and, as far as I know, no recordings were kept.

[…]Other than that it’s just a job. The messages were all prepared somewhere else by someone else and delivered to us along with the schedule. We all had high level clearances but we never knew who we sent these to or what the real ones might have said. This sort of compartmentalization was (and is) common.

I often thought of those for whom the messages were intended… how they felt, where they were… whether they were in an attic or shed or stranded somewhere copying down a message that was a threat to their very lives on a radio that was a death penalty to simply be in possession of. I was very careful to do it right.[…]

Read the full article at Numbers-Stations.com.