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#21
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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. |
#22
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On Mar 18, 7:44�am, Klystron wrote:
� �I am trying to convert "words per minute" into "bits pe r second." Bits per second, in turn, is APPROXIMATELY equal to baud, a common measure of modem (or other means of data transmission) speed. I need to quantify one factor: How many letters are in a "word?" If we assume that there are 5 (five) letters to a word, my calculations look like this: It has been common convention in wireline telegraphy to count "one word" as having 5 characters followed by a space. The origin of that seems to be that it was most advantageous for humans to use/remember while using the Commercial Codes, a form of encipherment both to protect information and to reduce the number of words in a telegram. Bentley's Commercial Code seems to have been the most used with 17 editions, publishing Code Books for any business or government. As a result of those Commercial Codes, actual cryptographic codes also used 5 characters followed by a space, hence the term '5-letter groups' in referring to a "word." By the time of WWII starting, the cryptographic systems were more advanced and it was not possible to tell one 'word' from another but it was common practice to send encrypted text as 5-letter (or character) groups; the actual space in clear text was determined by the null or space substitute in poly- alphabetic rolling-key encryption codes. (reference: M-209 Code Converter used in the field in Europe by US forces) 73, Len AF6AY |
#23
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 In Klystron writes: Paul W. Schleck " wrote: [...] 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 Perhaps I should clarify. When I asked the above question, I meant specific technologies and examples of communications systems, not a restatement of the general strategies of the Amateur Radio Service that are enshrined in its Basis and Purpose. The Basis and Purpose enumerates high-level goals, but does not specify the implementation details, including the specific technologies. I'm sure that we are all familiar with FCC Part 97.1, and restating it really wasn't the answer that I was looking for. Could you please be more specific? - -- 73, Paul W. Schleck, K3FU http://www.novia.net/~pschleck/ Finger for PGP Public Key -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (SunOS) iD8DBQFH5zR26Pj0az779o4RAiqtAJ4003CD5KS18L4Ybt5bL//NfZKBFwCfV9Qg 9eRBs7HEqZzaMPPaM3IC4QY= =UFaB -----END PGP SIGNATURE----- |
#24
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-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 In AF6AY writes: According to this recent demonstration on the Tonight Show with Jay Leno: http://www.youtube.com/watch?v=AhsSgcsTMd4 Ahem...quibble mode on...that little bit on the Tonight Show was a 'setup' gig that employed two young local male actors as the (described) "text messaging experts" but the two hams (one of which would very soon become marketing director for Heil Sound) were real. That is the input I got directly from a reliable staffer on the Tonight Show. Took a few phone calls to get that information but it is an advantage of living inside the entertainment capital of the USA (aka Los Angeles, CA)...and the NBC western Hq is only about 5 miles south of my place, down Hollywood Way to Alameda and then east about a mile. That whole bit was really a send-up on the popular fad of text messaging done by teeners and young adults. That bit is about as 'real documentary' as Leno's send-ups on the 'street interviews' with ordinary (apparently clueless) younger folk on various kinds of knowledge. In short, ONLY for gag purposes. [...] Sorry, but I've got to call baloney on this one. The individual who appeared on the Tonight Show who sent the text message was actually Ben Cook, and not an actor. Ben held the world's record for fastest text messaging: http://en.wikipedia.org/wiki/Ben_Cook The two Morse code operators, Chip Margelli, K7JA, and Ken Miller, K6CTW, have attested to this being an actual contest with an actual, previously unknown, message to send, which was sent both by Morse code, and by text messaging. And there's no disputing that fast Morse code would always beat an SMS text message of the same length. See: http://www.arrl.org/news/stories/2005/05/16/3/?nc=1 Two named witnesses would appear to trump one anonymous source. Therefore, your anonymous "reliable staffer" seems anything but. - -- 73, Paul W. Schleck, K3FU http://www.novia.net/~pschleck/ Finger for PGP Public Key -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (SunOS) iD8DBQFH5zJI6Pj0az779o4RAn+5AJ9ffyD9Wq/klqCmx9PlvGnKFKjYLwCeKjlV Q9BjLTsT7hM/Hb6FRO7X4D4= =ChL0 -----END PGP SIGNATURE----- |
#25
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On Mar 23, 9:53�pm, Klystron wrote:
�Paul W. Schleck " wrote: � �Wouldn't it make more sense to include WWV and WWVH along with WWVB? WWV and WWVB transmitters are at the same site in Fort Collins, CO. I was there. Are you familiar with the Internet-based ntp system? Such a system requires connectivity to the internet. WWVB does not; just requires a receiver. Then, there is the matter of GPS, which has a time capability that is incidental to its navigation function. GPS can only be used where the satellites can be "seen" by the receiver. The WWV system still has its uses. I suspect its cost is trivial compared to other systems, too. 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 loca tion or course AND speed. The WWV system isn't just about time. The transmitters are also frequency standards. That's two axes of data. For those of us who use HF, they are also propagation beacons - that's three axes. There are also voice geomagnetic announcements - that's four axes. 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. Yes, there is: Any application where the sender or listener may be a human rather than a machine, and where an interface like a keyboard/screen isn't practical. 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. Actually there was and is. "The internet" as we know it could not exist without certain legislation that made it possible, and a huge commercial investment of communications infrastructure to support it. What we call "the internet" developed from ARPANET, which was a DoD thing, just like GPS. Swords into plowshares and all that. There were no licenses. There were no "Elmers." Actually, there were, just not in the same form as in radio. The licenses were regulations; the Elmers were people who developed easier-to-use systems. 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. How do you define "recently"? I got started online in 1997, and "the internet" had only been publicly available for a few years at that point. That showed great initiative. It demonstrated the sort of determined, driven advancement of technology that was once seen in amateur radio. The internet was and is a commercial enterprise. Amateur radio was never such an enterprise, by its very nature. But that sort of thing has passed ham radio by. It has been a long time since ham radio was a source of innovation. When did it exist, and when did it end? I blame the Morse cultists who hijacked amateur radio for use as their personal playground. When and how did that happen, exactly? I see a lot of claims but no specifics or history. �The infrastructure that is being wasted on Morse includes band segments that have, until recently, been reserved for its exclusive use. What band segments are those, specifically? In the USA, there have been no Morse-code-exclusive-use band segments (except on 6 and 2 meters) for many years. My 1962 ARRL License Manual has the FCC rules for the Amateur Radio Service, and at that time - 46 years ago - there were no Morse-code-exclusive-use band segments on the HF bands, or any VHF/UHF band above 2 meters. And the rules weren't new then. OTOH, even today, data modes are prohibited from using the voice subbands in the USA. Do you consider a rules change that happened more than 46 years ago to be "recently"? 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). "Now" includes at least the past 46 years. There is also the inclusion of keyer provisions in HF radios. Which costs practically nothing. It will be interesting to see what the marketplace does to code tapes and code keys. There are more keys on the market now than when I became a ham 40 years ago. I don't think they will last long. I think they will. 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. Yes - because of the slowness of the FCC to change Part 97 after the treaty changed in 2003. Other countries began dropping that requirement many years earlier, while still claiming to be in compliance with their treaty obligations. Which countries? Please be specific. How do you explain that? I only know for certain of one country that had a no-code-test HF amateur radio license before 2003. There may be others, but not many. Japan has long had a nocodetest HF amateur license called the 4th class. But that license was and is limited to low power levels (10 watts) and to parts of the amateur bands which are worldwide exclusively allocated to amateurs. Japan's claim was that the treaty exists to prevent interference between users of different radio services and between users o the same radio service in different countries. By limiting 4th class JA hams to only worldwide amateurs-only bands, interference to other services was prevented. By limiting 4th class amateurs to very low power, and since Japan is an island nation, interference to amateurs of other countries was prevented. Nobody challenged Japan on it, either. But Japan still requires a Morse Code test for at least some of its higher-class amateur licenses. The USA does not. 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. But why? In 1990, FCC created medical waivers for the 13 and 20 wpm Morse Code tests, but not 5 wpm. FCC said they would have waivered all the tests except for the treaty. Same for the reduction of all license classes to 5 wpm in 2000. Opposition to these changes did not stop FCC. Would you have preferred that FCC violate the treaty? Or create a license class similar to Japan's 4th class? 73 de Jim, N2EY |
#26
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Some additional info about US subbands-by-mode, in reply to Klystron's
mention of exclusive Morse-code-only band segments. In the following discussion, "modes" means "modes authorized for use by amateurs on the specific amateur bands in question". The current US regulation of the HF amateur bands permits Morse Code everywhere, voice and image modes on specific subbands, and data modes wherever voice is not permitted. Morse Code has no exclusive subbands at all, and is rarely used in the 'phone subbands. (I've been an active ham 40+ years and never used Morse Code in an HF voice subband). These regulations are descendants of those going back many decades, to times when amateur operation on HF consisted of Morse Code, voice and nothing else. (For example, HF RTTY operation by US hams was first authorized in the late 1940s, but only 45.45 baud 5 level Baudot code was allowed.) A few years ago, ARRL proposed "Regulation By Bandwidth", which would have separated the various modes by the bandwidth of the signal rather than whether it was voice, data, image, etc. For example, under the proposal, any mode less than 500 Hz wide would be allowed in the 500 Hz and wider subbands, regardless of whether it carried voice, data, image, Morse Code or other information. There were also proposed changes to where automatic and semi-automatic data-mode stations could operate. The proposal got an RM number and a comment period. The comments from those interested were overwhelmingly against the proposal. It was revised but to no avail; ARRL finally withdrew the proposal. IMHO, the most common reasons for opposition that I saw reading the comments were these (in no particular order): 1) 'Phone operators did not want any data modes in the 'phone subbands. 2) "Robot" (unattended) digital stations should be confined to small subbands. 3) Concern that amateurs would have to be able to measure the actual occupied bandwidth of their transmitted signals or be subject to violation notices and complaints. Older equipment and hams who could not afford spectrum analyzers would be forced off the air seemed to be a common fear. 4) AM voice would be limited to 9 kHz bandwidth and was essentially "grandfathered", but other modes could not exceed 3.5 kHz on most bands 5) The existing rules did not need changing. The FCC did act on an earlier "refarming" proposal by ARRL, and widened the 'phone/image subbands on some of the HF bands at the end of 2006. However, FCC went far beyond the ARRL recommendations in the amount of change. This effectively reduced the spectrum space available for data modes on those bands, since they could not be used where 'phone is allowed. The most radical change was on the 80/75 meter bands. About the same time as the "Regulation by Bandwidth" proposal, a group of less than a dozen amateurs calling itself the "Communications Think Tank" (CTT) proposed the even more radical change of eliminating subbands-by-mode completely, and simply specifying a maximum signal bandwidth for each band. This proposal also got an RM number and a comment period, but the comments were even more solidly against it than against "Regulation by Bandwidth". The opposition was so overwhelming that CTT also withdrew its proposal. The point of all this is that ARRL and others have made proposals to fundamentally change Part 97 in ways that would favor the use of data modes, and the US amateur community has repeatedly and strongly opposed those proposals. 73 de Jim, N2EY |
#27
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#28
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On Mar 24, 1:41 pm, Cecil Moore wrote:
wrote: The current US regulation of the HF amateur bands permits Morse Code everywhere, ... My ARRL Band chart says "USB phone only" for 60m. Hello Cecil! You are correct, sir! Thanks! While it could be argued that the five channels known as "60 meters" are not be an "HF amateur band" in the sense that, say, 20 meters is, they are HF and only upper-sideband voice is permitted to US amateurs there. So amend the above to read: "The current US regulation of the HF/MF amateur bands permits Morse Code on all frequencies except the five USB-voice-only channels known as '60 meters', ..." 73 es TNX de Jim, N2EY |
#29
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Phil Kane wrote:
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. My understanding is that ntpd can handle that problem quite well. An OPTIMAL setup would involve 1 computer per radio, each acting as a radio controller (also called a strata 0 server). You could have a radio for WWVB or WWVH, a second radio that is set to scan the WWV frequencies and a third "radio" for GPS. Those 3 computers would connect to a fourth computer that would act as a strata 1 server. The result would be a time server that is as accurate as if it were connected to other ntp servers via the Internet. Such an arrangement is sometimes used by firms that need metrology-grade time service on a secured, internal LAN. By the way, do not be put off by the expense of the four (or more) computers described above. According the ntp documentation that I have read, they need to have at least 100 MHz processor speeds for optimum accuracy, but there is no benefit in going much above 100 MHz. Thus, a pile of old, junkyard computers will do the job quite well and at an aggregate cost of $20 to $100 in total. -- Klystron |
#30
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