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Comment by idunnoman1222 | Hacker News Reader

Why are they calling this long wave instead of just AM radio?

Cause longwave (148-283 kHz) is only part of AM radio. Most of it is in medium wave (525-1705 kHz) and some shortwave (2.3-26 MHz).

LF, MF, and so on are bands, or frequency ranges. AM is a modulation technique. It, like FM and others, can be used on any band (although regulations can limit this).

Long wave != AM: long wave implies AM, but not vice versa (AM can be - and usually is - used on medium/short frequencies)

> long wave implies AM,

It doesn't: There's a lot of non-AM/non-voice stuff on longwave, most notably various digital time beacons (WWVB in the US, DCF77 in Western Europe etc.)

I think this was an honest question?

I have noticed that regular medium-wave AM seems to have decent propagation (though maybe not many thousands of miles) and also improves at night.

The US often just says 'AM radio' to refer to the MW band, because they don't have commercial broadcasting on the LW band, so there's no need to disambiguate. In the UK we usually specify LW or MW because both bands are in use for 'AM radio' (for now ..).

Same way we just say FM for the 88-108 broadcast band. Were there two FM broadcast bands, we'd need to give them different names.

In the UK, you have a button on your radio that switches between AM FM and a third option? Or just those two?

Because commercial AM radio is 540-1710 Khz in the USA. Also note that aircraft use Amplitude Modulation even though they are in the VHF radio band.

It's at a lower frequency, 148.5 to 283.5 kHz.

AM is a type of modulation which is widely used by many different services (eg Shortwave broadcasting, CB radio, Aircraft VHF, etc).

However "Longwave and Mediumwave Broadcast" unambiguously refers to that service.

Does my wavelength imply my modulation technique?

Well, yes and no. Inside specific areas of all bands there is a convention to use specific modulation. On the Amateur bands, whilst you are free to use whatever you like, there are conventions that CW, digital, SSTV, SSB and FM are generally grouped into sub- bands. It helps people find each other, so is pretty useful. If your receiver is set to FM you might not notice a CW signal. On other commercial bands the mode is enforced.

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