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#61
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If Superheterodyne, why not Subheterodyne?
"Highland Ham" ** Whoopeee !!!! Another totally anencephalic, radio ham wack-job opens his dumb gob. "Eeysore the ****ing LIAR " Supersonic today means travelling faster than the speed of sound. ** Not when the context is frequency - you ****ing MORON. http://en.wiktionary.org/wiki/supersonic ============================================= Phil , ** Never address me personally via any NG - you pig ignorant ****. It will be a relief to all (civilised) users of this NG ** Leaves all self appointed, net cop ****s like you out - don't it ??? Frank GM0CSZ / KN6WH ** **** the hell off - Frank. IMO, radio hams are the scum of the earth. Go stick your stupid, smug opinions straight up your FAT ARSE. ....... Phil |
#62
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If Superheterodyne, why not Subheterodyne?
Highland Ham wrote: Phil Allison wrote: "Eeysore the ****ing LIAR " Supersonic today means travelling faster than the speed of sound. ** Not when the context is frequency - you ****ing MORON. http://en.wiktionary.org/wiki/supersonic ....... Phil ============================================= Phil ,It will be a relief to all (civilised) users of this NG ,if you would discharge your life's frustrations onto another more appropriate NG. It is clear ,to me at least ,that you need help. Killfile him, for your own sanity. -- You can't have a sense of humor, if you have no sense! |
#63
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If Superheterodyne, why not Subheterodyne?
On Tue, 21 Apr 2009 05:34:25 -0700 (PDT), Tim Shoppa
wrote: On Apr 21, 1:05*am, "Phil Allison" wrote: "AF6AY" Everyone ought to realize that "Wikipedia" data can be written by ANYONE ** As are NG posts. The difference being that Wikis are full of checkable references and are subject to on-going correction. The best Wikipedia articles are often filled with good checkable references, but other times it sounds like they were written in a foreign language and translated into English and have few (if any) good references. Just because a Wikipedia entry isn't well-written or sounds awkward doesn't mean it's wrong, but I will often reject what I don't like in the poorly written ones. Somewhere there's a bunch of people who spend their time correcting and improving Wikipedia entries, and I think overall they are doing a good job, but that doesn't mean the result is always devoted to my interests. Just like anything else in this world, it's got workers and it's got managers and they aren't always devoting their attention to the little corners of arcania that I live in. It's not that the Encyclopedia Britannica is perfect either. I can open it up to the very few subjects that I happen to be expert on and find over-simplifications and a lack of cites to what I consider to be the best references. That doesn't mean it's out-and-out wrong, just that it's an Encyclopedia, and by definition they can't do anything but touch on the surface of all the interesting stuff in the world. Of course in academia I got real used to opening a journal and instead of reading the articles, to go straight to the references and see if they are quoting one of my articles :-). Breadth vs specialization, can't pick them both. Tim. Just the same, i try. perhaps my approach can be better described as having adequate coverage at adequate depth. Or sort of turning thinge sideways and trying to get best area with a very complex shape with many largish estensions in some areas and virtually none in other places. Knowledge is kind of fractal any way. |
#64
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If Superheterodyne, why not Subheterodyne?
On Thu, 23 Apr 2009 11:27:37 -0400, Phil Hobbs
wrote: John Larkin wrote: On Mon, 20 Apr 2009 09:50:05 -0700 (PDT), Tim Shoppa wrote: A terminology question I suppose about the derivation of the term "Superheterodyne" more than anything else: Does the "Super" actually mean anything? Is there a Subheterodyne? Traditionally superhets mix a higher radio frequency down to a lower IF frequency, but certainly in the past few decades radios with IF's above the RF frequency have become very common in broadband applications, and those are still called superhets, not subhets :-). Google turns up a couple hits on subheterodyne but other than one that might mean "IF higher in frequency than RF" I don't recognize what they mean.. I suspect that "Super" was more a marketing term than anything else :-). Tim N3QE Supersonic. http://en.wikipedia.org/wiki/Superheterodyne_receiver John Not a bad article, except that he seems to think that cascading multiple stages at a single IF improves image rejection, and that very high IFs are much less common than double conversion. (Does *anyone* use double conversion anymore? Spur city.) Double conversion may be thought to be passe an awful lot of sattelite TV receivers are double conversion or triple conversion. Think LNB. |
#65
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If Superheterodyne, why not Subheterodyne?
John Larkin wrote: On Mon, 20 Apr 2009 13:57:26 -0700 (PDT), Tim Shoppa wrote: On Apr 20, 3:44 pm, John Larkin wrote: On Mon, 20 Apr 2009 12:23:53 -0700 (PDT), Tim Shoppa wrote: On Apr 20, 1:10 pm, John Larkin wrote: http://en.wikipedia.org/wiki/Superheterodyne_receiver I saw that in Wikipedia too. I didn't believe it, it doesn't make sense. Why not just call all radio frequencies and IF frequencies above 20kHz "supersonic"? Then all radios (*) are supersonic, and we're back to super meaning nothing at all. Possibly because heterodyne receivers mixed to sonic frequencies. I didn't really trust Wikipedia on this (it uses unusual language to talk about perfectly conventional subjects) but I did find my December 1922 QST, and it says (page 11): In December, 1919, Major E. H. Armstrong gave publicity to an indirect method of obtaining short-wave amplification, called the Super- Heterodyne. The idea is to reduce the incoming frequency which may be, say 1,500,000 cycles (200 meters), to some suitable super-audible frequency which can be amplified efficiently, then passing this current through a radio frequency amplifier and finally rectifying and carrying on to one or two stages of audio frequency amplification. To me that sounds a little less awkward and more natural than the derivation that Wikipedia tries to draw. Tim N3QE I did like the wiki bit about people using hundred-tube TRF receivers. And the claim that a TRF receiver was simpler to use than a super–heterodyne. It makes you wonder if the author even knows how a TRF receiver works. Most had a separate knob per tuned circuit, since the attempts at gear driven tuners didn't track very well. -- You can't have a sense of humor, if you have no sense! |
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