The clear and periodic pattern of fast radio bursts may originate from a distant neutron star.
Astronomers at MIT and universities across Canada and the United States have detected a strange and persistent radio signal from a far-off galaxy that appears to be flashing with surprising regularity.
The signal is classified as a fast radio burst, or FRB — an intensely strong burst of radio waves of unknown astrophysical origin, that typically lasts for a few milliseconds at most. However, this new signal persists for up to three seconds, about 1,000 times longer than the average FRB. Within this window, the team detected bursts of radio waves that repeat every 0.2 seconds in a clear periodic pattern, similar to a beating heart.
The researchers have labeled the signal FRB 20191221A, and it is currently the longest-lasting FRB, with the clearest periodic pattern, detected to date.
The source of the signal lies in a distant galaxy, several billion light-years from Earth. Exactly what that source might be remains a mystery, though astronomers suspect the signal could emanate from either a radio pulsar or a magnetar, both of which are types of neutron stars — extremely dense, rapidly spinning collapsed cores of giant stars.
“There are not many things in the universe that emit strictly periodic signals,” says Daniele Michilli, a postdoc in MIT’s Kavli Institute for Astrophysics and Space Research. “Examples that we know of in our own galaxy are radio pulsars and magnetars, which rotate and produce a beamed emission similar to a lighthouse. And we think this new signal could be a magnetar or pulsar on steroids.”
The team hopes to detect more periodic signals from this source, which could then be used as an astrophysical clock. For instance, the frequency of the bursts, and how they change as the source moves away from Earth, could be used to measure the rate at which the universe is expanding. [Continue reading…]
Transmission company CRA looks at possibility for reusing analog transmission facilities
Czech transmission services company ?eské Radiokomunikace (CRA) is testing the DRM medium-wave digital radio system on 954 kHz.
According to a tweet from Marcel Prochazka, director of legal and regulatory affairs for CRA, the transmissions are originating from ?eské Bud?jovice in South Bohemia and operating at a power of 3.16 kW from a 107-meter HAAT antenna. Continue reading →
Since September 2020, ABC Radio has been quietly trialing DRM technology in Victoria
The public-service Australian Broadcasting Corp. and its transmission contractor BAI Communications Transmission Network hosted a public demonstration of Digital Radio Mondiale broadcasts on June 29, 2022. ABC highlighted the use of DRM on both AM and FM in Wagaratta, Victoria.
According to the DRM Consortium, the demonstration was the culmination of almost two years of COVID-impacted work to assess the performance of DRM services in Australia’s VHF and medium-wave bands.
Previously, the Australian Amateur Radio Experimenters Group reported that AREG member Steve Adler (VK5SFA) had been monitoring “a very un-publicized Digital Radio Mondiale (DRM) trial” on 747 kHz from Wangaratta in August 2021.
The Australian Communications and Media Authority provided ABC with a license variation to conduct the DRM 30 trials from September 1, 2020, to August 31, 2022.
At the public demonstration, senior representatives from the public, commercial and community radio sectors, along with regulators and other interested parties, were able to hear and see the capabilities of DRM broadcasting on AM from Dockers Plains and on FM from Mount Baranduda. They were also able to review the transmission equipment at Wagaratta.[Continue reading…]
The James Webb Space Telescope probably needs no introduction, since it is perhaps the most important and well-known mission of the last years. It was launched on Christmas day from Kourou, French Guiana, into a direct transfer orbit to the Sun-Earth L2 Lagrange point. JWST uses S-band at 2270.5 MHz to transmit telemetry. The science data will be transmitted in K-band at 25.9 GHz, with a rate of up to 28 Mbps.
After launch, the first groundstation to pick the S-band signal from JWST was the 10 m antenna from the Italian Space Agency in Malindi, Kenya. This groundstation commanded the telemetry rate to increase from 1 kbps to 4 kbps. After this, the spacecraft’s footprint continued moving to the east, and it was tracked for a few hours by the DSN in Canberra. One of the things that Canberra did was to increase the telemetry rate to 40 kbps, which apparently is the maximum to be used in the mission.
As JWST moved away from Earth, its footprint started moving west. After Canberra, the spacecraft was tracked by Madrid. Edgar Kaiser DF2MZ, Iban Cardona EB3FRN and other amateur observers in Europe received the S-band telemetry signal. When Iban started receiving the signal, it was again using 4 kbps, but some time after, Madrid switched it to 40 kbps.
At 00:50 UTC on December 26, the spacecraft made its first correction burn, which lasted an impressive 65 minutes. Edgar caught this manoeuvre in the Doppler track.
Later on, between 7:30 and 11:30 UTC, I have been receiving the signal with one of the 6.1 metre dishes at Allen Telescope Array. The telemetry rate was 40 kbps and the spacecraft was presumably in lock with Goldstone, though it didn’t appear in DSN now. I will publish the recording in Zenodo as usual, but since the files are rather large I will probably reduce the sample rate, so publishing the files will take some time.
In the rest of this post I give a description of the telemetry of JWST and do a first look at the telemetry data. [Continue reading…]
The average person’s perception of a ham radio operator, assuming they even know what that means, is more than likely some graybeard huddled over the knobs of a war-surplus transmitter in the wee small hours of the morning. It’s a mental image that, admittedly, isn’t entirely off the mark in some cases. But it’s also a gross over-simplification, and a generalization that isn’t doing the hobby any favors when it comes to bringing in new blood.
In reality, a modern ham’s toolkit includes a wide array of technologies that are about as far away from your grandfather’s kit-built rig as could be — and there’s exciting new protocols and tools on the horizon. To ensure a bright future for amateur radio, these technologies need to be nurtured the word needs to be spread about what they can do. Along the way, we’ll also need to push back against stereotypes that can hinder younger operators from signing on.
On the forefront of these efforts is Amateur Radio Digital Communications (ARDC), a private foundation dedicated to supporting amateur radio and digital communication by providing grants to scholarships, educational programs, and promising open source technical projects. For this week’s Hack Chat, ARDC Executive Director Rosy Schechter (KJ7RYV) and Staff Lead John Hays (K7VE) dropped by to talk about the future of radio and digital communications. [Continue reading…]
Radio World reports the Electromagnetic Interference generated by Electric Vehicles is causing some EV automakers to drop AM (medium wave) radio
The article says:
Some EV automakers are dropping AM altogether due to audio quality concerns, but that’s just one piece of the puzzle as radio continues to fight for space on the dash.
“As carmakers increase electric vehicle offerings throughout their lineups, the availability of AM radio to consumers is declining,” said Pooja Nair, communications systems engineer with Xperi Corp., in a Radio World guest commentary. “This is because the effects of electromagnetic interference are more pronounced in EVs than in vehicles with internal-combustion engines.”
In other words, electromagnetic frequencies generated by EV motors occupy the same wavelength as AM radio signals. The competing signals clash, effectively cancelling each other out. As EV motors grow more powerful, AM static tends to increase.
Many thanks to SWLing Post contributor, Mangosman, who shares the following tip from Mike Sabin at KTWR via Alokesh Gupta’s blog:
Due to requests for later broadcasts, improved propagation, and the addition of a program, KTWR is changing its DRM broadcast schedule effective 3rd July, 2022.
KTWR Digital Broadcasts
DRM broadcasts (Effective 3rd July 2022):
Day Time(UTC) Frequency Coverage Area Language
Saturday 1100-1127 12000 kHz China English
Saturday 1128-1230 9910 kHz Japan Japanese, English
Mon-Fri 1215-1245 9910 kHz China Mandarin
Sunday 1500-1545 15205 kHz India English
Sunday 1600-1630 15390 kHz India South Indian languages
It shows the unit tuned to 6095khz and later to 13810khz, with music being played, I assume via the converter and transmitted on a free FM frequency the car radio is tuned to.
The video also shows a couple of shots of the converter and remote control, and a second bit of hardware that I’m unsure of its function. This was all back in 2007, I gather. The comments from those that have seen the video are not I suspect from people familiar with SW listening, and the suspicion that a car whip antenna is entirely unsuited to SW reception should be questioned, as I had personal experience of this while in Saudi Arabia in 1990, where SW car radios were not uncommon, and strong signals provided perfectly acceptable audio quality. Sure, 1 metre long whip won’t be much good for SW DX, but who’s going to be doing that while driving a car?
Anyway, I’m curious to know if anyone has ever purchased a Starwaves Truckbox? I gather it is currently not available.
Jerome van der Linden
Thanks for sharing this, Jerome. I, too, am curious if the Starwaves Truckbox made it beyond the prototype stage to be mass produced. Please comment if you have more info!
Many thanks to SWLing Post contributor, Paul Jamet, who writes:
Several listeners have posted videos on YouTube about receiving broadcasts of “The Voice of Korea” on 6140 kHz DRM – Digital Radio Mondiale.
One video in particular caught my attention, from Indian listeners in the Kerala region:
Indeed, these headphones use a Chinese receiver, the G-226 from GOSPELL which is also sold by TECSUN in Australia: https://www.tecsunradios.com.au/store/product/tecsun-drm-radio/
So, you can see how this receiver works.
All this has aroused my curiosity! And yesterday, Friday 17 June 2022, at 20:00 UTC I connected to several kiwi SDRs in the Pacific area. The DRKP signal could be picked up almost 8,000 km from the transmitter site near Pyong-Yang.
Here attached a screenshot and an audio file recorded with a kiwi SDR located a few kilometres away near Perth, Australia – Distance according to Google Maps, about 7960 km
The signal is encoded in AAC and not xHE AAC
[Audio: Note that the audio level jumps several times, so don’t turn up the volume too high.]
Who is this program for? According to Indian radio listeners, probably to the North Korean fleet in the Pacific. To be continued.
Have a nice weekend. Yours sincerely
I would have never guessed VOK would broadcast in DRM. Very interesting indeed. Perhaps we’ll learn more about this with time or someone can confirm whether or not this is actually VOK. Thank you for sharing this, Paul!
Connected to a Kiwi SDR installed in Portugal, I listened to this experimental station on its 15785 kHz DRM frequency and sent a listening report (in the form of an audio recording and a screenshot) to the Fraunhofer Institute in Erlangen, Germany: [email protected]
I received a nice QSL!
The signal was picked up as far as New Zealand one told me. I think reception reports from all over the world would be very much appreciated …
That’s brilliant, Paul. Thank you so much for sharing the recording and QSL info. Hopefully, they’ll continue to receive reports from across the globe. It might be fun, in fact, to see just how far one could DX this DRM broadcast via the KiwiSDR network. Frankly, good copy of Funklust’s 250W DRM signal in Portugal is pretty impressive!
Lysychansk (Ukraine) (AFP) – The portable radio in the dark cellar of the rocket-damaged kindergarten was transmitting news in Russian over whistling airwaves about the Kremlin’s military triumphs in Ukraine.
The six frightened women and lone man cowering in the heart of the east Ukrainian war zone had no idea whether to believe the monotone voice — or who was actually patrolling the streets of the besieged city of Lysychansk above their heads.
All they knew was that their building was hit a few days earlier by a Grad volley that left the tail end of one of the unexploded rockets sticking out of the pavement at a sharp angle just steps from the back door.
Their feverish fears vacillated between the idea that their shelter’s lone entrance might get blocked by falling debris and that the Kremlin’s forces might come knocking unannounced.
“The Russians on the radio just said that they have captured Bakhmut. Is that true?” Natalia Georgiyevna anxiously asked about a city 30 miles (50 kilometres) to the southwest that remains under full Ukrainian control. [Continue reading…]
In this guest commentary, DRM’s Ruxandra Obreja dives back in to the shortwave debate
Radio World’s “Guest Commentaries” section provides a platform for industry thought leaders and other readers to share their perspective on radio news, technological trends and more. If you’d like to contribute a commentary, or reply to an already published piece, send a submission to [email protected]
Below is perspective from Ruxandra Obreja, consortium chairman of Digital Radio Mondiale (DRM), in response to the commentary “Shortwave Revival a Non-Starter? The Authors Respond.” Her commentaries appear regularly at radioworld.com.
Seldom have we seen so much passion and polarizing views as in the recent articles for and against shortwave. From “it’s dead and gone” to “this is the revival,” all shades of opinion concerning this simple and all-encompassing platform have been expressed vigorously.
Shortwave Has a Pedigree
Shortwave, currently used for large-area, regional and international coverage in the developing world, certainly registered a decline in the past two decades (but it never died, as you can see here). This loss of pre-eminence in the developed world after the Cold War is not surprising. The platforms available nowadays, in the so called “global village,” include “basic” internet connections (browsing, emails, messaging apps of any type), to the prolific social media products (Facebook, Instagram, Twitter, Reddit), as well as video, radio and TV apps, satellites, mobiles give the impression that the whole world is truly connected!
At least this is the view from Washington, London, or Berlin. But there are the same proportion of people in Europe and America with everyday internet access as there are in Africa with no way to access to it. In such regions, shortwave and mediumwave radio remains essential for many, one of only a few reliable means to receive communication.
Since the arrival of AM and FM some seventy years ago, the invention of at least three largely recognized digital broadcasting systems (DRM, DAB/DAB+ and HD) is the most notable radio development. Digital Radio Mondiale — the DRM open-source global standard — is the latest and most advanced of the three systems, but the only one that can digitize radio in all frequency bands and the only digital option for shortwave.
Closing shortwave transmitters and then trying to restart them presents a huge time, effort and financial challenge. However, nowadays, broadcasters can often buy shortwave transmission hours, in digital, too, from third party distributors, and do not necessarily need to rebuild a comprehensive infrastructure. [Continue reading at Radio World…]
The closure of the public media organisation’s bureau demonstrates further curtailment of independent and free press in Russia.
CBC/Radio-Canada – the only Canadian news organisation with a permanent presence in Russia – has been ordered by the Kremlin to close its bureau. After more than 44 years of reporting from Moscow, CBC/Radio-Canada staff have been told to leave the country. However, Vladimir Proskuryakov, deputy chief of mission of the Russian Embassy to Canada, said they would not be rushed out of the country. He told the CBC News the staff would not be forced to leave in “less than three weeks.”
CBC/Radio-Canada currently has 10 employees working in Moscow, including locally hired staff.
BUDAPEST, Hungary (AP) — Intellectuals, broadcasters and cultural figures from Hungary’s Roma community are using the airwaves to reframe narratives and elevate the voices of the country’s largest minority group.
Radio Dikh — a Romani word that means “to see” — has broadcast since January on FM radio in Hungary’s capital, Budapest. Its 11 programs focus on Roma music, culture and the issues faced by their community, and aim to recast the way the often disadvantaged minority group is perceived by broader society.
“Roma people in general don’t have enough representation in mainstream media … and even if they do, it’s oftentimes not showing the right picture or the picture that is true to the Roma community,” said Bettina Pocsai, co-host of a show that focuses on social issues.
Radio Dikh, she said, aims to “give voice to Roma people and make sure that our voice is also present in the media and that it shows a picture that we are satisfied with.”
Some estimates suggest that Roma in Hungary number nearly 1 million, or around 10% of the population. Like their counterparts throughout Europe, many of Hungary’s Roma are often the subjects of social and economic exclusion, and face discrimination, segregation and poverty.
Adding to their marginalization are stereotypes about Roma roles in society, where they are often associated with their traditional occupations as musicians, dancers, traders and craftspeople that go back centuries. [Continue reading…]