Talk:Microwave
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[edit] Uncategorized
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- (added heading for clarity--Tunheim 10:34, 31 January 2007 (UTC))
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[removed inappropriate comments]
For future reference to edit this section: "copy the link location" for the edit link, change section=1 to section=0 on the link.
I hope to find free time to contribute to this page, especially a branch on passive microwave remote sensing.
edited by: jbenjam@aos.wisc.edu
[edit] Needs editing?
"There is also much more bandwidth in the microwave spectrum than in the rest of the radio spectrum."
Does not make any sense - does it mean "free (unallocated) bandwidth" ?
No, higher frequency (shorter wavelength) => more bandwith.
Again, makes no sense. Higher frequency => more *unallocated* bandwidth ?
No, it has nothing to do with allocated bandwidth, its sheer data capacity. Higher frequency = more bandwidth = higher data capacity.
For example, thats why 2.4GHz cordless phones have a clearer signal than 900MHz cordless phones. 2.4GHz is higher frequency than 900MHz, thus 2.4GHz has more bandwidth to transmit more audio data which makes the audio connection sonud clearer. Probably not the best example since the quality of the handset and phoneline are major factors but yapping about 802.11 bandwidth would probably just confuse you more.
Someone needs to clean up ths talk page. Up at the top it says I will pull out a knife after finding your home by your ISP address. Is that possible? Anyway... for some reason I cannot edit what is at the top of the page.
All this microwave talk is fascinating though!
This stuff about bandwidth is kind of misleading. Just because 2.4 GHz is higher than 900 MHz does not mean that there is more bandwidth to transmit a signal. The bandwidth is regulated by the FCC in any kind of commercial application, not by the frequency that is being used. An example will probably explain things best. Suppose you are broadcasting a signal that requires 10 kHz of bandwidth (typical AM radio). At typical AM broadcast frequencies from 540 kHz to 1600 kHz that means you could have (1600-540)/10=106 AM stations all operating at the same time (this is called frequency division multiplexing). If these stations were instead broadcasting in the range of frequencies from 540 MHz to 1600 MHz but still using 10 kHz each you could have (1600000-540000)/10=106000 AM stations all operating at the same time. Modern digital communication systems may require bandwidths of 10s of MHz. If you tried to use frequency division multiplexing to send a signal with a one MHz bandwidth in the AM frequency range you could only send one signal at a time: (1600-540)/1000~1. But in the frequency range from 540 MHz to 1600 MHz you could send over 1000 such signals. I hope it is clear that a 2.4 GHz cell phone does not use 2.4 GHz of bandwidth and that a 900MHz phone does not use 900 MHz of bandwidth.
Right on ! That's what I was talking about, higher frequency need not mean higher bandwidth ! Whenever someone says 2.4GHz, its a 'carrier frequency', there is some 'bandwidth' around the carrier frequency.
[edit] can a microwaves oven be used for sterilisation?
I was just wandering if it kills bacterias and could be used to kill pests like lice or fleas on stuffed toys without adding water. Dominique
- My friend says you can put your toothbrush in the microwave to sterilize it when you are sick. YesJesusLovesYou 07:03, 24 February 2007 (UTC)
[edit] Differing Values
The Pozar reference appears credible, but the values for frequency and wavelength are significantly different than what's commonly taught at the university level, with wavelengths from 10 cm to .001 cm, and frequencies from 3*10^9 to 3*10^12 Hz. Source: http://csep10.phys.utk.edu/astr162/lect/light/spectrum.html Recommend updating the first paragraph and citing a better source. Mugaliens 16:58, 22 August 2006 (UTC)
[edit] Why are they called Microwaves?
This article needs a bit more history. Who called them "microwaves" and why? What parameter is "micro" - the wavelength isn't in the micron range, so what is the "micro"? Please expand the article to explain this stuff.149.167.200.118 05:09, 3 September 2006 (UTC)
[edit] Band links wrong/misleading?
The D, E, and F band links go to pages on radio frequencies. Is something wrong here?
[edit] Form of power?
Ok, if you put a light bulb in a microwave it turns on, couldn't this theroy be used to transport electricity through the air?
[edit] Turntables
Why do microwaves have turntables? Since the device is heating the whole compartment, do they really do anything? --David Youngberg 14:22, 3 November 2006 (UTC)
- David, I believe this is because microwaves ovens do not evenly distribute the emitted microwaves to all areas in the oven. I think this question might be better addressed under the Microwave Oven entry. --Arterion 22:53, 15 November 2006 (UTC)
- Actually this is because microwaves do not fill the entire oven. They actually only penetrate into whatever is being cooked by a few centimeters, and so there are large shadow regions in the oven. The turntable simply helps make cooking even. —The preceding unsigned comment was added by 88.108.79.57 (talk) 21:00, 6 February 2007 (UTC).
[edit] Microwaves vs. microwave
When talking a bout a term I am under the impression that the plural form is normally used. Should we then rename the article? --Tunheim 10:36, 31 January 2007 (UTC)
[edit] Misattributed discovery
They were *not* discovered by Max Lazarus.
[edit] Heating different states of matter
Can anyone tell me why it is that water in a gaseous state isn't heated as easily as water in a liquid state. It says it why it doesn't work with frozen water, but a gas is even less dense than a liquid, so wouldn't it more freely rotate. Is that why, because it is to free and their isn't enough friction? It makes sense, but is that true? 74.225.66.28 21:25, 21 February 2007 (UTC)
[edit] Frequency Range
The paragraph about vacuum tube based devices doesn't really belong. It seems like useful information so I don't want to just delete it, but it's definitely in the wrong section, if not article. --Jw 14:12, 1 March 2007 (UTC)
[edit] Unsourced Comment
I'm relatively new in editing, but i'm trying to be bold. I am removing "For the proven dangers of microwave ovens visit this page http://www.ghchealth.com/microwave-ovens-the-proven-dangers.html" from Health Effects because it seems like original research and/or unsourced material. (Let me know if this is incorrect some way, I didn't see anything here about it. --Suamme1 18:04, 27 March 2007 (UTC)
- Yes. If not on that ground, then on grounds of sloppy language, incongruous placement within the article, and placement in the incorrect article. I should have killed it earlier myself. Welcome to the Wikipedia vigilantes. It's not the most fun job in building the encyclopedia, but it's a necessary one.
- Let me make it a bit clearer. External linked sites don't have to conform to the same standards of neutrality, etc of articles. Links may for example go to the personal or official sites of controversial persons, corporations or organizations that may be concerned with promoting and defending their products, views or selves, rather than with balance or reliable sourcing. This idea obviously necessitates judgement calls, and I figure you made the right judgement here. Sometimes a look at other edits by the same account can help understand where they are coming from. Jim.henderson 20:55, 27 March 2007 (UTC)
