Category Archives: DRM

Radio Marti now on DRM: Seeking your listener reports!

Many thanks to Edward R. Murrow Transmitting Station Chief Engineer, Macon Dail, who shareds the following announcement regarding their Radio Marti broadcasts:

We just powered up our 50 kW transmitter using DRM.

We are on a frequency of 7345 kHz and will be on daily from 1700-0200 UTC. We would love hearing from anyone that is able to copy and decode our transmissions.

The broadcast contain two audio programs.

Post Readers: If you successfully receive and decode a Radio Marti DRM broadcast, please send your detailed listener report to:  gstraub@usagm.gov This is certainly a unique opportunity to log a North American DRM broadcast!

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AM Revitalization: DRM Consortium asks FCC to adopt DRM

Many thanks to SWLing Post contributor, Alan, who shares this editorial from Radio World that features edited comments filed with the FCC by the DRM Consortium.

The following unedited letter was taken directly from the FCC comments database:

(Source: FCC Filing [PDF])

In your document (FCC19-123) you rightly highlight the great advantage of AM broadcasts, primarily the ability to cover large areas and number of listeners, while the band itself is losing popularity because of a variety of issues to do with propagation, interference, environmental changes. At the same time, digital audio broadcasting is no longer the new platform it was in 2002. At that time FCC mandated a proprietary system (IBOC, “HD radio”) as the only system to be used in the USA with the possibility of applying DRM for HF.

Since then DRM (the ITU recommended, only digital audio broadcasting for all bands, open standard, has been tested and used all over the world on all bands, short wave, medium wave and FM).

So while you are recommending now pure digital HD, based on the NAB tests and WWFD not completely convincing trial, we would urge the FCC to consider opening the straightjacket of 2002 and allow DRM to be used as a sure, tested, efficient way of digitizing the AM band.

There are several reasons for this:

DRM digital radio delivers in the AM bands significant benefits:

    • Audio quality that is on par or better than FM. DRM of all recognized digital
      standards is the only one using the ultra-efficient and compressed xHE-AAC audio
      codec that delivers at even very low bit-rates exceptional audio quality for speech
      but music, as well. (https://www.drm.org/listen-compare/)
    • Record Data: DRM has been tested in medium wave all over the world in both
      simulcast and pure digital. A list of the main tests (some of which have become ITU
      adopted documents) are included in Annex 4 of the DRM Handbook:
      https://www.drm.org/wp-content/uploads/2019/02/DRM-Handbook.pdf
      At the moment, 35 MW transmitters are on air in simulcast or pure DRM in India.
      http://prasarbharati.gov.in/R&D/
    • Auxiliary Data. DRM is the newest, most complete, open standard for digitizing radio in
      all frequency bands, and is recommended by ITU. DRM has been devised as a direct
      heir to analog AM (SW, MW). It uses 9/10, 18/20 kHz bandwidth and has a useful content
      bit rate of up to 72kbps. It carries up to 3 programs on one frequency and one data channel, while data can be carried on each of the audio channels as well. One of the great advantages of DRM is that alongside excellent audio, the receiver screens will display visual information of any kind required (albums’ titles, singers’ photos, maps, visuals of any sort, data of any kind). The Journaline application allows for extra information from the internet or the RSS feeds of the broadcaster to be captured and displayed. Currently broadcasters like the BBC, All India Radio, KTWR in Guam are using this extra facility that clearly differentiates digital form analog as a superior option.
    • Power/energy efficiency. Using SW or MW in DRM can reduce the power used up
      to 80%). As per calculations made by Ampegon, a medium wave transmitter can
      cover an area of 235000 sq km with a 100kW transmitter. The DRM EPR of such a
      transmitter is about 50kW and the coverage area is the same, while instead of one
      analog programme up to three digital channels and one data channel can be
      broadcast, all in excellent audio quality.
    • Spectrum efficiency (more programmes can be broadcast on one single frequency
      used for one programme in analog) as explained above.
    • DRM, unlike analog, offers enhanced and stable audio quality that is FM-like
      (mono or stereo). DRM also offers multiservice data enabled by applications like
      Journaline (the enhanced text services, more information captured as RSS feeds or
      form other internet source), slideshows, multilingual text (practically being able to
      show any characters of any language not just Latin script), and the Emergency
      Warning Functionality (EWF) in case of disasters.
    • Interference. This has not been noted as the DRM signal will always be lower than
      the analog one. AIR has not noted any interference in its operation of DRM
      transmitters. The mask values required for an optimal functioning of DRM
      transmitters is clearly stipulated in the ITU documents and as long as the network
      planning is correct, and the mask is respected there should not be any issue of
      interference in digital-analog or digital-digital DRM transmissions.
    • Receivers. Currently there are several receiver models and SDR options for the
      reception of DRM in AM. India has almost 2 million new cars fitted with DRM
      receivers, at no cost to the buyers, that are capable of and are receiving DRM
      mediumwave signals. The audio quality is excellent and a sure benefit to the users.
    • DRM is in direct succession to the analog AM (and FM) services, not owned or
      controlled by any single company and immediately available with full know-how and
      technology access by the transmitter and receiver industry.
    • As HD in mediumwave is a bit of a necessary step but still a leap in the dark, it
      would make sense from the practical aspects and even receiver solution availability
      to allow DRM as the best, clearly proven solution of digitizing the AM band (in
      preference or alongside HD) in the US.

In short, the salient advantages of DRM are:

    1. The audio quality offered by DRM is equally excellent on all the transmission bands:
      MW, SW or VHF
    2. Robust signal unaffected by noise, fading or other forms and interference in all bands
    3. Clear and powerful sound quality with facility for stereo and 5.1 surround
    4. More audio content and choice: Up to two and even three audio programmes and one
      data channel on one frequency
    5. Extra multimedia content: Digital radio listeners can get multimedia content
      including audio, text, images and in future even small-scale video, such as:

      • Text messages in multiple languages
      • Journaline – advanced text-based information service supporting all classes of
        receivers, providing anytime-news for quick look-up on the receiver’s screen;
        interactivity and geo-awareness allowing targeted advertising
      • Electronic Programme Guide (EPG), showing what’s up now and next; search
        for programmes and schedule recordings
      • Slideshow Programme accompanying images and animation
      • Traffic information
    6. Automatically switch for disaster & emergency warnings in case of impending
      disasters in large areas, automatically presenting the audio message, while providing
      detailed information on the screen in all relevant languages simultaneously. Great
      potential to become the surest and widest means of alerting the population to
      emergencies.

Therefore, we urge FCC to take a wide view and consider all options including DRM, if AM is worth futureproofing in the USA.

[This filing also included a number of “Useful Press Links]

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DRM30 on a Smartphone: KTWR Shows Us The Way

Image via the KTWR Blog

Many thanks to SWLing Post contributor, Dan Van Hoy, who writes:

[Regarding the reception of DRM via smart phone,] I happened to find this KTWR Guam post about decoding DRM30 with a smart phone, app, and an RTL-SDR:

Convert Smart Phone to DRM 30 HF receiver!

We are pleased to report successful use of an SDR Dongle used to directly receive and Decode DRM 30 over HF today.

The SDR Dongle is an RTLSDR v3 type connected to an android smartphone using an OTG cable (phone or tablet must be OTG capable).

The Software used:
1. Android driver (free)
2. DRM+SDR Android App ($4.99)

The Frequency of the HF broadcast is directly assigned within the DRM+ SDR app with two settings
1. Frequency in Hertz
2. RF Gain (0-512)

Demonstration video showing Clean DRM decode of AAC Audio and Journaline data along with live metadata.  (our signal was very strong, so only a short wire used for Antenna, DX’rs will need an appropriate Antenna)

Now anyone with a smartphone and a $20 SDR can receive DRM 30 HF broadcasts…

Click here to read this post on the KTWR blog.

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An app to decode DRM?

DRM broadcast (left) as seen via a KiwiSDR spectrum display.

Many thanks to SWLing Post contributor, Richard Langley, who shares this story by Hans Johnson at Radio World:

Can an App Solve the DRM Receiver Problem? (Radio World)

The Digital Radio Mondiale standard for digital broadcasting in long, medium, and shortwave bands offers the possibility to transmit audio, text and pictures.

A few broadcasters use DRM for both domestic and international transmissions. DRM’s largest problem is lack of receivers, especially affordable standalone ones.

Some listeners use an SDR, computer and free Dream software to receive the DRM signals, but this audience doesn’t make up the mass audience that broadcasters are looking for.

[…]AlgorKorea didn’t develop the apps with the intention of solving the DRM receiver issue. They developed them to resolve a problem with FM hearing aids used in classrooms.

So how do they work? The DRM+SDR version couples the popular and inexpensive RTL-SDR to an Android device with a USB OTG adapter.[…]

Click here to read the full article at Radio World.

 

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Tim Whittaker explains route from proof of concept to development of low-cost DRM receiver

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

Here’s some new news about low-cost DRM receiver advancement, and links to an audio presentation explaining the route from proof of concept to development of a low-cost prototype DRM receiver by Cambridge Development. SWLing Post readers might find it interesting:

(Source: DRM Consortium)

16 Jan Low-cost DRM Receiver Advancement

DRM member Cambridge Consultants recently announced an under 10 USD prototype DRM receiver, which was reported in our Newsletter and widely in the industry press. The prototype receiver was unveiled during an Innovation Day at their offices in the UK. Neale Bateman, Encompass Digital Media and a member of the DRM Steering Board, attended the event and spoke to company representative, Tim Whittaker, to find out why the interest in producing this type of DRM receiver. Listen here

Tim also explained the route from proof of concept to development that has helped Cambridge Consultants to produce this low-cost prototype DRM receiver.  Listen here

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KiwiSDR update brings integrated DRM reception!

Many thanks to SWLing Post contributor, Mark Fahey, who shares the following tweet from KiwiSDR:

“Happy Holidays. Software update brings integrated DRM receiver (Digital Radio Mondiale) based on Dream 2.1.1 to all KiwiSDRs. Stock BeagleBone-Green/Black based Kiwis support one DRM channel, BeagleBone-AI Kiwis support four. Development work continues.”

Ironically, I had only recently published a post asking if anyone had ever attempted to decode DRM using a KiwiSDR. Turns out, several readers had by porting the IQ audio output into the DREAM application. Now that KiwiSDR will have a native DRM mode, this will no longer be necessary.

Many thanks, Mark, for sharing this tip! As you say, this is “mega news!”

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Cambridge Consultants design a prototype $10 DRM receiver

DRM broadcast (left) as seen via a KiwiSDR spectrum display.

Many thanks to SWLing Post contributor, Michael Bird, who shares the following news via Cambridge Consultants:

Digital launched, ever so long ago, with TV and radio. So what’s the big story? It’s that the last piece of the digital jigsaw is finally in place: a system called Digital Radio Mondiale (DRM), designed to deliver FM-radio-like quality using the medium wave and short wave bands.

We’re familiar with AM on medium wave and accustomed to the horrible buzz, splat, fade away and back again. But it does have a great advantage in that it will reach for hundreds of miles from a single transmitter. That’s a lot easier than FM or DAB, which both need transmitters every 30 or 40 miles. No fewer than 443 DAB transmitter sites are needed to cover the UK alone.

So take a modern digital scheme, apply some clever (and low cost) computing power, and you can get good sound for hundreds of miles. You get to choose radio stations by name instead of kilohertz, and you can even receive text and pictures. Emergency warning and information features are also built into DRM.

Great technology. But will it fly? Is it available for everyone?

The new news is that India, through its national broadcaster All India Radio, has invested in and rolled out a national DRM service, live today. Just 35 transmitters cover that large country. New cars in India have DRM radios in them now. Other countries like South Africa, Malaysia and Brazil are likely to follow India’s lead.

But something’s missing. The radios that can receive DRM are still prohibitively expensive, especially for those markets that would benefit most. So vast swathes of the world remain unconnected to the services that DRM can provide. Where’s the cheap portable that you can pick up from a supermarket to listen to the news or sport?

Cambridge Consultants has just held its annual Innovation Day, where we throw open our doors to industry leaders and reveal future technology. One of our highlights was the prototype of a DRM design that will cost ten dollars or less to produce, addressing that vital need for information by the 60-ish per cent of our global population that doesn’t have internet or TV. It’s low power, so can run from solar or wind-up.

This design will be ready in 2020, available for any radio manufacturer to licence and incorporate into its own products. We’re doing our bit to make affordable radios for every corner of the globe!

Click here to read this post at the Cambridge Consultants website.

Michael also shares this piece from Radio World regarding this project.

I must admit: there have been so many proposed low-cost DRM receiver designs that never came to fruition, it’s easy to be skeptical. I assume the $10/9 Euro design will be for the receiver chip only–not the full portable radio, of course. They plan to bring this to fruition in 2020, so we’ll soon know if they succeed.

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