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#91
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"Dick Carroll;" wrote:
Floyd Davidson wrote: So while it is quite possible to make the s/n ratio larger by increasing the signal, it is equally possible, and sometimes much better to increase the s/n ratio by lowering the noise. Sometimes it is the *only* option available. However, what has to change is the noise power per Hz, and reducing the bandwidth does not change that. That *Can't* be correct for all cases. The total noise appearing in the channel is the sum of that appearing in every Hz within the entire channel. A narrow signal such as a radiotelegraph signal may not occupy the entire width of the channel. So narrowing the channel width DOES reduce the noise while preserving the signal and improving the SNR.. Obviously where the signal is as wide as the channel this doesn't work, but in ham radio, working CW it sure does. Guaranteed. DICK, you are not discussing the efficiency of a mode. What you are arguing is the *operator's* ability to effectively use a mode. Yet you insist that you are proving something about the mode itself, rather than the operator and his equipment. If the operator is effectively utilizing the mode he has chosen, the bandwidth requirement of the mode is closely matched to the channel the operator provides. You are saying that your ineffective use of one mode compared to your more effective use of another mode proves that it was the *mode* that was more effective. All you've done is demonstrate that you don't understand the effective use of radio communications, the theory behind efficient use of the modes involved, or what you have observed. Increasing the signal power has the desired effect. There are other ways to accomplish that, of course. Reduction of noise by any means other than reducing the bandwidth (switching from an omni directional antenna to a directional antenna, for example) will have the desired effect. Another example of why his stuff doesn't apply to the real world of ham radio. When a ham is working another station he has no control over the power that station is injecting into the channel. What he can control is the bandwidth,within limits of course. DICK, the operator can do any number of things. We should assume that just for starters the receive operator is correctly adjusting the bandwidth of the channel to match the bandwidth being transmitted. There are *many* other things that can be controlled to change the effective use of a communications channel. Your suggestion *reduces* the channel capacity rather than making it more effective. If you want more *effective* communications, either increase the data rate within the existing channel, or if it is already being used as best that a given mode can provide, increasing the channel capacity to either 1) allow a higher data rate or 2) reduce the error rate. To increase the channel capacity an operator has several choices. Asking the distant end to increase power is one possible solution. Another is to use, or adjust, an antenna to provide an increase SNR, whether by reducing noise or by increasing the signal, or both. Within ham radio such situations vary widely, but for CW the sitiation is pretty well straightforward. Hams almost always enhance CW signals by reducing the bandwidth which raises the SNR. Only if it was misadjusted to begin with. You aren't making a case for CW, you're making a case that you are a poor operator. -- Floyd L. Davidson http://web.newsguy.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#93
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"Dick Carroll;" wrote:
That's a *very* hollow laugh, Carl. Efficiency goes way beyond anything Shannon ever described. You should know that. The word applies to far more than just what goes on within any single "channel". But you choose to ignore every bit of it save what Shannon had to say. I find that very revealing- An Information Theory fixation! I just realized---You're a Shannonist!!!! Everyone who uses a telephone, a CD player, any form of digital communications on the ham bands, a digital computer, and or many many other things... is indeed a Shannonist. The theory of communications that he set forth *is* that all pervasive. -- Floyd L. Davidson http://web.newsguy.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#94
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"Dick Carroll;" wrote:
Floyd Davidson wrote: DICK, you are not discussing the efficiency of a mode. What you are arguing is the *operator's* ability to effectively use a mode. Gasp! Floyd, are you *finally* beginning to understand what ham radio is all about???? DICK, I've known for decades that there are hams as dumb as you! NO, Frostbite, what you've done is desmonstrate that you know virtually nothing about anything except Shannon. I happen to ALSO know how it is with ham radio! Yeah, we can tell! There are *many* other things that can be controlled to change the effective use of a communications channel. Your suggestion *reduces* the channel capacity rather than making it more effective. FLOYD, FLOYD , FLOYD!!!!! One more time----- **IN HAM RADIO WE VIRTUALLY ///NEVER/// NEED TO EMPLOY MAXIMUM CHANNEL THROUGHPUT/DATA RATE!!!*** DICK, DICK, DICK, no **** DICK. Because Shannon says that you *can't* use it. Do tell. And you actuall suppose that I and by extension most other hams don't know this? If you know anything at all DICK, it is impossible to determine so from the posts you make on Usenet. You're nuts. AND have zero experience as a ham. My experience as a ham is probably more than yours. -- Floyd L. Davidson http://web.newsguy.com/floyd_davidson Ukpeagvik (Barrow, Alaska) |
#95
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![]() "Floyd Davidson" wrote in message ... "Shannon had written "a blueprint for the digital age," says MIT information theorist Robert Gallager, who is still awed by the 1948 paper." http://www.kjist.ac.kr/~slic/est/cshannon.pdf That's probably why Dick is so anti-Shannon and continually denies that Shannon's work has anything to do with ham radio ... Dick is scared to death that modern digital communications (that he obviously isn't capable of comprehending) will ultimately supplant his beloved Morse ... which appears to be the only thing in ham radio at which he can claim true proficiency. Simple version: Dick can't face the fact that his only "claim to fame" (as in "a legend in his own mind") is irrelevant except as a recreational activity. (NOTE: I have no problem with folks pursuing Morse as a recreational activity ... what I have a problem with is their insistence that it's "essential" to be a "Real Ham" and that a pass/fail proficiency test should forever remain a "gatekeeper" to the HF bands. Carl - wk3c |
#96
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Floyd Davidson wrote:
Mike Coslo wrote: some snippage Ohh, I just got that pejorative from someone here. I kind of like it tho'. I'm still playing Hockey at my ripe old age, and will as long as I can. What? You think that is a perjorative???? You, sir, are no *real* hockey puck! Oh, I don't think it is. but the gentleman saying it does. Heh, years ago I can remember going to a hockey game in Fairbanks, when the house was full, with hardly a seat left. Not a big deal, except that there were *four* hockey games going that night, and *all* of them were playing to a full house. Something like 1/4 the population of Fairbanks was taking in a hockey game that night. Now that sounds like a real blast! And I do like to get up to Canada whenever I can. Here in Alaska we tend to like our neighbors... and agree with them about folks in the Lower-48 being strange, eh! You betchya! - Mike KB3EIA - |
#97
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Subject: NCVEC Position on Code
From: Floyd Davidson Date: 8/11/03 3:22 PM Eastern Daylight Time Message-id: "Dick Carroll;" wrote: Floyd Davidson wrote: The problem is you are comparing two different data rates through the same channel. PSK-31 runs at 31.5 bits per second. If you used CW at that rate, it works out to about 37.8 wpm. Are you telling me *you* can copy 35 wpm using a 200 Hz filter when there is Doppler distortion from auroral activity? Can you, Floyd? No, you idiot- do you come from the same village as Burke?- What I said is that we REAL HAMS have no NEED to invoke laboratory nonsense to interfere with our on the air operation! ANd they are NOT THROUGH THE SAME 31 cycle channel! They both come through the channel tha *I* set, not Shannon, which was a 2.4 kc channel which is modifiable by all those snazzy IF Sounds as if you, like Larry Roll, don't want to have anything to do with any of that "Empirical Theory" stuff of his, eh? Perhaps I remembered the previous discussion incorrectly? Were you using a 2.4 KHz channel, or a 200 Hz channel? In either case the agc, and hence SNR, are affected by the noise in that channel, not the 30Hz filter in DSP software. Only if the AGC was turned on. In many situations, reception can be improved by disabling the AGC. Old CW operator's trick. But once again, Shannon *does* apply to everything you've got there. *If* you want to actually understand it, that is the *only* way to explain it. Shannon's work sets a limit. Real world performance cannot be "better" than Shannon predicts. But it can be worse. Or you can continue to be a glorified CB operator. Have you ever actually used PSK-31, Floyd? In fact, what you've done is demonstrate that Shannon's work *does* apply to ham radio! PSK-31 is an m-ary channel using QPSK (where m = 4), which trades signal to noise ratio for bandwidth to obtain the same data rate as it would using straight phase modulation. Which is good in some situations and not so good in others. What *you* should be saying is that your experience demonstrates that Shannon's theories prove true in the practical application of ham radio. When the SNR is low, CW can be useful, albeit at very low data rates, if restricted bandwidth is a requirement. Of course, if the bandwidth wasn't restricted to 200 Hz, almost any variation on PSK modulation would out run CW for efficiency, as can easily be demonstrated using Shannon's formula. That depends on how "efficiency" is defined, doesn't it? If we count the power required to operate the radio and the power required to operate the laptop, PSK-31 isn't that "efficient".... Yeah, Frosty, most of us know all that, it's been well published, and quoted here for some time. But it still has no applicability to ham radio outside the theoretical. Apparently your Empirical Theory is a little sparse there DICK. Why and how do you think PSK-31 was invented to begin with? I happen to know the answer to that question. The inventor and his helpers were interested in a very narrow bandwidth "keyboard to keyboard" mode to replace Baudot RTTY. It clearly does have practical benefits, and when you attempted to use PSK-31 you *were* making use of those benefits. Of course. OOK CW has benefits, too. Yet it seems to bother some people to admit that. It is interesting to note that Larry Roll and Dick Carroll have actual experience with PSK-31, while Brian Burke, Floyd Davidson and Len Anderson have none. Yet the latter insist upon denying the experience of the former. And vice versa. Why not just use the mode you like best and have fun? If PSK-31 is so wonderful, why is it that only two of the five named have actually used it? |
#98
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Len Over 21 wrote:
Tsk, tsk, tsk...how quickly they forget. You claimed to be in the "upper percentile of amateur radio." :-) I would classify you as little more than an ego-driven salesman type who does CB-like radio activity with a federal license grant. Aren't you supposed to be in the national pool of "trained communicators" for the nation's benefit and "advancing the state of the art" of AMATEURISM? I liked it better when you were just a Soma Come Loud student who could get any human resources job he wanted after graduation. From Leonard H. Anderson: "YOU have NO authority to call anyone anything, demean them, make fun of them, or anything else...yet YOU continue to do so. That indicates the perversity of your control-freak psychosis." This one is starting to come in handy already. Thanks, Len. Dave K8MN |
#99
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"Larry Roll K3LT" wrote in message
... In article , Floyd Davidson writes: Floyd: Please, enlighten us. Provide a definition of the term "empirical." Your term was "Empirical Theory". Why don't *you* try to define that in terms of "empirical" and "theory". In theory at least, we should be able to empirically determine that Larry is not theorist about empiricism, but rather an empiricist. empiricist, n. -- a quack Floyd: I request meaningful participation in the debate, you respond with more name calling. Following your lead, no doubt. If I made some sort of faux pas in the use of the term "empirical theory," anyone interested in maintaining a useful discussion of the issues would have simply corrected the error, and let it go. Whine, whine, whine. You reap what you sow, Larry. However, it seems as though I've merely armed you with a straw to grasp, to be utilized whenever you can't be bothered to continue to contribute rational, logical arguments. Pot/Kettle. Since you've obviously abandoned the notion of reasoned discourse, you automatically lose. You're out of your league here, Floyd. Just like your colleague, Lennie. 73 de Larry, K3LT Pah!! You gotta be kidding. You're out on a league of one, Larry. Save for Dick, I see no one in your court. I, at least, see occasional posts in good standing from nearly everyone...gosh, except for you and Dick... Kim W5TIT |
#100
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