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AM radio is a pretty poor standard considering how much power and bandwidth it uses, due much to the very limited modulation technology available in the 1920s.
by audiofish 4y ago
AM radio is a pretty poor standard considering how much power and bandwidth it uses, due much to the very limited modulation technology available in the 1920s.
DRM (no not that DRM--Digital Radio Mondiale) is a modern digital standard that promises much better spectral efficiency, power efficiency and range. See https://www.drm.org/ https://www.drm.org/. It is similar in concept to DAB, using an OFDM carrier, but with more robust error correction and equalisation, and lower bit rate codec to handle larger broadcast areas.
There is a hope that this could upgrade existing AM broadcast infrastructure, allowing rapid coverage of large areas without the expense of building out new towers.
The MW/HF bands are great for coverage because of the longer wavelength, relative to the VHF bands used for FM and DAB.
- lormayna 4y agoI am an huge fan of DRM, but the lack of receivers it's a good limitation for that.
- hulitu 4y ago> and lower bit rate codec to handle larger broadcast areas That's why DAB is crap. Because people are greedy and don't care about quality.
- audiofish 4y agoAgreed, but the alternative here is AM which has never been good quality. DAB was a big step down from FM quality because the choice of codec / bandwidth assigned to stations was pretty bad (and bandwidth == $$!)
- dirkf 4y agoAre you referring to the original DAB (using MP2) or the upgraded DAB+ standard (using HE-AACv2)? I think most, if not all, stations have switched to DAB+. I'm told the quality is better than FM and based on my experience it's certainly not worse as far as I can hear. Of course, since FM is analog it degrades linearly whereas DAB+ is digital: it either works or it doesn't. This might skew the perception of quality.
- audiofish 4y agoYou're probably right. I was put off by early DAB deployments, and haven't tried with DAB+. I would be interested to try again with the new standard.
- cbm-vic-20 4y agoObviously you know this, but AM is absurdly easy to implement. A pencil, razor blade, some wire and an earphone is all it takes to make a crude receiver. https://en.wikipedia.org/wiki/Foxhole_radio https://en.wikipedia.org/wiki/Foxhole_radio
- freedomben 4y agoOne of the first electronics kits everybody gets is a build-your-own AM radio. It's awesome cause it's easy enough for a beginner but also does something cool.
- kjs3 4y agoIndeed. No way that replacing trivial to implement, ubiquitous communications technology with complicated, processing intensive, proprietary solutions could go wrong.
- blueflow 4y agoThis sometimes happens on accident. I had circuits turning into AM radios when i touched them at specific screws or pads, with some random frequency hard-tuned in. At night, when the reception was better, you'd hear voices!