Category Archives: Shortwave Radio

Radio Waves: New Quantum Receiver, Virus and Distance Learning by Radio, BBC Woofferton Early Days, and Hello Morse

Radio Waves: Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers. To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Andrea, Kim Andrew Elliott, Dave Porter, and Phillip Novak for the following tips:

New quantum receiver the first to detect entire radio frequency spectrum (Phys.org)

A new quantum sensor can analyze the full spectrum of radio frequency and real-world signals, unleashing new potentials for soldier communications, spectrum awareness and electronic warfare.

Army researchers built the quantum sensor, which can sample the radio-frequency spectrum—from zero frequency up to 20 GHz—and detect AM and FM radio, Bluetooth, Wi-Fi and other communication signals.

The Rydberg sensor uses laser beams to create highly-excited Rydberg atoms directly above a microwave circuit, to boost and hone in on the portion of the spectrum being measured. The Rydberg atoms are sensitive to the circuit’s voltage, enabling the device to be used as a sensitive probe for the wide range of signals in the RF spectrum.

“All previous demonstrations of Rydberg atomic sensors have only been able to sense small and specific regions of the RF spectrum, but our sensor now operates continuously over a wide frequency range for the first time,” said Dr. Kevin Cox, a researcher at the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, Army Research Laboratory. “This is a really important step toward proving that quantum sensors can provide a new, and dominant, set of capabilities for our Soldiers, who are operating in an increasingly complex electro-magnetic battlespace.”

The Rydberg spectrum analyzer has the potential to surpass fundamental limitations of traditional electronics in sensitivity, bandwidth and frequency range. Because of this, the lab’s Rydberg spectrum analyzer and other quantum sensors have the potential to unlock a new frontier of Army sensors for spectrum awareness, electronic warfare, sensing and communications—part of the Army’s modernization strategy.

“Devices that are based on quantum constituents are one of the Army’s top priorities to enable technical surprise in the competitive future battlespace,” said Army researcher Dr. David Meyer. “Quantum sensors in general, including the one demonstrated here, offer unparalleled sensitivity and accuracy to detect a wide range of mission-critical signals.”

The peer-reviewed journal Physical Review Applied published the researchers’ findings, Waveguide-coupled Rydberg spectrum analyzer from 0 to 20 GigaHerz, co-authored by Army researchers Drs. David Meyer, Paul Kunz, and Kevin Cox[…]

Virus and distance learning by radio (1937, 1946) (AE5X Blog)

Six to eight decades ago polio was one of the most feared diseases in the US. In 1952 alone, 60,000 children were infected, 3000 died and many more were paralyzed.
The most severe outbreaks were in 1937 and 1946. My father was a victim of the 1946 epidemic, suffering minor paralysis in one leg as a child.

In 1937, many schools around the country closed, as did public pools, movie theaters and parks. But the Chicago public school system took an innovative approach.

During that period, 80% of US households contained a radio. This allowed 325,000 children in grades 3-8 to continue their education at home via radio lessons aired by six Chicago radio stations (WENR, WLS, WIND, WJJD, WCFL, WGN) that donated time for the purpose.

Program schedules for each day were printed in the morning paper. Home with more than one radio & more than one child often set up radios in different rooms so that each child could hear the appropriate grade’s lesson.

This continued for one month…until schools reopened in late September of that year.

Curriculum was developed by teachers and monitored over the air by school officials. After each episode, a limited number of teachers were available for phone calls. A large number of the calls were from parents distressed that they could not clearly receive the broadcasts.[Continue reading…]

BBC Woofferton Early Days (Ludlow Heritage News) [PDF]

Very few structures are left in the Ludlow area which can be traced back to the Second World War. However, look five miles south of the town towards the rise of the hills and a tracery of masts can be seen. Go closer, and a large building can be found by the road to Orleton, surrounded now by a flock of satellite dishes, pointing upwards. The dishes are a sign of the recent past, but the large low building was made for the war-time radio station aimed at Germany.

This little history attempts to tell the story of the British Broadcasting Corporation’s transmitting station at Woofferton near Ludlow in Shropshire during the first years of its existence. When and why did the BBC appear in the Welsh border landscape with a vast array of masts and wires strung up in the air? The story begins in 1932, when the BBC Empire Service opened from the first station at Daventry in Northamptonshire. Originally, the service, to link the Empire by wireless, was intended to be transmitted on long-wave or low frequency. But, following the discovery by radio amateurs that long distance communication was possible by using high frequency or short waves, the plan was changed. Later in the decade, the BBC expanded the service by also broadcasting in foreign languages. Although Daventry had a distinguished name in the broadcasting world, it was never technically the best place for a short-wave site, being on a hill and close to a growing town.

This article can be found in the Ludlow Heritage News: click here to download the full PDF.

Hello Morse: A collection of AI and Chrome experiments inspired by Morse code on Android Gboard (Google)

Developer Tania Finlayson found her voice through Morse code. Now she’s partnering with Google to bring Morse code to Gboard, so others can try it for accessible communication.

Morse code for Gboard includes settings that allow users to customize the keyboard to their unique usage needs. It works in tandem with Android Accessibility features like Switch Access and Point Scan.

This provides access to Gboard’s AI driven predictions and suggestions, as well as an entry point to AI-powered products, like the Google Assistant.[…]

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“The Last Elephant Cage” is a fascinating NSA documentary about the monolithic FLR-9 antenna system

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Many thanks to SWLing Post contributor, Andrea Borgnino (IW0HK), who shares the following video–a 15 minute NSA documentary–about the FLR-9 “Elephant Cage” antenna in Anchorage, Alaska.

Click here to view on YouTube.

WRTH 2021: A look inside the 75th Anniversary Edition!

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Last week, I received a long-awaited Christmas gift: the 2021 World Radio TV Handbook. Normally, I’d receive this annual guide in the December time frame, but because of delays in international postal services due to the Covid-19 pandemic, I took delivery a few weeks late.

I always look forward to receiving this excellent staple radio reference guide–and this is their 75th edition! As I say each year, the WRTH has never disappointed, so my expectations are always quite high.

Once again, the WRTH lived up to my expectations.

WRTH’s team of noted DXers from around the world curate frequencies and broadcaster information by region; while I’m not sure how they orchestrate all of this, the end result is truly a symphony of radio information. In addition to broadcaster listings, WRTH’s radio reviews, feature articles, and annual HF report make for excellent reading.

But the WRTH isn’t just a frequency guide: the publication always devotes the first sixty or so pages to articles relating to various aspects of the radio hobby. Following, I offer a quick overview of these.

The first article always features a WRTH contributor: this year, they feature Stig Hartvig Nielson. His path to becoming a WRTH contributor began in his childhood when he said he was “tall enough to reach the radio tuning knob and tune away from dull Radio Denmark.” His love of radio lead him down the path of becoming a broadcaster. Many of us know him via his station, Radio208.

WRTH Reviews

The second set of articles is always my favorite: WRTH receiver reviews.

This year, WRTH begins with an in-depth review of the AOR AR5700D wideband communications receiver–a radio I’d likely never touch in real-life, so it’s wonderful to take such a deep dive. Next up is a review of the Bonito NTi MegaDipol MD300DX antenna which gets high marks for high gain, low noise, and good dynamic range. The following in-depth review is of the benchmark Icom IC-7610 general coverage transceiver. This was the first time I’ve read a review of this SDR transceiver with radio listeners in mind. WRTH then review the Bonito NTi CCMC30 common mode noise filter–a tool that can help radio enthusiasts mitigate RFI.

A review of the SDRplay RSPdx follows and the review speaks to the performance improvements included with the new HDR mode. The next review is actually one I authored of the Tecsun PL-990 portable radio–it’s always an honor to be in the pages of the WRTH!

The final review is of the Valent F(x) KiwiSDR; a little web-connected SDR receiver that has certainly transformed the nature and accessibility of remote listening.

WRTH Features

The first feature article, written by none other than Dave Porter, focuses on the development of HF broadcast transmitters. This article adds to the one he authored last year which focused on broadcast antennas. Dave is amazing because he has such an extensive history in the world of HF broadcasting and his experience and expertise are obvious in all of his writing. This is a must-read for those who want to know more about the “business side” of an international broadcast signal!

Manfred Rippich’s feature, Radio in Bhutan, explores the story of broadcasting in one of the most mountainous countries in the world where communities–including the capitol–are not easily accessible. Radio broadcasting plays an important role in this amazing country.

The following feature, Coastwatchers & the AWA Teleradio 3BZ written by Dr Martin Hadlow, takes a look at the importance of portable radios in the Pacific War. An absolutely fascinating piece for those of us who love radio history.

The final feature was written by Alan Pennington and explores the dynamic Scandinavian Weekend Radio. It’s hard to believe SWR has celebrated 20 years on the air as of 2020. Pennington’s article explores the grassroots energy of this unique broadcaster!

The final article–a tradition–is the WRTH HF propagation report/forecast by Ulf-Peter Hoppe. Always an informative read especially as we continue to work our way out of a long-term solar slump.

The 75th is another fantastic edition of the World Radio TV Handbook. As I say every year, I’ve never been disappointed with WRTH. Their publishing standards are such that the quality of their reviews, their writing, and (most importantly) their broadcast listings are simply unparalleled.

For DXers who collect QSL cards, you’ll find that broadcaster contact information in WRTH is often more up-to-date than a broadcaster’s own website. When readers contact me asking for QSL information from an obscure broadcaster, the first place I search is the current WRTH. Remember: their information is based on volunteer contributors who specialize in specific regions of the world–the most knowledgeable regional DXers keep this publication accurate.

Purchase your copy of WRTH 2020 directly from WRTH’s publishers, or from a distributor like Universal Radio (US) , Amazon.com (US), or the Book Depository (international).

Photos of Mr Liang of Tecsun radios

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Many thanks to SWLing Post contributor, Mei Tao, who shares the following photos of Tecsun’s chairman, Mr. Wei Liang:

Thanks for sharing these photos, Mei Tao. It’s evident that Mr. Liang is a proper radio enthusiast–he’s certainly a major innovator in the world of shortwave radio portables!

An update from Radio Kahuzi

Rob compares horizontal and vertical SWL random wire antennas

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Many thanks to SWLing Post contributor, Rob Zingarelli, who shares the following guest post that originally appeared on his blog in October, 2020:

Shortwave Antenna: Vertical or Horizontal?

by Rob Zingarelli

This is a question that has circled around on the fringes of my consciousness for years now, but one that I’ve never quite found time to test. And it is a simple question: When using a random wire antenna with a portable shortwave receiver, is it better to string the wire vertically or horizontally, or does it even matter? Mostly this is a question when out camping, because arranging a 19′ wire vertically is usually a good bit more involved than just stringing it out along some nearby bushes.

Before going any farther, I want to point out that this is an exercise in ordinary backyard shortwave listening with relatively inexpensive equipment. There are many, many better-engineered and more costly solutions to the technical challenge of shortwave scanning, and this does not address any of those sophisticated approaches. This is for the person who opens up the box and wonders about the best way to hang the included long-wire auxiliary antenna.

Equipment: Tecsun PL-660 SW/AM/FM/Air Band receiver, with its included 19′ random-wire antenna. Internal battery power used.

Conditions & Time: Clear local weather. hamqsl.com’s nowcast of band conditions were fair from 3.5-14.35 MHz, and poor for higher frequencies, with SFI = 72, SN = 26, A = 5, K = 1. Time was 21:00-21:30 UTC, or 4-4:30 pm local CDT.

Procedure: Out in the backyard (typical residential neighborhood, well-spaced ~150′ between houses, above-ground power lines 125′ away), suspend random wire from ground to its full length. This was achieved using a length of paracord over a tree limb, with the tree trunk ~30′ from the radio’s location. With the PL-660’s antenna gain control set to “Normal” (i.e., the mid-setting of Local-Normal-DX) and the bandwidth set to narrow, use the receiver’s automatic scan function to see how many stations were received. Make notes of the number of transmissions detected, reception characteristics and quality, and any perceived noise levels. Re-orient the antenna to a low horizontal position, over two sawhorses approximately 3′ high (see picture), and repeat.

Sawhorses spaced ~17′ apart. Radio and notepad can be seen on ground in front of the near sawhorse.

Results: For the vertical antenna orientation, 32 stations were detected between 5959 – 15730 kHz. Nearly all were intelligible, with those at the lower end more steady and those a the higher end much more variable in strength. For the horizontal antenna orientation, 21 stations were detected between 9265 – 1570 kHz. Similar overall signal quality was heard for the received stations in either antenna orientation. More noise was noticeable at the lower frequencies between the stations for the vertical antenna orientation. However, this was significantly below the received signal levels, and not an issue in the overall listening quality.

Conclusions & Discussion: Suspending the wire antenna vertically worked better, especially at the lower frequencies. Getting a wire up 21’+ vertically is usually not as convenient as stringing it horizontally, but it may be worth the extra effort, depending on the location, campsite, nearby trees, etc. The overall conditions were typical for fall camping weather, with fair-to poor radio propagation conditions, so this result should be broadly applicable for how SW portables are often used. This result may change with propagation and radio noise conditions, both for atmospheric and local noise sources. Testing will continue as propagation conditions improve with solar cycle 25 getting underway.

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Addendum, 10/12/20: While writing this up yesterday evening, it occurred to me that I hadn’t tested the PL-660’s built-in whip antenna. This comparison is important, because sometimes the wire antenna is too cumbersome to deploy. So, how does the whip antenna compare?

Conditions & Time: Overall, very similar to yesterday. hamqsl.com reports fair conditions from 3.5–14.35 MHz, and poor for higher frequencies. SFI = 72, SN = 26, A = 3, K = 1. Same time of day as yesterday’s testing.

Procedure: Repeat of yesterday, with the whip antenna added to the test. The whip was oriented vertically.

Results: For the vertical 19′ wire, 31 stations were found by the auto-scan function between 2380 – 15770 kHZ. Electrical noise was low but audible in the 3 MHz region, fading to none at higher frequencies, and not a significant source of interference with any stations. For the horizontal wire, 15 stations were found between 9265 – 13630 kHz. Electrical noise was barely audible. With the whip in use only 1 station was found. Switching the antenna gain to its DX (most sensitive) setting, 6 stations were found.

Revised Conclusions: Adding to yesterday’s conclusions, the whip antenna functioned but was vastly inferior to the wire antenna in either configuration, even with the gain set to DX. Today’s results with the wire antenna were, unsurprisingly, very similar to yesterday’s, given that the ionospheric and weather conditions were nearly identical. Noise was not a factor in receiving for any of these antennas or configurations, but did noticeably increase for the vertical wire antenna.

Thank you for sharing this, Rob! It’s experiments like this that help us determine, especially, what antenna setups work at our own particular locations since RFI characteristics can vary so much. I’m guessing had your horizontal wire been elevated to even 20′ off the ground it might have produced better results, but sometimes this can be difficult to achieve. I like how you used the auto search function to determine the number of stations you could receive with each setup and it was a great addition to include the built-in telescoping whip.

Thank you again for sharing your results with us!

“Voice of America Marks 79th Anniversary”

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(Source: VOA News)

Voice of America is 79 years old today [February 1, 2021].

Its 1942 debut was unpretentious — a live, 15-minute shortwave radio broadcast transmitted into Germany from a small studio in New York City.

Now, the U.S.-funded but independent VOA reaches more than 280 million people across the globe each week in more than 40 languages.

Its stories, covering the range of the human existence in the Unites States and countries throughout the world, appear on digital, television and radio platforms and can be accessed on mobile phones and social media. VOA stories are carried on a network of more than 2,500 affiliate stations.

In the first broadcast in 1942, a little more than seven weeks after the United States officially entered World War II, listeners first heard an American patriotic song, “The Battle Hymn of the Republic.”

Then, announcer William Harlan Hale said, “We bring you Voices from America. Today, and daily from now on, we shall speak to you about America and the war. The news may be good for us. The news may be bad. But we shall tell you the truth.”

It is a credo that since 1976 is embedded in the VOA Charter, which by law requires the organization to “serve as a consistently reliable and authoritative source of news.” It says VOA news must “be accurate, objective and comprehensive.”

VOA is part of the U.S. Agency for Global Media, the government agency that oversees all non-military, U.S. international broadcasting.

VOA’s professional journalists produce dozens of stories every day without interference from the U.S. government.