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WPM to BPS calculation
Phil Kane wrote:
Klystron wrote: Thus, a pile of old, junkyard computers will do the job quite well and at an aggregate cost of $20 to $100 in total. Four such computers in a single box would be ideal for the way I run my ham data-modes (packet/PACTOR/APRS/BPSK31 setup - 24/7 each). Too bad we can't get that in a box the size of a toaster at a price that is less than $100. The 'box the size of a toaster' part is out, but could you settle for 4 old blade servers, 1U size each, in a rack mount? If so, find a surplus property auction in your area (large state university, government agency, etc.) and you will probably be able to pick up something along those lines. -- Klystron |
WPM to BPS calculation
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WPM to BPS calculation
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. |
WPM to BPS calculation
Phil Kane wrote:
On Mon, 24 Mar 2008 00:10:13 EDT, wrote: 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. 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. -- The only thing that has changed since the first sattelite launched is that the accuracy degrading dither for civilian use was removed about 7 years ago. With the dither the time accuracy was in the range of tens of microseconds. Whereever you were getting your six seconds of error from, it wasn't from the GPS system. -- Jim Pennino Remove .spam.sux to reply. |
WPM to BPS calculation
Phil Kane wrote:
On Mon, 24 Mar 2008 18:13:01 EDT, AF6AY wrote: The only problem there is that it ALSO is a 'set-up' kind of 'test' (any touch-typist on a TTY would 'win') and has very little entertainment value. My secretary at March AFB (early 1960s) could and did type faster than the Model 28 could cut tape. It frustrated her no end. My cohort at the old U.S. Embassy in Guinea-Bissau and I could jam one up as well. Nothing like poking tape on numerous multi-page outgoing cables five or six days per week to build typing speed and technique. The 28's were set up so that we never saw what we typed appear on paper. If you really wanted to check your work, you'd have to gather up the perf tape and look at it. Those machines were replaced just after I left Bissau in late 1987. I took the very last State Department 28 in Africa out of service in Sierra Leone in 1990. We had to destroy the innards, but a colleague wanted the cabinet. He re-worked the thing and turned it into a bar in his living room. His wife arrived at post a couple of months later and the new bar was quickly relegated to the fellow's ham shack. During my early time at State, most places were using Teletype Model 40 equipment with the three 8" disk drives and the fastest, most rugged impact printer I'd ever seen. That stuff was gradually replaced by computer equipment in the 1987 to 1992 time frame. I ran a Model 15 in Cincy and also had a Model 33 for a while. I wanted a 28 with the 3-speed gear shift badly. W8JIN offered me one long after I'd begun using a Commodore C-64. I gave it about thirty seconds thought before rejecting it as too big and heavy. Len's point about touch typists winning a speed contest with Morse ops would depend entirely upon how fast the typist was. The second junior op I had in Bissau would have been lucky to do 30 wpm on a keyboard. With the teletype model 40 stuff, there was not any typing of cables at all. Secretaries typed the cable and they were fed into an OCR. The operator might have to correct a formatting error or the occasional misread character. With the advent of the classified LAN's and the computerized equipment, drafters would electronically release cable text and addressees to the communications center and the ops would send the messages. Incoming traffic was routed in the same way, mostly automatically. Anything not understood by the computer would route to a 'spill que' to be manually assigned action and info offices. Occasionally the Deputy Chief of Mission would telephone or e-mail a request that the action office for a given cable be changed. By then, part of our work involved keeping message router databases (the military addressees--especially Navy--could change frequently) up to date. The computerization was supposed to result in the paperless office. It didn't. The stuff was just printed somewhere other than in the comm center. Dave K8MN |
WPM to BPS calculation
On Mar 24, 5:10�pm, Klystron wrote:
wrote: Klystron wrote: Are you familiar with the Internet-based ntp system? Such a system requires connectivity to the internet. WWVB does not; just requires a receiver. A computer running ntpd can get metrology-grade time service from radio signals. ntpd can use radio only, Internet only or both. That is more complex and costly than a $50 wris****ch or wall clock, however. And it takes a lot more attention than simply keeping batteries in it. 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. I take it that you don't know what "machine language" is. Actually, I do. Humans are not supposed to be involved. Why not? If they are, it's not machine to machine communications. Why does it matter? Morse Code can be machine-to-machine, machine-to-human, human-to-machine, or human-to-human. That's a big plus. 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. � �Utter hogwash. It wasn't developed from ARPANET? It started out as a network of Universities and a few defense contractors' laboratories. DoD funded, then. Maybe not directly, but still DoD funded. It wasn't a bunch of self-funded basement experimenters. Much of the funding came from the individual Universities. The contribution of the government (via the defense contractors) was not absolutely necessary. But it was there. Besides, after the Tappan worm incident, the networks were split into ARPAnet and DARPAnet (with a "D," as in defense). The public Internet is descended from the s mall slice of that pie. How does that make what I wrote "utter hogwash" in any way? 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. � �Again, that is preposterous nonsense. Why? Was there no legislation needed to make the internet as we know it possible? Was there no one working to make it easier to use? 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. � �The Internet opened to the general public in 1993 and 1 994. 14-15 years ago. So I got online 3 to 4 years after the beginning. At that time, there were essentially no courses at accredited Universities that covered UNIX, TCP/IP, the Internet or related topics. No courses in UNIX at all? You had to learn it on your own. The Universities mainly taught MVS and 360/370 architecture. 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. The Internet was not commercial in origin. When I first gained access, I had to sign an agreement not to use it for commercial purposes. Sending out for pizza via e-mail would have been a violation and would have resulted in account cancellation. But than, that was long ago. Spam hadn't been invented yet. And how long did that no-commercial-use restriction last? It was long gone in 1997. 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. � �The CW bands were those band segments that excluded voi ce. But they have included data modes like RTTY for more than 46 years. Every Hz of them. You claimed: "infrastructure that is being wasted on Morse includes" band segments that have, until recently, been reserved for its exclusive use." Note the terms "is being wasted" and "until recently". But no such band segments (except 2.5% of 6 and 2 meters) have existed for at least 46 years. Not only that, but modes besides FSK RTTY have been common on the HF amateur bands since at least the early 1980s. Until fairly recently, there was no such thing as "data." Please define "fairly recently". 10 years? 20 years? 46 years? All of the non-voice parts of the bands have been open to data modes for decades. That hams didn't use them much 30-40 years ago wasn't because of Morse Code. There was some RTTY, but it was never a major issue. When? For many decades, the traffic in the HF ham bands was SSB voice or CW. Hams began using SSB voice in the early 1930s. It became more popular in the late 1940s and really took off in the late 1950s-early 1960s. But there was also AM voice, narrowband FM voice, RTTY, SSTV, and even some FAX. A pie chart would show a very small slice labeled "other." Perhaps, 30-40 years ago. Think about why that was. It wasn't because of Morse Code. 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. What about code tapes? How much longer will they last? They've been largely replaced by Morse Code training software, like G4FON's. No need to buy tapes anymore, just download some free software and make your own. Or download files to your MP3 player or iPod. My guess is that those keys are sold only to replace other keys. My observation is that a considerable number are sold to new hams who want to *use* Morse Code on the air. Is that wrong? Should hams not learn, use or promote Morse Code anymore? I doubt that there are very many first time key buyers today. I know a couple. And since the usable life of a key is measured in decades, the need for replacements is pretty limited. And consider this: There are a considerable number of companies making CW-only or CW-centric low-power HF amateur transceivers. They are being sold in the tens of thousands. For example, a new company called Elecraft appeared in 1999 selling a CW-only QRP HF transceiver *kit* for a bit under $600. To date, more then 6000 have been sold, with minimal advertising. The company later produced other CW-only transceiver kits, and they have sold well with minimal advertising. 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 of the same radio service in different countries. � �So you admit that different countries interpreted their treaty obligations in different ways? I know that Japan used that logic to get around the ITU-R treaty requirement. Do you know of *any* other country (besides Japan) that had a nocodetest amateur radio license with HF privileges before 2003? Would you have preferred that FCC violate the treaty? Or create a license class similar to Japan's 4th class? �I'm not going to spend a lot of time doing your research for you, but there was more then one treaty and those treaties expired or were modified over a period of years. I have researched the subject. The treaty in question is the ITU-R treaty, to which the USA is a signatory. That's not just my opinion; it's what the FCC has repeatedly written in its Report and Orders. Before July 2003, in part S25.5, the ITU-R treaty required that all amateur licenses which grant privileges below 30 MHz had to have Morse Code tests. That requirement was made optional at WRC 2003. Signatory countries could retain Morse Code testing or eliminate it, as they chose. Some have chosen to reduce or eliminate it. Others have not. No-code HF licenses came about over time in a number of countries. How many countries besides Japan had them before July 2003? How many have them now? The US was either one of the last to drop code or was dead last to do so. Japan still requires Morse Code for First Class licenses. Canadians have the option of passing a Morse Code test or getting a higher score on the written exam. Most of the countries in the former Soviet Union still require Morse Code testing. In any event, here in the USA: - there has been a nocodetest amateur radio license for more than 17 years - all classes of amateur license have been available for just a 5 wpm test for 18 years with medical waiver, and for almost 8 years without such a waiver. - Morse Code testing has been completely gone for more than a year. Yet US amateurs continue to use the mode extensively. Some use it exclusively. 73 de Jim, N2EY |
WPM to BPS calculation
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. |
WPM to BPS calculation
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. |
WPM to BPS calculation
On Mon, 24 Mar 2008 18:10:15 EDT, Klystron wrote:
GPS can only be used where the satellites can be "seen" by the receiver. In or near the continental US, that is not an issue. It is a big issue in my comm room which is partially underground with concrete walls (what they call a "daylight basement" here) where neither WWVB nor GPS signals penetrate. I have not yet found an "atomic clock" (either digital or analog) that has an external antenna collection - they may exist but not at the consumer level. The consumer-grade clocks that I have sync well on the "upper" story but do not hold their accuracy for long. And to add insult to injury, the analog wall clock that I use by intent has a face with the marine "silent period" and "auto alarm" markings, a configuration well known to shipboard radio operators. For a $20 quartz clock it keeps time remarkably well, considering that I have to manually adjust it at "DST" time changes anyhow. -- 73 de K2ASP - Phil Kane From a Clearing in the Silicon Forest Beaverton (Washington County) Oregon e-mail: k2asp [at] arrl [dot] net |
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