Talk:AM broadcasting
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i thought short wave went up to 29,999 kHz? tahstw hat it does on my sw radio. -fonzy
You could be right. My Sony only goes up to 26100 kHz, though, which is where I got the figure from. Feel free. GrahamN 19:52 Jan 23, 2003 (UTC)
I have a digital one(not DAB, digital dial) i think the MW one is wrng too. as it goes up to 17,010 khz on mine, then sw starts on 17,011 starts. - i dont really know enough about radio btu i am shore that sw goes up to 30 Mhz. -fonzy
The current American AM band extends from 540 to 1700KHz wheras the official European MW band is from 531 to 1602 KHz also in both cases there are stations operating "just" outside the official band so the defacto band goes from 520 to around 1720 KHz (confusingly some older European radios mark dial position in metres instead) Officially "Shortwave" (HF) covers the range 3 to 30 Megahertz however there is no (legal) shortwave BROADCASTING above 26.1 MHz (remember the radio spectrum is used for many other things besides broadcasting) also Most people consider the bands between the top end of the meduimwave band and 3 MHz to be "shortwave" even if they are not officially classed as such. Most "Shortwave" radios only cover the most popular broadcast bands (some only cover the "49 Metre"/6 MHz broadcast band) Some treat Shortwave as a single "band" while some (particualrly analouge tuned) radios split it up into smaller ranges (often marked "SW1" "SW2)" etc to make tuning easier.
Does this help? It's a bit surprising that the definitions seem so vague. GrahamN 20:16 Jan 23, 2003 (UTC)
All thsi conflicting data hurts my head :-s, we need someone who really is an expert on this. -fonzy
How about if we round the numbers off and qualify them with "approximately"? GrahamN
Yes do taht for now might be good to put an HTML comment on the paeg saying if you deffently know what it should be please say. -fonzy
The trad. modulation used for telegraphy (carrier either on or off) is called CW. Although the amplitude is modulated per se (0 or 100%), the term AM is never used for this. I have thus removed the following sentence:
- ... for radio telegraph communication early in the 20th century ...
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- Okay. I think we really could use an article on radio telegraphy, are you up to it? I had thought that it was on AM frequencies; I remember hearing lots of Morse Code on medium and shortwave as late as the mid 1970s, was that something different from what is ususally called radio telegraph? -- Infrogmation
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- The point is it is not "AM" (as in amplitude modulation), so it is not "AM radio". Even though it happened to occur in bands also used for AM. My suggestion is that the term "AM radio" should mean "public broadcasting using amplitude modulation", while "AM" should mean "amplitude modulation" in the more technical meaning. Morse using CW is neither. Sorry, I don't know too much about radio telegraphy history and such, so all I can contribute would be a silly stub. -- Egil 18:14 Feb 4, 2003 (UTC)
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- Okay. I think we really could use an article on radio telegraphy, are you up to it? I had thought that it was on AM frequencies; I remember hearing lots of Morse Code on medium and shortwave as late as the mid 1970s, was that something different from what is ususally called radio telegraph? -- Infrogmation
Not all morse telegraphy is "CW" Some is "MCW" "FSK" etc Actually even "CW" is a bit of a misnomor. It should really be termed "ICW" (interrupted continous wave)
[edit] frequencies
The term "commercial radio broadcasting" in this context is rather confusing (Long wave is used for commercial radio broadcasting in Europe, Africa, Asia,.....) Since the majority of Longwave and Shortwave (as well as much Mediumwave) broadcasting is infact NON-commercial. Also Long wave is NOT used for broadcasting in "Australasia". In the 1930's when the ABC was being established in Australia t was originally proposed that LW should be used but a for various reasons mix of MW and SW (and later FM etc) was decided upon instead.
