D-STAR, C4FM, DMR

Written on: 2026-05-02 Download PDF

Here is a superficial overview: it doesn't go into detail at all (there are dedicated pages for that), but aims to give a general idea of the situation. I repeat, it is very high-level and you shouldn't stop at this page to decide "this is the system I want". The features not listed here are, in my opinion, decisive, and they can be found on the dedicated pages.

📻 Analog Communications: Good Old FM

Analog is the "radio of all time". You set the frequency, maybe a sub-audio tone if needed, and off you go: you speak and listen. The voice quality is natural; you hear the nuances, the breathing, the timbre. If the signal is good, the audio is clean; if it gets worse, static starts, but you can often still understand. It is a "sweet", gradual degradation. In short, you notice when someone is reaching the limit.

The cons? It's very simple, perhaps too much. No data transmission, no automatic CALLSIGNs, no GPS (except APRS, of course), no internet connectivity other than svlink/echolink. Voice only. And if there is noise, you hear all of it.

💬 DMR: Efficient, but Not for Everyone

DMR is digital; it was born for the professional world (like taxis, security, etc.) and was later adapted for amateur radio use. It is highly efficient: two conversations can fit on a single frequency simultaneously. There is also the possibility to send text messages, GPS coordinates (DPRS), automatically identify yourself...

All very nice, but it's not exactly plug-and-play. DMR radios must be programmed with a "codeplug", a file containing frequencies, IDs, talkgroups, and so on. Not very intuitive for those coming from analog.

Furthermore, the signal does not degrade like FM: when you cross a certain threshold, puff, everything disappears. No static, no hints of voice: just silence.

The AMBE vocoder used by DMR has a "metallic" audio quality: functional, yes, but not very natural.

📡 D-STAR: Pioneering and a Bit Geeky

D-STAR was the first digital system designed for radio amateurs. It has everything: voice, data, GPS, messages. You can even directly contact a callsign on the other side of the world, even if you don't know where they are, without going through complex reflectors. It is flexible and interesting for those who love to experiment.

But it's not all roses: the audio codec is proprietary (AMBE), which makes completely open implementations difficult. And the network, though present, is not as widespread as the DMR world. Furthermore, almost everything revolves around ICOM and possibly Kenwood: if you want to use D-STAR, it's hard to step outside their ecosystem.

🔊 Yaesu System Fusion (C4FM): The Convenient Compromise

Fusion is Yaesu's offering. The beauty is that some radios and repeaters understand both digital and analog and switch between them automatically. This makes it an excellent middle ground for those wanting to try digital without throwing away their FM experience.

The audio quality is among the best in digital. It is clear, less "robotic" than DMR. The radios are easy to use, often having highly readable displays and less cryptic programming.

The disadvantage? Yaesu's WIRES-X network is somewhat closed: to be part of the official nodes, you must use Yaesu hardware. And in Italy, the presence of Fusion is decent, but not at the level of DMR.