Category Archives: AM

AirSpy SDR#’s New Killer Feature: the Co-Channel Canceller

An example of an AirSpy SDR# software screen.

A version of AirSpy’s popular SDR# software, showing the dark mode interface introduced in 2019. SDR# is always evolving, and the latest new tool is the Co-Channel Canceller.

It’s easy to take for granted the magical math that happens in Software Defined Radio. Occasionally though a breakthrough occurs which really grabs our attention, thanks to the hard work and bright minds of the designers behind the receivers and the software.

On the software side, the first series of “wow” moments happened for me in 2007-2008 when Nico Palermo of Perseus SDR fame expanded the program’s alias-free bandwidth incrementally from a modest (but impressive for the time) 100 kHz all the way up to the current 1600 kHz coverage.

The top-end 1600 kHz bandwidth was a game changer which allowed medium wave DXers the opportunity to record IQ-WAV files of the entire band for later review, analysis, and DXing. It’s even more impressive considering this expansion was done without any additional hardware or receiver updates.

What did Nico charge Perseus owners for this incredibly useful expansion of spectrum and waterfall bandwidth? Nothing! The program with its much improved features continued freely available to previous and new Perseus SDR owners.

Now in 2020, Youssef Touil, AirSpy’s hardware and software developer, brings a “killer feature” to his own SDR program named SDR#, for the benefit of medium wave DXers: the Co-Channel Canceller. The cost for this innovative tool? Yep, it’s a free addition to SDR#.

What are the benefits of the Co-Channel Canceller? This question is best answered by listening to three examples published by Youssef on his Twitter feed.

Read the descriptions below and listen to the brief audio files. In each example the Co-Channel Canceller is turned on and off a few times:

Experimenting with the Co-Channel Canceller. Here, the plugin is cancelling 594 kHz and letting 596 kHz thru. It's workish, but still needs some polishing. Check the audio!#Airspy #sdrsharp https://t.co/h5TMo4OlQL pic.twitter.com/koMKqQR1tW

— prog (@lambdaprog) October 15, 2020

So, the Co-Channel Canceller can also reject the dominant carrier to some extent and unburry the DX signals. Interesting side effect.
Check the audio!#airspy #sdrsharp https://t.co/vqDAIsobGm pic.twitter.com/f1WrsXIs3b

— prog (@lambdaprog) October 15, 2020

Yep. Works also for broadband noise. #airspy #sdrsharp https://t.co/rjBTuk16Kg pic.twitter.com/mGp5I2vUjq

— prog (@lambdaprog) October 15, 2020

For the first example above, I suspect the 594 kHz station is Saudi Arabia’s Radio Riyadh, and the off-channel 596 kHz signal is Al Idaa Al-Watania from Morocco. It’s impressive that the 50 kw 596 station can be uncovered to any degree, as Radio Riyadh is a whopping 2000 kw!

In the AirSpy Groups.io forum, Youssef clearly illustrates the steps needed to initiate the Co-Channel Canceller. I’ve reproduced his screenshots below:

I’ve only just begun to explore the possibilities of the Co-Channel Canceller tool, but it holds promise of helping to reveal and identify hopelessly buried co-channel or adjacent channel stations. Not only does it work “live” in real time reception, it functions well with recorded IQ-WAV files too! Checkout the newest version of SDR# and give this new feature a try. I can imagine situations where this tool could be highly useful at times for the shortwave DXer also.

Thanks, Youssef, for this brilliant tool, which you’ve included free with the newest SDR# !

I encourage radio hobbyists to support AirSpy’s efforts to advance the state-of-the-art. The diminutive AirSpy HF+ Discovery receiver is not only a reasonably priced SDR to use with SDR#, it’s a top performer and a recipient of the World Radio TV Handbook’s Best Value SDR award for 2020.

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

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Using the Icom IC-705 to record a local AM broadcast station

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In my previous post, I mentioned how much I enjoy the built-in digital audio recorder in the new Icom IC-705. While I wouldn’t buy a QRP transceiver specifically for built-in audio recording–there are less expensive options out there–it is an incredibly useful feature in my world.

After publishing that post, I was reminded that Monday morning (October 12, 2020) I connected the IC-705 to my homebrew Noise-Cancelling Passive Loop antenna mounted indoors at my parents’ house.

My NCPL antenna

Their house is like so many others in that it is inundated with RFI (radio frequency interference). I find that the NCPL antenna does a fine job mitigating most of that noise on the mediumwave band when I position it so that the bulk of the interference is nulled.

Monday morning, I tuned the IC-705 to my favorite local AM station: WAIZ on 630 kHz.

Weekday mornings, Dave and his “Wacky Wake-Up Crew” always put me in the right mood. They’re incredibly goofy/corny and 100% original.

It’s extraordinarily rare these days to find a local radio station, with local talent, creating a local daily radio show. Almost all of their ads are local, too.

I made the following off-air recording for myself, but decided to upload it for others to enjoy. I’m not sure what the receiver audio EQ or bandwidth filter was set to when I recorded this. It’s not a demo of receiver performance, just a little radio fun.

Enjoy:

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Radio Waves: A “Calm” Solar Cycle 25, WWJ History, Czech Radio’s Digital-Only Future, and UK Ham Radio Exam Stats

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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 Ron, Mike, and the Southgate ARC for the following tips:

As Disasters Roil Earth, A New Sun Cycle Promises Calmer Weather — In Space (NPR)

Giant flares and eruptions from the sun can cause space weather, and stormy space weather can interfere with everything from satellites to the electrical grid to airplane communications. Now, though, there’s good news for people who monitor the phenomenon — the sun has passed from one of its 11-year activity cycles into another, and scientists predict that the new cycle should be just about as calm as the last.

That doesn’t mean, however, zero risk of extreme weather events. Even during the last, relatively weak solar cycle, drama on the sun triggered occasional weirdness on Earth like radio blackouts, disruptions in air traffic control, power outages — and even beautiful aurorae seen as far south as Alabama.

Over each solar cycle, the roiling sun moves from a relatively quiet period through a much more active one. Researchers monitor all this activity by keeping an eye on the number of sunspots, temporary dark patches on the sun’s surface. These spots are associated with solar activity like giant explosions that send light, energy, and solar material into space.

Counting of sunspots goes back centuries, and the list of numbered solar cycles tracked by scientists starts with one that began in 1755 and ended in 1766. On average, cycles last about 11 years.

Based on recent sunspot data, researchers can now say that so-called “Solar Cycle 24” came to an end in December of 2019. Solar Cycle 25 has officially begun, with the number of sun spots slowly but steadily increasing.[…]

WWJ in Detroit: A 2020 Centennial Station (Radio World)

Iconic AM station just celebrated the 100th anniversary of its first broadcast

It was shortly after World War I that Clarence Thompson, a partner of Lee de Forest, formed a new company Radio News & Music Inc. in New York. His goal was to encourage newspapers to broadcast their news reports by wireless, using de Forest transmitters.

The franchise offer — available to only one newspaper in each city — offered the rental of a de Forest 50-watt transmitter and accessories for $750. Just one newspaper signed up for the deal; it was the Detroit News, led by publisher William E. Scripps.

He had been interested in wireless since investing in Detroit experimenter Thomas E. Clark’s wireless company in 1904. Scripp’s son, William J. “Little Bill,” was an active ham radio operator, operating a station in the Scripps home.

People Might Laugh

Scripp proposed accepting the Radio News & Music offer and building a Detroit News radio station in 1919, but he met resistance from his board of directors. It was not until March of 1920 that he was given the go-ahead to sign a contract.

The de Forest transmitter was shipped to Detroit on May 28, 1920, but was lost in transit; a second transmitter was constructed and sent on July 15. This delayed the installation of the station until August.[…]

Czech Radio has expanded DAB + coverage to 95 percent of the population and announced the switch-off of medium waves (Digitalni Radio)

NOTE: This is a machine translation of the original post in Czech.

Czech Radio has entered another, important phase of radio digitization. To date, the ?Ro DAB + multiplex signal has reached 95% population coverage. Ten new transmitters were launched in Bohemia and Moravia. You can find a detailed description of them below.

DAB + technology is becoming a common distribution channel for Czech Radio, which will be placed on the same level as analogue FM / FM broadcasting. All marketing activities will already include the “DAB + More Radio” logo. ?eské Radiokomunikace is planning to start certification of receivers next year in order to protect customers and facilitate orientation in the range for them and retailers.

According to the CEO of Czech Radio, René Zavoral, the public service media is proceeding in accordance with a long-term strategic plan. The head of communication and press spokesman Ji?í Hošna describes the step as a turning point that can affect the direction of the entire radio market.[…]

UK amateur radio exam report released (Southgate ARC)

The RSGB Examinations Standards Committee (ESC) report covering 2019 is now available for anyone to download

The report contains statistics for the both the RSGB amateur radio exams and the Air Cadets Organisation (ACO) exam which Ofcom considers to be equivalent to the RSGB Foundation.

Ofcom has been concerned about the participation of women in amateur radio and STEM disciplines. They requested the ESC to publish figures for the number of women taking the exams. Unfortunately the results are disappointing with only 9.9% of all exams being taken by women.

Download the ESC report from
https://rsgb.org/main/blog/examination-standards-committee-reports/2020/09/18/examinations-standards-committee-report-2020-for-activities-during-2019/

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Sangean SR-36: Paul discovers the basic AM/FM DSP receiver

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

This seems to be a new basic radio from Sangean:

Click here to view on Amazon (affiliate link supports the SWLing Post)

I’m not sure a radio could get more basic than this one: AA batteries, one volume control, one tuning control, built-in speaker, and a headphones jack.

Thanks for sharing, Paul!

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New DRM portables announced at IBC 2020

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Many thanks to SWLing Post contributor, Ed, who writes:

SWLing Post readers might be interested in reading the Digital Radio Mondiale Newsletter of September 2020, which covers DRM developments announced at IBC 2020.

These include DRM transmitter developments and deployments, and lots of new DRM receivers–such as eight (8) AM/FM/DRM portables, (1) AM/FM/SW/DRM portable, an automotive AM/FM/DRM model, a low-cost automotive AM/FM/SW/DRM model, and an AM/FM/SW/DRM development module with “High quality Tuner Frontend and Audio DAC” from Starwaves in Germany.

URL for newsletter: https://us10.admin.mailchimp.com/campaigns/show?id=5196729

URL for PDF describing new DRM receivers: https://www.drm.org/wp-content/uploads/2020/09/[email protected]

Thank you for the tip, Ed!

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QTC Article: Clear Channel MW Broadcast Stations in Australia

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Many thanks to SWLing Post contributor, Kris Partridge, who notes that the July/August 2020 issue of the Australian amateur radio magazine QTC (an issue we noted in a previous post is free) actually has an article about the mediumwave scene in Australia.

Click here to download a PDF of those pages only from the magazine, or better yet, grab the full issue from our previous post.

Thanks for pointing out this article, Kris. I really enjoyed reading this issue of QTC. Great to see a ham radio publication that covers more than *just* ham radio!

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Radio Waves: BBC radio reporters axed, Ham Radio on BBC Surrey, K6UDA on IC-705 features, and VLF balloon launched with request for detailed reception report

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Radio Waves: Stories Making Waves in the World of Radio

Many thanks to SWLing Post contributors Mark Hist, Kris Partridge, John Palmer, and the Southgate ARC for the following tips:

Radio reporters to be axed by BBC and told to reapply for new roles (The Guardian)

Radio reporters to be axed by BBC and told to reapply for new roles
Critics fear end of an era because of plans to make audio journalists work across media platforms

BBC radio voices have described and defined modern British history. Live reports from inside a British bomber over Germany during the second world war, or with the British troops invading Iraq in 2003, or more recently from the frontline of the parent boycott of a Birmingham school over LGBT lessons have also shaped the news agenda.

But now the BBC plans to axe all its national radio reporters and ask them to reapply for a smaller number of jobs as television, radio and digital reporters, rather than as dedicated audio journalists. Many fear it is not just the end of their careers but the premature end of an era for the BBC.

“Radio reporting is a different job. Of course, you can do both, but a report designed for television starts from a completely different place. Radio is also more agile and also a lot less expensive,” said one experienced broadcast journalist. “I am pretty sure most of us will not be given new TV roles. It seems sad to lose all that specific radio expertise.”

Among the well-known voices likely to be affected are Hugh Sykes, Andrew Bomford – who has just completed a long feature on the child protection process for Radio 4’s PM show – and the award-winning and idiosyncratic Becky Milligan, as well as a wider team of expert correspondents.[…]

Amateur radio on BBC Radio Surrey (Southgate ARC)

RSGB report Board Director Stewart Bryant G3YSX and SOTA organiser Tim Price G4YBU were interviewed on BBC Radio Surrey on Friday, September 11

The interview starts just before 1:43:00 into the recording at
https://www.bbc.co.uk/sounds/play/p08pkykw

RSGB https://twitter.com/theRSGB

What is Amateur Radio?
http://www.essexham.co.uk/what-is-amateur-radio

Free UK amateur radio Online Training course
https://essexham.co.uk/train/foundation-online/

10 Things That Make The Icom IC 705 A Revolution in Ham Radio (K6UDA YouTube)

VLF Balloon with 210m long antenna launches Sept 12 (Southgate ARC)

A high-altitude balloon experiment, launched by Warsaw University of Technology, is planned to lift off September 12, carrying a VLF 210-m-long fully-airborne antenna system, transmitting on 14.2 kHz

14.2 kHz is the former frequency of the Babice Radio Station in Poland.

The project is delivering very important data for a doctoral dissertation – any and all feedback on the reception of the signal (reception location, SNR, bandwidth etc.) is extremely important; your help with the listening to the transmission would be invaluable!

The balloon will also be transmitting APRS on 144.800 MHz FM, callsign SP5AXL.

Full details at
https://alexander.n.se/grimetons-sister-station-shall-reappear-in-the-stratosphere/?lang=en

Kris also points out this article which provides more detail about the station and request for reception reports:

Invented for the first time in 2014, in 2020 it will finally be implemented – the idea of „restoring” the TRCN, but in the stratosphere, where there are no mechanical limitations at the height of the antennas, and the achieved range can be gigantic.

The launch of a stratospheric balloon from the Przasnysz-Sierakowo airport of the Warsaw University of Technology is planned for September 12, 2020, in order to perform atmospheric tests – measuring UV radiation, recording the cloudy surroundings with a high-speed camera and conducting an inductive experiment at 14.2 kHz using a special antenna system.

The inductive system uses a modified long-wave transmitter (A1 emission, unkeyed) from the GLACiER project of the Warsaw University of Technology, implemented as part of the IGLUNA – a Habitat in Ice programme (ESA_Lab / Swiss Space Center). The power of the transmitter, due to the emission limits for this type of inductive devices, shall not exceed a few watts. The antenna system is a centrally fed (35: 1) dipole with capacitive (Hertzian) elements and a vertical axial coil. The electrical length is between 400 and 500 m, with a total system length of 210 m. The antenna is equipped with metalized radar reflectors.

The entire balloon mission will use 144.8 MHz (as SP5AXL) and 868 MHz (as part of the LoVo system) for navigation. Flight information will be available in advance in NOTAM (EPWW).
Planned balloon launch (even if the sky is full of ‘lead’ clouds) at 12.00 UTC (14.00 CEST, local time). The 14.2kHz experiment will be switched on on the ground, with the antenna initially folded in harmony. The predicted total flight time is 3 hours – around 13.30-14.00 UTC / 15.30-16.00 CEST it is planned to reach the maximum altitude of 30 km above sea level.

Source: https://trcn.pl/do-stratosfery-to-the-stratosphere/

How can you help with the experiment? By recording as much as possible! Every parameter is valuable – from the spectrum / screenshot with the spectrum, to the EM field strengths, SNR and bandwidth, to the change of the EM field strength over time. The collected data can be sent to our e-mail address: [email protected]. On the day of launch, we plan to post updates on the launch, flight and the experiment itself via our Facebook page: facebook.com/radiostacjababice.
Stay tuned!