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Comment by gpvos | Hacker News Reader

AM is even simpler and even more robust. I think we never should have switched it off.

In the US, AM is still very common and there are efforts to keep it that way: https://news.ycombinator.com/item?id=40234871

AM sounds painfully awful

For a while there was an AM Stereo which sounded much better

And there are some stations in the US still broadcasting in AM Stereo AKA C-QUAM, if you have an AM stereo capable receiver that is.

https://en.wikipedia.org/wiki/C-QUAM

You should listen to some DAB+ for comparison. I heard that 56kbps can make wonders. /s

That's he-aac so 56kpbs is not that bad, it gets dicey below 32kbps when you need tricks like parametric stereo. But he-aac's spectral band replication does add metallic taste to everything, i would agree

Agree for music. Hard disagree for voice.

Especially in the car! I can’t make out voices on FM at all. But AM, easy.

That "sound" is partially due to the design of the current AM system. It was built to pack more transmitters into the allocated frequency range.

There are no technical impediments to high fidelity audio because of amplitude modulation. In the past the big limitation was the bandwidth of intermediate frequency (IF) amplifiers in the receivers which were typically tuned for maximum gain and not flat audio band response. The transmitters have flat response out to the legal limits. Radio stations have a monitor receiver that has proper IF audio response and the sound of those are very good.

So does DAB. It’s way the hell compressed.

Not that I care too much, as I basically only do on demand media these days.

I wouldn't say it's more robust. One pass under a bridge proves that AM has problems.

It also has lower fidelity.

AM only has lower fidelity because of the low broadcast power and shitty receivers. 80 years it was much higher quality with the huge transmitters and high quality tube radio.

But AM isn't switched off.

Depends where. In Switzerland it is.

I looked for a source for this but can't find any mention of it.

"Most European countries are now running a reduced AM radio service with fewer transmitters, fewer services and lower power. Albania, Andorra, Austria, Belarus, Belgium, Croatia, Estonia, Finland, Norway (except Svalbard), Slovakia, Sweden and Switzerland have completely closed their AM radio services. Denmark retains a part-time long wave service for mariners. Lithuania has closed domestic AM radio, but retains a medium wave transmitter for international broadcasting. Only Cyprus, Hungary, Iceland and Romania (together with England, Scotland, Wales, Northern Ireland and Spain) are continuing with a comprehensive AM radio service."

http://frequencyfinder.org.uk/AM_Other_Countries.pdf

This is outdated. Denmark closed its long wave transmitter last year. The biggest hold out is bbc radio 4 and they stopped special long wave programming and the service is only still on the air because it doubles as a digital signal for some power meters.

My new car doesn’t even have an AM tuner

Because it raises the costs (antenna + cable) so the profit is lower.

Most European countries have switched off all their major transmitters, or are preparing to switch off the last few that are left. E.g., in the Netherlands, there are now only low-power hobbyist stations, which will remain I think, but have a near-zero audience.

LW is simpler still and incredibly robust. It's a pity it has been turned off.

LW isn’t a modulation

Long wave is a frequency band just like medium wave. Amplitude modulation is used on both; it's the same technology, LW needs much larger antennas though. FM is often used to refer to a frequency band, but that is actually called ultra-short wave, and frequency modulation is used on it.

I'm going to dust off my spark gap radio.

It sucks though, sounds horrible.

AM was switched off?

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