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#1
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Paul W. Schleck " wrote:
Transmitting 50 kilowatts from a single site capable of covering most of North America, using groundwave propagation, independent of solar activity, is an "outrageously inefficient way to distribute a small quantity of information?" Well, I do hope that you are hurrying to write your Congressman to demand that the National Institute of Standards and Technology put an immediate end to this grave outrage, and profound waste of taxpayer's money that has been going on for decades. After all, what does the NIST know about technology, or useful communications? Perhaps as little as the engineers and marketers in the economically successful and useful product field of WWVB watches and clocks, in your estimation. Wouldn't it make more sense to include WWV and WWVH along with WWVB? Are you familiar with the Internet-based ntp system? Then, there is the matter of GPS, which has a time capability that is incidental to its navigation function. [...] I think you are underestimating the power of SMS. As for the comparison to E-mail, I don't have to ask, as journalists have already done so, including this recent article from Slate: http://www.slate.com/id/2177969/pagenum/all/ Simply put, young people find appeal in the immediacy of small, but low-latency messages sent in relatively large numbers over a long period of time, and the information transmitted is far more rich and meaningful that what you imply above. In many respects, this type of communication is not stilted or limited, but almost provides the immediacy of a conversation, without having to run up your voice minute charges or leave your other callers unable to reach you due to the long-term busy signal. Young people do still use E-mail, but in circumstances for which it is the better choice. They are not seeking some overall best "general purpose communications" to get their messages across to each other. I don't see anything in that that contradicts my statement that SMS is mainly used for messages of little importance. It is also called CMS, for casual messaging service. I didn't realize that only "general purpose communications" were considered worthwhile. A multi-purpose system that can match a single-purpose system on the performance of the objectives of the single-purpose system is generally, if not universally, considered superior. Your previous reply argued that it was undesirable to use such a low-speed technology as Morse code given that there were many higher-speed alternatives (faster by "orders of magnitude" you said). I replied to you that fastest is not always best. Other issues (previously enumerated by me) might actually dictate the choice of lower-speed communications as the best choice. I also don't see "general purpose communications" mentioned in Part 97. Many "single purpose, dedicated systems" are used by amateurs, and help fulfill amateur radio's Basis and Purpose. In many cases, a "single purpose" technology is far more useful than a misfit, one-size-fits-all, "general purpose" one. Before we make too many assumptions about an undefined term, perhaps you can describe what types of "general purpose communications" you would consider to be worthy goals for the Amateur Radio Service, and which "single purpose" technologies you would like to see eliminated? Why do you want me to reinvent the wheel? Lets go to the source (condensed from Part 97.1): * emergency communications * contribute to the advancement of the radio art * advancing skills in both the communication and technical phases of the art * expansion of the existing reservoir within the amateur radio service of trained operators, technicians, and electronics experts * continuation and extension of the amateurs unique ability to enhance international goodwill Would you also kindly define what is a "single axis of data," in terms familiar to those involved in communications engineering and technology? A single quantity, like time or location What, then, would be "multiple axes of data?" Two or more simultaneous quantities, like time AND location or course AND speed. So, in other words, you are actually agreeing with my previous reply to you that there are many useful Morse code based communications technologies that do not actually require memorized, in-head, copy of Morse code. I'm glad that we agree on something. There is probably no purpose for which Morse can be used as a machine language where there isn't a choice of other, better suited languages available. This includes aeronautical beacons. You are grasping at straws, now. Wow, these curmudgeons must have been very powerful and effective in their obstructionism if they undermined entire areas of communications technology development in this country over the last 30-40 years. I didn't realize that our national technology infrastructure was so inflexible and lethargic that it could not recover from these influences, even after so many decades. When you look at the development of the Internet, Linux and other free software, you have to wonder about the infrastructure behind it. How did it come about? There was no regulatory body. There were no licenses. There were no "Elmers." Until recently, there wasn't even any formal schooling available, except on the sort of machinery that existed only within the Fortune 500. Early Internet users and developers had to read O'Reilly books and figure it out on their own. That showed great initiative. It demonstrated the sort of determined, driven advancement of technology that was once seen in amateur radio. But that sort of thing has passed ham radio by. It has been a long time since ham radio was a source of innovation. I blame the Morse cultists who hijacked amateur radio for use as their personal playground. Just the introduction to your previous article, where you directly compare the Baud rate of Morse code with that of "obsolete" telephone modems. You stated that their data rates differed by "orders of magnitude," implying that communications technologies that were "orders of magnitude" slower than telephone modems could be dismissed as obsolete. An amusing interpretation. It follows that trains and ships should be discarded because they are much slower than airplanes. Following the natural extension of that argument, then the only technologies that could be favorably compared to such telephone modems, and meet your argued standard of non-obsolete, could only be realized on high VHF and up. As I argued previously, use and advocacy of Morse code has no bearing on the current deployment of such technologies, as no Morse code test has been required to access them for at least 17 years. The Technician-class license has existed for far longer, and has only a minimal Morse code examination. You left out the faster mode of communication known as "voice." It is widely used on HF. Further, I once looked at a band plan that showed how DV could be used on HF. They described a system of HF DV that took up just slightly more bandwidth than SSB and substantially less than AM. So, to summarize: slow-speed (less than 100 baud) PSK31 : "Good" similar order-of-magnitude speed Morse code: "Bad" So, it's not the speed you object to, it's the use of Morse code? Couldn't you have just stated that, and not gone to the trouble of bringing in other arguments like speed and bandwidth, or whether a communications technology is sufficiently "general purpose" or not, regardless of whether something "general purpose" would be the best choice in a given circumstance? Just say that you don't like Morse code. Others would at least give you credit for honesty. Who are these "others" and when did they appoint you as their spokesman? References please? A Google search returns no evidence that Navy stations like NAA in Cutler, Maine have gone off-line. Are you possibly thinking of their ELF experiments that were recently ended? Even if so, what competing technology is the Navy contemplating that will reliably contact our submarine fleet that has "gone deep" under many fathoms of RF-attenuating sea water? I am thinking of the site in the Upper Peninsula of Michigan and the increased reliance on TACAMO aircraft (at the time of the shutdown). I also didn't realize that amateur radio had similar "networks" that would need to be shut down. The infrastructure that is being wasted on Morse includes band segments that have, until recently, been reserved for its exclusive use. I am very glad to see that almost all CW segments now allow data modes (50-50.1 and 144-144.1 being the only exceptions). There is also the inclusion of keyer provisions in HF radios. It will be interesting to see what the marketplace does to code tapes and code keys. I don't think they will last long. While Morse supporters often point to treaties, the fact is that the US was one of the last countries to abandon the Morse requirement for an HF license. Other countries began dropping that requirement many years earlier, while still claiming to be in compliance with their treaty obligations. How do you explain that? To me, it sounds like the FCC used the treaties as a pretext to keep the code requirement in order to placate the ARRL and the Morse zealots. Looked pretty coherent to me, but for your benefit, I'll dissect it in detail: "If you are saying that someone *else* should have developed these technologies ..." In other words, amateur radio has failed to meet some standard of technology development. Other people were somehow "wasting" their time doing other things. "... (other than you, of course) ..." What have you done to make amateur radio a better place? Have you written your Congressman? Petitioned the FCC? Worked in the communications engineering and technology field? Developed amateur radio software and hardware solutions? You seem to be knowledgeable on many technical subjects, including the history of that technology over many decades. Did you try to change things, or are you asserting that you did not have the skills or abilities to help do so, even working with others over many decades? I have worked in the electronics industry. I have made my views clear to any and all who had an interest in the subject. I made those views as clear then as I have done in this newsgroup. "... and since they haven't, then someone *must* be blamed, ..." I was implying that you were seeking scapegoats, as it is easier to blame others than look in the mirror. "... well, you can't really dictate how the world should turn out without taking an active role to help make it that way." In other words, Lead, Follow, or Get Out of the Way. "Sidewalk Superintendents" have very little influence on society. What is your choice? Also, some people seem to confuse actual solutions to problems (whether in amateur radio, or on the newsgroups) with a contest over who can become the most "outraged." To quote Jim Kelley, AC6XG: "Outrage, and a buck-fifty, will get us exactly what?" -- Klystron |
#2
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On Sun, 23 Mar 2008 22:53:54 EDT, Klystron wrote:
Wouldn't it make more sense to include WWV and WWVH along with WWVB? Are you familiar with the Internet-based ntp system? Then, there is the matter of GPS, which has a time capability that is incidental to its navigation function. Want some fun? Compare the time ticks received from WWVB, WWV, NIST-on-line, and GPS. What, they are not all simultaneous? Welcome to the real world. GPS time does not correlate with UTC by any means (several seconds difference). In one of the first digital military command and control system that I was involved in during the early 1960s, we used rubidium standards at our switching centers to get accurate time synchronization, and even then it was rather crude because the line delays varied so much. HF propagation (WWV/WWVH) is even worse in that regard. -- 73 de K2ASP - Phil Kane From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon e-mail: k2asp [at] arrl [dot] net |
#3
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On Mar 23, 8:29�pm, Phil Kane wrote:
On Sun, 23 Mar 2008 22:53:54 EDT, Klystron wrote: � Wouldn't it make more sense to include WWV and WWVH along with WWVB? Are you familiar with the Internet-based ntp system? Then, there is the matter of GPS, which has a time capability that is incidental to its navigation function. Want some fun? �Compare the time ticks received from �WWVB , WWV, NIST-on-line, and GPS. �What, they are not all simultaneous? ï ¿½Welcome to the real world. �GPS time does not correlate with UTC by any me ans (several seconds difference). In one of the first digital military command and control system that I was involved in during the early 1960s, we used rubidium standards at our switching centers to get accurate time synchronization, and even then it was rather crude because the line delays varied so much. � HF propagation (WWV/WWVH) is even worse in that regard. I've compared each of our three radio-set clocks at this residence (in Los Angeles) and find excellent correlation between their one-second changes and both WWV and WWVH. Don't have any GPS receiver to try the same. In 1960, while working in the Standards Lab of Ramo-Wooldridge Corp. in Canoga Park, CA, I got to pull some OT on Saturdays to measure the difference between east coast transmissions of WWV and the local General Radio frequency standard. Just a plain old quartz crystal standard oscillator driving divider chains to the built-in clock. I would record the microseconds of difference between local clock ticks and WWV ticks from the east coast. Not much variation in a week's time, don't remember just how much (it was 48 years ago). Yes, propagation on HF does vary but it is sometimes exaggerated. Before R-W went into a business tailspin, the Standards Lab was ready to get a low-frequency HP receiver for 20 KHz to improve on establishing a local, secondary frequency standard. No joy on that corporation which was eventually sold off. All I ever got to see was the 'diurnal shift' of 20 KHz phase recordings at sunrise and sunset. :-) 73, Len AF6AY |
#4
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On Mon, 24 Mar 2008 00:09:24 EDT, AF6AY wrote:
In 1960, while working in the Standards Lab of Ramo-Wooldridge Corp. in Canoga Park, CA, Errrr, Len, the Ramo-Wooldridge Corporation went out of existence in 1958 when it merged with Thompson Products to become Thompson Ramo Wooldridge, Inc. Remember that I started with the "original" R-W in 1957 and was employed by them at the time of the merger at the former El Segundo Boulevard facilities (I never did get to work at the Arbor Vitae Street facilities which were the headquarters of the Air Force Ballistic Missile Division). They didn't move to Canoga Park until the late fall of 1959, and I was laid off (for the second time) in June of 1960. Thompson Ramo Wooldridge, Inc - later TRW, Inc. - went on an acquisitions binge and itself went out of existence in 2002 when the electronics and aerospace parts were acquired by Grumman (now Northrop Grumman) and the automotive parts mostly by Goodyear. In context - RW was always friendly to ham radio, and the pre-merger RW Corp. actually let us scrounge both new and recycled parts for ham rigs and audio projects which became our property as long as we signed a register/release stating what we were building. I got to pull some OT on Saturdays to measure the difference between east coast transmissions of WWV and the local General Radio frequency standard. Just a plain old quartz crystal standard oscillator driving divider chains to the built-in clock. While at the El Segundo Blvd. facility we had a project of measuring distance to a transmitter using the time delay of HF transmissions received at different sites with a calibrated link between them (azimuth was easy using standard DF techniques) and we used the GR frequency standard referenced above. Using WWV was too error-prone. I would record the microseconds of difference between local clock ticks and WWV ticks from the east coast. Not much variation in a week's time, don't remember just how much (it was 48 years ago). My references about time differences, BTW, was to the time of day, i.e the time of the tick, not the interval between the ticks. GPS has a very noticeable offset compared to NIST. I guess that it's only nuts like me that care about that. My early training as a broadcast studio engineer while I was in engineering school required timing of program starts and endings to the second. "Dead air" was not permitted. Three o'clock did not mean three o'clock plus 1 second - the Western Union clock reset pulse on the hour was broadcast as a "beep". From my other hobby, "railroad accuracy" of watches (which are compared with a master clock at the start of a shift) requires one second per day, 30 seconds per month. Easy to do with quartz watches nowadays. There even used to be a SP Railroad dial-up number (now long gone) where the "time man" would announce the time "Southern Pacific Standard Time is ...." as contrasted to Ma Bell's "time lady" who would announce "Pacific Standard Time is ..." -- 73 de K2ASP - Phil Kane From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon e-mail: k2asp [at] arrl [dot] net |
#5
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Phil Kane wrote:
On Sun, 23 Mar 2008 22:53:54 EDT, Klystron wrote: Wouldn't it make more sense to include WWV and WWVH along with WWVB? Are you familiar with the Internet-based ntp system? Then, there is the matter of GPS, which has a time capability that is incidental to its navigation function. Want some fun? Compare the time ticks received from WWVB, WWV, NIST-on-line, and GPS. What, they are not all simultaneous? Welcome to the real world. GPS time does not correlate with UTC by any means (several seconds difference). Each GPS sattelite has it's own on board atomic clock and the system can easily provide UTC with accuracy on the few microseconds level with an ultimate limit of +/- 340 nanoseconds using an appropriate receiver and hardware. GPS is the basis for most of the current NTP time servers. http://www.ntp-time-server.com/gps-t...ime-server.htm -- Jim Pennino Remove .spam.sux to reply. |
#6
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#7
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Phil Kane wrote:
Something must have changed (or been fixed) then - we made measurements about three years ago and there was about six seconds offset - an eternity for accurate time measurements. 340 nanoseconds we can tolerate. Six seconds we can't. Could "selective availability" have anything to do with that? -- Klystron |
#8
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In article ,
Klystron wrote: Phil Kane wrote: Something must have changed (or been fixed) then - we made measurements about three years ago and there was about six seconds offset - an eternity for accurate time measurements. 340 nanoseconds we can tolerate. Six seconds we can't. Could "selective availability" have anything to do with that? No. |
#9
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Klystron wrote:
Phil Kane wrote: Something must have changed (or been fixed) then - we made measurements about three years ago and there was about six seconds offset - an eternity for accurate time measurements. 340 nanoseconds we can tolerate. Six seconds we can't. Could "selective availability" have anything to do with that? It was turned off about 7 years ago and even then just put the ultimate accuracy in the low microsecond range. GPS has never been off by six seconds. -- Jim Pennino Remove .spam.sux to reply. |
#10
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In article ,
Phil Kane wrote: Something must have changed (or been fixed) then - we made measurements about three years ago and there was about six seconds offset - an eternity for accurate time measurements. 340 nanoseconds we can tolerate. Six seconds we can't. It's changed. GPS and UTC now differ by 14 seconds, according to http://tycho.usno.navy.mil/gpstt.html. This is because GPS time does not include leap seconds. This 14 second difference is part of the GPS broadcast, so can easily be backed out of the GPS time data to produce UTC. Once corrected, the UTC values have the stated accuracy. Don't be confused by the latency of some GPS units in producing time/fix products. I've seen them produce fixes several seconds later. That's why the time is included in postition data, so you know when you were there. If you want time from your GPS, you need either the 1PPS pulse output or a unit with a known and predictable period from real time to character output. For many uses, simply assuming that the first character of the output string (NMEA) occurs at the time in the message is adequate, but that's not going to get you your 340ns accuracy. For example, I am using a Trimble Acutime to feed an home-brew time demon. Tests comparing system time from this demon to ntp stratum 1 servers gave a few millisecond difference. Good enough for me. |
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