When it comes to digital broadcasting, we’ve surely heard of DRM broadcasting. Today, let’s briefly discuss what DRM is.
DRM stands for Digital Radio Mondiale, with “Mondiale” being an Italian and French word meaning “world,” so DRM broadcasting can be referred to as global digital broadcasting. DRM is an open standard adopted by many countries to replace existing traditional analog broadcasts such as FM and AM radio.
Frequency Bands
The first question is, which frequency bands does DRM broadcasting use?
We commonly use radios to listen to analog broadcasts, which are transmitted in AM format in the LF, MF, and HF bands. These bands cover large areas and can be used for provincial or national level broadcasting.
In the VHF band, broadcasts are typically in FM format. This band covers a relatively smaller area and is commonly used for local level broadcasting.
DRM can be used in all of these bands, meaning DRM broadcasters can choose different bands for broadcasting based on the coverage required. Below 30MHz, it’s referred to as DRM30; above 30MHz, it’s called DRM+.
Advantages
The second aspect we must discuss is the advantages of DRM broadcasting compared to analog (AM/FM) broadcasts, particularly from the perspective of reception.
Firstly, there’s the audio quality of the broadcasts. If you’ve ever experienced digital audio modes like DSTAR or DMR, you’ll notice a significant difference in audio quality compared to analog signals. Similarly, as a digital broadcast, DRM broadcasting offers notably superior audio quality compared to analog broadcasting.
The second advantage might be a bit harder to grasp: DRM broadcasting can transmit three different programs simultaneously on the same frequency, greatly improving frequency utilization efficiency. This naturally means more channels can be received. For example, take a look at the image below, which shows a China Radio International DRM broadcast at 6.03MHz. At the time of the screenshot, only one program was airing on that frequency. However, when multiple programs are broadcast simultaneously, there will be more options to choose from as indicated by the arrows.
The third advantage is that DRM broadcasting can transmit not only audio but also data. This means receiving images, SSTV, and other possibilities become feasible.
There are other advantages as well, such as the fact that DRM broadcasting requires only 50% of the transmission power compared to analog broadcasting for the same coverage area, but I won’t list them all here.
How to Listen
There are two methods I’ve observed:
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Purchase a radio with DRM broadcasting capability. (This is a no-brainer.)
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Use existing devices like SDR receivers and employ external decoding software (e.g., DREAM). The operation is similar to decoding FT-8 mode: the SDR receives the audio signal, which is then passed to the external software DREAM for decoding, thus achieving the purpose of decoding DRM broadcasting.
For those familiar with the KiwiSDR project, you can also experience DRM broadcasting reception remotely using pre-set up SDR devices online. I won’t delve into the operation details here.
Current DRM Broadcasts
This website – https://www.drmrx.org/drm-broadcasts-all-by-time/ – has a schedule of DRM broadcasts around the world for your reference.