Photo by Brock Wegner on Unsplash
Many thanks to SWLing Post contributor, Alan, for his recent article in Radio World titled “The Modernization of Broadcast Radio.” In it, Alan argues that the proposed “AM Radio for Every Vehicle Act” in the U.S. should go beyond preserving legacy systems and instead embrace Digital Radio Mondiale (DRM) as the future of terrestrial broadcasting. Drawing comparisons with digital transitions in countries like Norway, Switzerland, India, and China, Alan highlights the potential to reduce transmission costs, increase coverage reliability, and enhance emergency communications — all while offering a path to modernize U.S. broadcasting infrastructure.
What are we arguing about? Why do people keep bringing this up for the US? It doesn’t exist in the US. It’s unlikely it will be standardized in the US for 20 or more years or ever. I think we all understand the benefits, but the never ending series of posts on why it’s great, is meaningless in the US. Please stop extolling the virtues of DRM in the US as it ain’t gonna happen. We have far larger issues to worry about here. Great for India, but, honestly, no one in the US cares what type of radio they have in India.
DRM is a failure from a business perspective. Very few shortwave receivers support it and the manufacturers that do make receivers that are overpriced and poor performing.
DRM is also a bandwidth hog and hard to decode reliably. It will remain an esoteric mode for weather broadcasting.
AM works and is reliable. Leave it at that. This mad obsession with changing reliable legacy systems and replacing them with proprietary and expensive “solutions” that deliver compromised performance and inferior gains needs to stop. Screw the greedy corporations and the bean counters who have all the common sense of a flat tyre.
AM Bob,
You are not in India. There is over 7 million cars containing DRM receivers installed on the production line and there is no price increase for this. All common brands are installing them voluntarily. So this number of receivers is increasing at the same rate as car sales.
This has happened because there are 37 high power DRM transmitters between 530 – 1609 kHz. A few of those transmitters are a million Watts. The highest power of AM in the USA is only 50 thousand Watts. In addition All India Radio have 4 high power high frequency DRM transmitters..
As for bandwidth it is selectable from 4.5 – 20 kHz below 30 MHz, 100 kHz above. Compare this to AM in your country AM is 20 kHz but the channels overlap by 10 kHz. FM is 200 kHz wide. When you add HD radio the bandwidths double. So in the VHF band HDradio is 4 times the bandwidth of DRM. The only company charging listeners, broadcasters and manufacturers for HDRadio is Xperi. DRM and DAB+ are free to all
DRM in the USA is unreliable because there are no DRM signals targeting North America. There hasn’t even been any trials of DRM inside the USA. This is because the National Association of Broadcasters paid Ibiquity to develop the HDRadio standard where to prevent interference the maximum digital signal power in the FM band is 4 % of the FM signal.
AM Bob,
You’re absolutely factually correct. DRM is indeed a disaster, a disaster which size is now so big it’s impossible to cover up. The only thing needed to get a grasp of its size is opening the DRM Consortium website. In the early 00s, they had most of the major national international broadcasters on board – Deutsche Welle, RTL Luxembourg, Radio France Internationale, Radio Netherlands Worldwide, Vatican Radio, Polish Radio, Czech Radio, Radio Exterior de Espana etc., lots of domestic MW tests in countries like the UK, Germany and so on. It was deeply believed to be the next ‘big thing’ for mediumwave and shortwave.
Fast forward to 2025 – what’s left of these promises? Nothing! Every one of these trials led to the rejection of DRM. The DRM Consortium is now, completely unironically, promoting reception of broadcasts from North Korea, because this is what they have – no receivers, no significant broadcasts, no nothing.
The emperor has no clothes and this is why this campaign to push DRM works precisely this way. The pundits cannot deliver anything besides these campaign slogans about dreadful AM carriers. Ask any substantial question, even the most basic one like: what are the types of receivers available, what stations use DRM, and you always get one of these: unrelated marketing slogans, technobabble, India travel advice (remember: this is the most successful rollout of DRM, because a single station has adopted it – 100% more than in any other country!), sometimes conspiracy theories about various organizations working tirelessly to undermine the great DRM.
It’s kind of amusing, because you don’t always see an organization repeatedly pushing a product that has been rejected by everyone who’s actually tried it, not seeing any of its own faults, not delivering any meaningful improvements – just trying to push this same thing over and over again. But as with everything, there’s a point when the reality prevails.
Millions of receivers in cars, and now a new low cost portable has just been released in the Indian market, made in India using receiver module in the UK by very smart hardware and software engineers. It is highly integrated.
None of this is aimed at the USA market which is still using broadcast technology which is over 100 years old. Stay in fairy land.
What is the “new low cost portable” that “has been released”? What is the manufacturer and model? Where it can be ordered?
I have told you before where you can get the DRM1000 module outside of Asia.
There will be none marketed in areas where there are no transmitted signals such as the USA. It will be a waste of money and time.
You will have to go to India and buy almost any new car if you want a car receiver.
https://www.radioworld.com/tech-and-gear/digital-radio/solar-grove-introduces-a-personal-drm-receiver
> I have told you before where you can get the DRM1000 module outside of Asia.
And I have repeatedly stated that modules are aimed at device manufacturers, which I am not – I am a radio listener, therefore to listen to DRM broadcasts, I need a complete receiver. Similarly, when I want to call someone, I need a complete phone call, not just a GSM modem. When I want to write this comment, I need a complete computer, not just a CPU. It’s really simple!
> There will be none marketed in areas where there are no transmitted signals such as the USA.
The DRM consortium advertises on its website that the BBC, Radio Romania International, Music 4 Joy and Radio New Zealand Internationals can be received in Europe. Do you know any European-based store selling any models of DRM-capable receivers?
>You will have to go to India and buy almost any new car if you want a car receiver.
I always thought that being able to tune in to broadcasts coming from abroad was to be one of the most prominent selling points of DRM, hence the name “mondiale” meaning “worldwide”. They even advertise that on the DRM website – quote:
“Because DRM is ideally suited to long range broadcasting, you can stay tuned to the same station as you cross regional and national boundaries and move from one country to the next. Imagine, for example, driving across Europe, for pleasure or as part of your job, and being able to stay tuned to your favourite radio station from back home – absolutely not other system can deliver that.”
But in reality, it seems that what the DRM Consortium now means by “worldwide” is “in India”. I don’t have an issue with that, but this is core of the issue with their approach – they obviously can switch their focus to a single market, but in that case, what’s the point of claiming that DRM should be mandated in the US when the only answer for someone wanting to obtain such a basic thing as a radio receiver is “go to India”? How is that supposed to work?
We live in times where every imaginable kind of Chinese crap (not to insult lots of good quality products they make!) is immediately available worldwide on Aliexpress, Temu, etc, yet the only thing you can’t get anywhere is a DRM receiver? Either India’s DRM rollout has been so successful that the country is sucking up all the manufacturing volume, or it’s just a dead business that no one wants to get their hands on.
Can we try to estimate which one may be true?
Let’s assume that the DRM rollout by All India Radio is indeed an overwhelming success. It has been declared as the official standard for digital broadcasting in the country. People are buying all types of receivers, portables, for cars, for rickshaws etc. and are enjoying this great, long awaited progress brought by DRM – crystal clear, FM-quality, CD-quality, concert hall quality – call it as you wish – sound. AIR saved gazillions of rupees that were being wasted on 100-hundred year-old AM with carriers, interference and all other scary things. Hooray! Everyone’s celebrating.
So let me now ask a very simple question: why did NO OTHER station adopt it? Like, you know, it’s not a dictatorship with a single central radio station, they have lots of other ones, Wikipedia states more than 369 private FM stations. Why did NOT A SINGLE ONE of them convert to DRM? Are their owners plain stupid for not seeing the benefits, or is DRM just a white elephant government project with no real impact, no real adoption and plainly disregarded by the market?
As for the “Solar Grove N88”, I see that in fact, it has not “just been released in the Indian market”, the only thing released so far is the PDF file on their website. Even the content of this PDF contradicts your claim – it says “The new All-Band Analog and DRM radio is expected to be available for purchase in Q4, 2025 via direct sales through SHEMISH GROVE SOLUTIONS and authorized dealers”. Today we are in Q2, 2025, not Q4. We are still to see whether these expectations materialize. I support their efforts in bringing an affordable and widely-available receiver, but seeing all the other companies fail miserably at it (like in the case of Gospell GR-221, that was supposed to include this DRM1000 module and be available in 2024, but as it’s always been the case with DRM Consortium announcements – it doesn’t exist anywhere), for now I remain skeptical.
DRM suffers from several problems. First it doesn’t handle selective fading well. Of course, neither do the current in band on channel digital formats. But if DRM is to take hold, it needs to offer something that the current technology doesn’t have. And right now, I can’t think of anything it does significantly better than the MW AM HD signals.
Jacob,
Selective fading is caused by multiple reflections from the ionosphere and is worst in the high frequency bands. My article is recommending 47 – 88 MHz which is above 30 MHz in the VHF low band which is not usually reflected from the ionosphere, it goes straight through. It is in the broadcaster’s interest to maximise the radiation towards the horizon and in some cases below as well and not send the radiation upwards.
As for high frequency bands the broadcaster should use mode C and D which is designed for selective fading. DRM is sent in bursts to allow for reflections which arrive later to be ignored. Mode D has the longest gaps.
The multiple ‘carriers’ of DRM also have pilot signals added to allow the receiver to measure the relative levels and apply the inverse to an equaliser. The number of pilot tones varies depending on the mode. The critical factors include the signal strength at the receiver, the signal to noise ratio and the MER ratio used in the transmitter.
It is much better than MW because the high frequency audio is present and when stereo is transmitted even in the high frequency bands, reflections do not move the image.
As for HD radio in the AM band, it is almost dead due to the use of adjacent channels to carry the data signal which is about <0.1 % of the carrier power in hybrid mode and in pure digital mode 90 % of the power is the carrier which contains no data.
The DRM audio uses the latest audio compression algorithm xHE AAC® which produces very good stereo sound at much lower bit rates. HD radio uses the old MP3 compression algorithm which has been modified so only HD radio receivers can decode when the royalties for HDRadio® has been paid by the manufacturer. It addition the available bit rate is selected by the broadcaster. In HDRadio® the HD2 – HD4 channels are only 20 kbit/s each. If errors are high the receiver mutes. It is only HD1 which blends back to analog and maybe even analog mono.
Lastly in HD radio the data below the station frequency is identical to that above the frequency, where as in DRM all data is unique allowing for more error correction.
Hopefully North America, can adopt the DRM, if it is found to be the better system! But, now for the transmission towers. Will their height be an obstacle to low flying aircraft, as FM towers are usually built quite high as transmission is “line of sight”..?
This aspect of tower siting is regulated by the US Federal Aviation Administration and hasn’t been a problem here since AM broadcasting began. There have always been tower strikes by aircraft but they are pretty rare.
Michael,
In DRM all of the transmission power is given to the data. In HD radio in the FM band the digital power is a maximum of 4 % of the FM power.
No more E-mails I`m tired of reading them Go Away!
Unsubscribe?
Interesting.
It’s unfortunate that Digital Radio Mondiale shares it’s Acronym with Digital Rights Management, which is causing a huge disruption of the ATSC 3.0 rollout in the television end of the spectrum.
Why stop with DRM receivers? Let’s also mandate that all cars must be flying, just like the ones from The Jetsons. I know it may sound ridiculous, but in fact, the status of flying cars is surprisingly similar to the one of DRM receivers – only single pieces are known to exist and you can’t actually get any of them from any major store. So it’s kind of hard to foresee lawmakers mandating something that doesn’t really exist on the market.