Category Archives: DRM

DRM Test Broadcast on 954 kHz in the Czech Republic

DRM Test Broadcast on 954 kHz from Transmitter in Czech Republic (DRM Consortium)

DRM is now on air in the Czech Republic, on a medium wave channel that used to carry a powerful AM signal. It is broadcast on 954kHz (power reported as 3kW) from the ?eské Bud?jovice transmitter site, located in the South Bohemian region re-using the old AM antenna with a modulator connected to the existing 30 kW AM transmitter.

The DRM transmission on 954kHz was even received in the country using a KiwiSDR.

This is a trial of DRM within the Czech Republic and is scheduled to come to an end possibly in the second half of 2023. The content is supplied by Radiožurnal, a news and journalism station that broadcasts 24 hours a day covering events at home and abroad. The station also carries music in between the news segments.

One of the listeners receiving the DRM signal in the country reported: “From my listening on the remote receivers, it seems to me that a few low-powered AM transmitters could cover the whole country”. [Click here to read the original article…]

Spread the radio love

DXERS Diary via KTWR DRM

Many thanks to SWLing Post contributor, Arun Kumar Narasimhan, who shares the following announcement:

My Name is Arun Kumar Narasimhan from Chennai in India in India and I have been producing and presenting “DXERS DIARY”, a 5-minute weekly DX programme in KTWR’s DRM broadcast in 15205 kHz from 15.00 hrs UTC every Sunday from January 3, 2021.

DXERS Diary DX Programme is also being broadcast every Wednesday in 11965 kHz from 11.01 hrs UTC to 11.07 hrs UTC as part of KTWR’s South East Asia block. You can also listen in 9965 kHz from 14.30 hrs UTC every Wednesday. Those who can’t tune in to DRM can now listen to the program in Shortwave.

This programme is designed to make it easy for listeners to contribute to the advancement of the DX hobby. In this programme, we broadcast listeners’ logs, band scans, sent to us from listeners across the world, information about sunspot number, SFI forecast and A-index , news and frequency changes by various radio stations around the world.

Listeners can send their band scans, shortwave radio logs, reception reports, views and opinion about the programme to “[email protected]”.

Spread the radio love

Radio Waves: Antenna ID, DRM Receiver Requirements Revisited, BBC Broadcasting Technology, and Digital Sound Broadcasting Framework in Kenya

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


Identify that antenna by sight (Hackaday)

It’s a skill that radio amateurs pick up over years but which it sometimes comes as a surprise to find that is not shared by everyone, the ability to casually glance at an antenna on a mast or a rooftop and guess what it might be used for. By which of course I mean not some intuitive ability to mentally decode radio signals from thin air, but most of us can look at a given antenna and immediately glean a lot of information about its frequency and performance. Is this privileged knowledge handed down from the Elmers at the secret ceremony of conferring a radio amateur’s licence upon a baby ham? Not at all, in fact stick around, and I’ll share some of the tricks. [Continue reading…]

Minimum Receiver Requirement Document Revisited (DRM Consortium)

The latest version of the document (mrr.drm.org) describes the DRM (Digital Radio Mondiale) receiver characteristics for consumer equipment intended for terrestrial reception operating in the frequency bands below 30 MHz (i.e. DRM robustness modes A to D) and also those for the frequency bands above 30 MHz (i.e. DRM robustness mode E). The goals of the document are to: provide guidelines to receiver manufacturers for minimum receiver performance and technical features, to offer confidence to broadcasters that their DRM transmission can be received by all receivers in the market, to assist broadcasters to plan their network and to give full confidence to consumers that all important DRM features are supported by receivers and all DRM transmissions can be received when they acquire a digital DRM receiver.

Click here to download (PDF).

BBC broadcast tech: then and now (Engineering and Technology)

In its centenary year, we look at the BBC’s pivotal role in making the broadcast and radio technology field what it is today.

Daily London broadcasts by the newly formed British Broadcasting Company began from Marconi House on The Strand, on 14 November 1922, using the call sign 2LO, with transmissions from Birmingham and Manchester starting on the following day.

The first broadcast by the young company, which was heard as grainy, muffled speech, was read by Arthur Burrows, who joined the BBC as director of programmes. Notably, he was one of the first people to move from newspaper to broadcast reporting.

At the end of 1922, Scottish engineer John Reith, who was just 33 years old at the time, was appointed general manager of the BBC, which then had a staff of four. Reith is remembered for establishing the tradition of independent public service broadcasting in the United Kingdom.

Within months, the growing organisation moved into the same building as the Institution of Electrical Engineers at Savoy Hill (now the IET’s Savoy Place event venue), where it continued to expand. This was an obvious home for the young BBC, and for the next nine years this is where early innovations of broadcasting occurred.

The British Broadcasting Corporation, as it is known today, was established in January 1927 as a public corporation, and in 1934 it moved from Savoy Hill to the purpose-built Broadcasting House in Portland Place. [Continue reading…]

CA plans digital radio shift on shortage of frequencies (Business Daily Africa)

Kenyan broadcasters will be allowed to adopt a new digital radio standard, which will enable them to use their current spectrum to transmit their signals through a digital network, as the sector regulator moves to address the shortage of analogue frequencies.

The Communications Authority of Kenya (CA) has called for stakeholder and public views on a draft Digital Sound Broadcasting (DSB) framework it has formulated to ensure the efficient use of the available broadcasting spectrum and encourage investment in the sub-sector.

“The objective of this consultation is to develop a suitable framework for Digital Sound Broadcasting in Kenya to address the challenge of high demand and low availability for analogue FM broadcasting frequencies that is currently being experienced,” said the CA. [Continue reading…]


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

Reception Reports Requested: “One-Off” DRM Broadcast From Woofferton To India Today

Many thanks to SWLing Post contributor, Mangosman, who shares the following announcement from the DRM Consortium:

Encompass Plans A One-off Broadcast From Uk To India On Nov 4th

Encompass Digital Media will be running a one-off transmission from its site in Woofferton, UK, on Friday 4th of November. This electronic music broadcast will target the whole of India, around 5,000 miles (or about 8,000 kilometres) as the crow flies to the centre of the country. This might be the longest distance Encompass has covered with its DRM transmissions.

Before the actual broadcast, several tests were run using different frequencies, antennas and power combinations. The final test on November 2nd to confirm final set-up was a great success as the audio could be recorded from a KiwiSDR online receiver located in New Delhi. The SNR of 20dB was measured in New Delhi and 23.9dB in Bangalore, which proves the power of shortwave radio and how DRM and its excellent sound, even in shortwave, can travel such long distances. The audio was also decoded in Bangkok, and a listener report came even from Canada!

This experimental broadcast promoting the music of C. M. Obrecht is scheduled for tomorrow [today Nov 4 at time of publishing], 19:00 – 20:00 UTC, on 11710kHz. It will use xHE-AAC codec with DRM Mode B, transmitting at 125kW on a 78* bearing from Woofferton. The audio will be accompanied by ancillary data including a slideshow image of the album cover art.

Although the transmission time will mean it will be quite late in India, Encompass is interested in receiving any reception reports from within the country, particularly from anybody using a car radio. Please send reception reports to Steve Palmer at: [email protected] (This is also the address to use for further information about Encompass’ DRM projects and services).

Spread the radio love

Radio Waves: BBC Centenary, RNZ Continues DRM Investment, Hurrican Ian Help from a Ham, and Philips 353A Restoration,

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


BBC centenary marked at first national radio transmitter (BBC News)

The BBC’s 100th anniversary has been marked in the town that enabled it to make nationwide radio broadcasts.

Opening on 27 July 1925, the Daventry Transmitter was the world’s first long wave transmitting station.

Known as 5XX, it was on Borough Hill in the Northamptonshire town and its first transmission was with the a poem called “Daventry Calling…”.

Sophie Good from the town’s museum said: “Daventry has got a strong affiliation with the BBC.”

The BBC chose the position so the transmitter could cover the maximum land area.

It brought the total audience within listening distance to 94% of the population.

When it opened, the poem by Alfred Noyes was followed by speeches from the postmaster general, external and the mayor of Daventry, introduced by Lord Gainford, BBC Chairman.

The then Prime Minister Stanley Baldwin sent a message, published in the Radio Times, which said he saw “Daventry as another milestone on the road to the social betterment of our people”. [Continue read at the BBC…]

The BBC is celebrating its 100th birthday (NPR / AP)

LONDON — The British Broadcasting Corp. marked 100 years of broadcasting on Tuesday, a century after a group of wireless manufacturers founded the company and began filling the airwaves with its first daily radio service.

The BBC was founded on Oct. 18, 1922, in London and daily broadcasting began a month later. The broadcaster is marking its centenary with a series of special programs, including a guest appearance from King Charles III on The Repair Shop, a program featuring expert craftspeople restoring antiques.

Actress Jodie Whittaker will make her last appearance as the Time Lord on a special episode of Doctor Who on Sunday, before Ncuti Gatwa takes over the role. [Continue reading…]

DRM Member Ampegon Wins a New Shortwave Transmitter Contract with RNZ (DRM Consortium)

In September 2022, Ampegon Power Electronics AG and RNZ (New Zealand public broadcaster) signed a contract to supply a new TSW2100-V4 100 kW shortwave transmitter to New Zealand. The transmitter will broadcast the RNZ Pacific service to millions of people living across the Pacific with high reliability and energy efficiency: Ampegon wins a new Shortwave Transmitter Contract with RNZ – Ampegon.

Continue reading

Spread the radio love

Mark explores North Korean DRM broadcasts over shortwave

In the last issue of Radio Waves, we featured an article by Hans Johnson at Red Tech about DRM broadcasts originating in North Korea. This caused me to question exactly what these DRM broadcasts were (Voice of Korea?) and why they’ve chosen to use DRM as the mode. 

Of course, who really knows? North Korea isn’t public about any of their activities, so we rely on information from enthusiasts who have taken it upon themselves to investigate and confirm. Johnson assumed, “The most likely use [of DRM] would be as an audio feed to other stations and sites.” He used Radio New Zealand’s DRM service as an example, but I felt this to be unlikely with North Korea who doesn’t seem to use FM, MW, or shortwave relay sites in other parts of the world. 

Fortunately, our friend Mark Fahey is an expert on North Korean media, broadcasts, and propaganda. Mark is the author and curator of the dynamic Behind The Curtain project. 

I reached out to Mark via text message regarding North Korea’s use of DRM. Here’s what Mark shared with me earlier this week. This roughly follows the string of messages we exchanged.

Mark writes:

[October 3, 2022] I have been turning into the North Korean DRM today  on the new reported frequency in the [Red Tech] magazine: 6140kHz, though it’s not VOK, it’s a relay of 819kHz Pyongyang.

This service is called KCBS – Korean Central Broadcasting Service – it’s the main domestic service that is available on MW (a few FM outlets) and domestic SW across North Korea.

I will grab an audio ID off DRM for you at the top of the next hour – 0100 UTC. The DRM broadcast is only running one audio stream. It’s ACC audio 14.56kbps. As for purpose, maybe to feed the national AM relays, but also could be for North Korean ships, etc.

The other DRM frequency of 3205kHz is not on the air at the moment. I will check for it over the next 24hrs etc.

I just recorded the top of the hour. It was going in and out of DRM sync – I will send it now. I will grab a better sample tonight when there is a darkness path. The sun is well up in Pyongyang & Sydney at the moment (Noon Sydney – 10AM North Korea). Here is the Top Of The Hour ID from 10 minutes ago…

KCBS 6140 kHz (October 3, 2022)

I will record the station opening as well tomorrow morning – this domestic service also has an interval signal (the same tune as VOK–the first bars of “The Song (Hymn) of Kim Il Sung”). The opening is at 2000 UTC.

[October 4, 2022] OK here you go: both audio files (one from 6140kHz and the other from 3205kHz) are just from minutes ago as KCBS Pyongyang signed on. The signals go in and out of DRM lock here and this morning 3205kHz was the better–displayed at SNR at 13dB but still the DRM signal was breaking up.

Both DRM transmitters are running the same program: the main MW national service as heard on 819kHz in Pyongyang.

So I’m sure this DRM has nothing to do with the Voice Of Korea and is for domestic purposes.

I actually do not think it has anything to do with feeding remote transmitters as the DPRK has fibre and microwave links already in place for that purpose. I myself think it’s more likely intended for North Korean fishing vessels, navy, merchant shipping etc. But of course, nobody truly knows!

KCBS 3205 kHz (October 4, 2022)

KCBS 6140 kHz (October 4, 2022)

Thank you so much for your recordings and insight, Mark!

As I mentioned, Mark has a massive DPRK audio repository on his website Behind The Curtain. These are recordings you simply can’t find anywhere else, including hours of pristine Pyongyang FM recorded on a CC-Crane Witness Mark personally smuggled into Pyongyang.

In fact, the above photo is the CC Witness in Mark’s hand overlooking central Pyongyang.

Mark told me that the CC Witness was ideal–he used it on a number of content gathering trips to North Korea as it resembled an MP3 player or dictation recorder rather than a radio. Since it wasn’t suspected as being a radio recording device, it passed through the North Korean border each time without incident.

It’s an understatement to say that Mark took a number of risks to gather North Korean media from “Behind the Curtain.” Thank you, again, Mark, for sharing this info about DPRK DRM broadcasts.

Visit Behind the Curtain

Check out numerous recordings from North Korea in Mark’s archive.

Spread the radio love

Radio Waves: WRMI Damaged by Ian, VOK Podcast, and North Korea Increases DRM

Radio Waves:  Stories Making Waves in the World of Radio

Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!


Shortwave Station WRMI Damaged by Ian (Radio World)

The vast Okeechobee, Fla., antenna farm of privately-owned WRMI, which transmits programming to the world via shortwave radio, was hit hard by Hurricane Ian.

WRMI has 14 transmitters and 23 antenna systems. “We had winds up around 100 miles per hour, and that did a real number on our antenna field,” said Jeff White, general manager of WRMI.

“So far we have three antennas that are probably destroyed beyond repair: one to Europe, one to Africa and one to Central America and the South Pacific.”

As pressing as rebuilding these three antennas is for WRMI, “The biggest job we have at the moment is putting back up dozens of telephone poles that carry the transmission lines from the transmitter building to the antennas,” said White. [Continue read at Radio World…]

>>–Click here to donate to WRMI’s Hurricane Relief Fund.–<<

Voice of Korea programming available as a podcast

Many thanks to SWLing Post contributor, Alex, who notes that some of VOK’s language services are now available in podcast form. If you wish to hear some old school propaganda in high fidelity, this is a good way to do so: check it out on Castbox.

North Korea Doubles Digital Radio Output (Red Tech)

After years of experimentation, the famously secretive nation has switched on another DRM shortwave transmitter. The big question: Why?


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love