A DRM super assistant for the traditional listener

Being a tuning facilitator is an act of humanity

My father often calls me and says, “Ricardo, put on that station I like.” I already know which one he means, but an intelligent system could recognize it based on usage, ask for hints about what he wants to hear, or even suggest another station he might enjoy even more. For him, a simple voice command would already be a game changer, it would give him the independence to listen to what he wants without needing to ask someone else.

Cheaper solutions than AI-based tuning facilitators

Of course, we must take into account all listener classes and possibilities, which can vary greatly within a single country and even more when comparing countries with different economic and technological conditions. Therefore, a low-cost system with easy station search could rely on channel-based organization. The standards for this channel mapping would be a more trivial discussion, limited to the technical and marketing sectors.

Let’s say I want to tune in during the week and channels 14, 26, and 8 are the only ones I care about, the effort required to find them on a DRM receiver would be as simple, or even simpler, than turning the dial on a traditional analog radio.

But What About Countries Where the 520 to 1710 kHz Band Is Unavailable?

This is precisely where DRM delivers a checkmate: it extends into other bands that previously had no commercial use for AM or FM broadcasting, but can now be reimagined. This allows us to avoid the hybrid model, where analog and digital signals coexist in the same frequency range, a structure that, over time, has proven to be a barrier to the mass adoption of digital radio.

“Will the Listener Find Me on Another Frequency? On Another Band?”

This has been one of the most simplistic misconceptions holding back the debate on digitalization. It was precisely this fear that led to the development of hybrid systems like IBOC, which tried to maintain analog and digital signals side-by-side, a huge waste of energy and complexity just to keep two systems artificially coexisting in the same channel.

Gradualism

The insistence on hybrid systems led to gradualism and gradualism is like taking an antibiotic for only half the prescribed time. As a result, the patient doesn’t heal, the bacteria become more resistant, and a new treatment will need to be more aggressive in order to be effective.

Alternative Bands

Alternative frequency bands must be seriously considered, as they allow for new digital stations to be deployed without conflicting with existing analog transmissions. DRM was designed with this flexibility in mind, capable of occupying adjustable channels with high spectral efficiency and minimal interference.

Precisely to avoid scattering frequency bands, which is one of DRM's major advantages over its competitors, the introduction of an alternative band must include search facilitators. Just like with digital TV, viewers were never required to memorize any new frequencies, in fact, most didn’t even know the old analog TV frequencies. It worked almost like a factory preset, similar to the old system of saving AM or FM stations as preset buttons (1 to 12 or 1 to 20) on car radios, depending on the receiver model.

Even if the chosen band is the traditional AM, the possibility of organizing it into channels could also make it easier for stations to establish memorable numbers in the listener’s mind, encouraging adoption. For example, a station could promote on FM:

“Tune in to XYZ Radio in DRM AM, pure sound over long distances, now on Channel 14.”

❗️The focus must be on making it extremely easy for listeners to find stations in the digital environment. This is where our energy should be invested! ❗️

In a well-structured digital environment, stations can be perfectly organized by name, brand, or even historical frequency, without any loss in user experience.

Imagine giving your father a smart digital radio: with a simple voice command, he could say “find BBC London, channel X,” or use a simpler model that, after two or three days, he would naturally remember that his favorite station is on DRM AM channel 12.

It’s time to abandon the illusion that listeners won’t be able to find us if the address changes. In fact, technology already provides ways to ensure the user doesn’t even realize that the frequency or band has changed. What matters is the continuity of experience, not clinging to analog-era numbers.

Image inspired by the visual scheme from publicaccess.se

Having so much space and so many channels to offer is an achievement earned with distinction by the DRM system. To prevent listeners from getting lost in a sea of frequencies, it makes perfect sense to plan for channel-based navigation as a simplification bridge — especially for more traditional listeners.

Smart Use of the Spectrum: Comparing DRM, DAB and HD Radio

The image immediately shows us that the DRM system, combining both its DRM up to 30 MHz and DRM+ versions, covers a much larger portion of the spectrum compared to other systems. But that’s only part of the answer. It’s not enough to occupy a wide frequency range; what truly matters is how efficiently that range is used in practice.

Let’s imagine, for example, that a digital transmission required a very wide bandwidth to perform satisfactorily. In that case, this broad coverage could be misleading, resulting in only a few truly usable channels. The good news is that DRM uses the bandwidth it occupies with great efficiency, adapting its parameters according to technical needs, robustness requirements, and coverage goals. This turns its wide spectrum usage into a real asset, versatile and manageable in many different ways.

To illustrate, consider this analogy: imagine the visual scheme in the image above represents bookshelves, and the colors represent books from different publishers. At a glance, it’s clear there are many more books from the “DRM Publisher” spread across the shelves. But that’s not all, these books not only appear in greater numbers, they also contain more information per page than the collections from other “publishers”: more functionalities, more data, more technical possibilities.

Band Management

When we examine how DRM occupies the spectrum, we are led to rationalize that distribution. And this is where the system becomes even more powerful: DRM not only provides enough space to accommodate all existing stations, but also retains a generous margin of available capacity, ensuring scalability for many years to come.

This level of efficiency opens the door for applications beyond traditional radio. With digitalization in place, previously underutilized or idle frequency bands can be repurposed, optimizing the use of a valuable and limited public resource.

Spectrum Coordination: A Matter of Organization, Not Limitation

It’s clear that medium and shortwave bands require, in addition to suitable technology, effective regional and international coordination among neighboring, and even distant countries to avoid unwanted interference. This necessity arises from the nature of signal propagation in these bands, and from the vulnerability of analog signals when faced with nearby digital transmissions or overlapping frequencies.

Appendix

The information below was collected from widely accepted sources and may contain minor inaccuracies, but the objective is to understand the spectrum efficiency of each digital broadcasting model.

Main Broadcasting Systems and Their Respective Frequency Bands:

• AM (Amplitude Modulation) /Band: MF and part of LF / Type: Analog

• FM (Frequency Modulation) / Band: VHF / Type: Analog

• DRM30 (Digital Radio Mondiale for AM and Shortwave) / Band: MF and HF / Type: Digital

• DRM+ (DRM for FM) / Band: VHF / Type: Digital

• DAB (Digital Audio Broadcasting) / Band: VHF / Type: Digital

• HD Radio (AM and FM) / Band: MF (AM) and VHF (FM) / Type: Digital

System	Typical Bandwidth	No. of Programs per Channel	Spectral Efficiency (Programs per MHz)	Remarks
HD Radio	~400 kHz (AM) / 200 kHz (FM)	1 to 2 (with limited quality)	Very low	Requires adjacent analog spectrum. Highly inefficient.
DAB+	1.536 MHz (multiplex)	8 to 20 digital programs	Medium	Suitable for large networks but requires wide spectrum blocks.
DRM	4.5 kHz to 100 kHz (scalable)	1 to 4 programs per 100 kHz	High to very high	Flexible and scalable. Ideal for efficient spectrum use.

When it Comes to Spectral Efficiency… DRM Wins

In terms of spectral efficiency, that is, how well the available frequency spectrum is used, DRM (Digital Radio Mondiale) is the clear winner when compared to HD Radio and DAB+.

Why Is DRM the Most Efficient?

• Adaptive Modulation and Variable Bitrate

  DRM can adjust signal robustness and quality depending on the broadcaster's needs and coverage goals. This allows for more content (audio + data) to fit in less bandwidth.

• Flexible Channel Bandwidth

  DRM can operate in channels from 4.5 kHz (e.g., in HF/shortwave) up to 100 kHz (in VHF/FM).This adaptability enables optimized use based on infrastructure and transmission goals.

• Multichannel Capability in Narrow Bands

  DRM can deliver up to 4 audio services plus multimedia data in just 100 kHz — no other system offers this level of efficiency.

• Legacy Spectrum Compatibility

  DRM can be implemented without the need for major spectrum reorganization, including in the AM band now largely vacant in Brazil, making it ideal for reusing legacy frequencies.

Summary Table

Criterion	Winner
FM Efficiency	DRM
AM Efficiency	DRM
Shortwave Efficiency	DRM
Efficiency in Large Spectrum Blocks	DAB+
Lowest Overall Efficiency	HD Radio

If your goal is to make the most efficient use of the spectrum, especially in countries with fragmented spectrum, limited infrastructure, or available AM bands (as is the case in Brazil), DRM is technically unbeatable. And in countries where the AM band (520–1710 kHz) is no longer available, alternative frequency ranges supported by DRM can and should be considered.