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From: Mike Coslo on Aug 7, 9:24 am
an old friend wrote: Dave Heil wrote: Mike Coslo wrote: BTW, CQ has an article on HF digital transmission. Seems that they have got it all wrong too. They have a method that works, but it is pretty slow for images (or files) of any appreciable size. HF will never be the place for high speed digital transmission. There is too much noise and signals are subject to the vagaries of wave propagation phenomena. Why do you keep beating this Dead Horse on "rapid transmission of high speed digital transmission?" Shannon's Law is absolute, proven by experiment, embraced by all the OTHER radio services. Shannon's Law is 58 years old and mature, both de facto and de jure. "Vagaries of wave propagation phenomena" [at HF due to ionospheric changes] has been well-known to academia, the commercial and government users of HF since the 1930s. The most well-known (to non-amateur communications on HF) is "selective fading," a relatively short-duration change of BOTH amplitude and phase over a relatively narrow band-span. In commercial SSB (using 12 KHz bandwidth format of four 3 KHz separate voice-grade circuits) this was much reduced in its effect by simply sending TWO tone-pair sets for each AFSK TTY circuit, the pair separated by about 1 to 2 KHz; voting circuitry at the receive end picked out the "best" received signal. That reduced at least 95 percent of the error effects of selective fading. The "charge" that high-speed data transmission is "impossible" due to some (unquantified) "phase changes" has been thrashed and discarded by at least two HF digital voice transmission methods, one of which (DRM or Digital Radio Mondial) has been in test for five years and is now heard over two dozen HF broadcasts. DRM can carry binaural ("stereo") audio. The bandwidth occupancy is NO GREATER than a conventional monoaural AM transmission. The key to such untilization of a relatively narrow bandwidth for higher throughput lies in examination of the environment and using coding theory to fit that environment. Will it send "high-quality" digital pictures in data mode? YES, but at relatively slow transmission rates depending on the bandwidth used/allowed/allocated. Shannon's Law is irrefutable. It will NOT carry "live, feature-length motion pictures." [that seems to be your goal but that goal is not possible to attain] It can send high-density image data without problem, with a minimum of error, but a cost of waiting a relatively long time for each image. There are OTHER forms of on-the-fly determination of "the vagaries of propagation" [on HF]. The U.S. government has been using a standardized method for about five years now called Automatic Link Establishment or ALE. While perhaps not adapatable to amateur radio HF applications, it is a system for continuously monitoring signal quality, a scan of other predetermined frequencies to check their quality, and automatic changeover to whichever predetermined frequency signal quality is best. ALE on HF has been devised and tested expressly for HF beginning about two decades ago. Both of the above mainly-HF systems have been little publicized in the amateur radio press. That is a fault of the amateur radio publishers, not the system. It is NOT the simplistic basic-level radio theory (and coding theory) which can be easily digested in a single reading sit-down. They require THINKING, "non-traditional" thinking away from what had been theory of a half century ago and propagated as "state-of-the-art" long after its first appearance. On pushing throughput to much greater rates in relatively narrow bandwidths, consider the advances in amateur radio HF techniques over the last half century. In the 1950s the "standard" RTTY frequency-shift was 850 Hz for 60 WPM TTY 5-level coding. Today it is 170 Hz for 100 WPM 8-level TTY coding. AM voice used to take at least 6 KHz bandwidth but single-channel suppressed-carrier sideband cut that in half plus reducing the old AM heterodynes from CW carriers. PKS31 innovated and devised in the UK, tested in Europe, was a 30 WPM RTTY system using a bandwidth no larger than a conventional on-off keyed "CW" (morse code) signal. Those are now "accepted" methods because the amateur radio press has publicized it. However, in OTHER areas, look at the common, ordinary PC modem operating with Plain Old Telephone System (POTS) lines of 3 KHz bandwidth. The data rate over the "56K" modem is about NINETEEN TIMES FASTER than "straight" analog AM. MILLIONS are used each day in the USA alone. You don't look into the WHY of such a large increase in throughput and I don't understand why you don't. The answer lies in combinatorial modulation PLUS some rather simple coding theory to increase the data bit rate to a top of 56 THOUSAND bits per second. The modulation of the modem's audio tone carrier is a combination of AM and PM. It does NOT violate Shannon's Law. Such an EQUIVALENT system could be applied to HF (it is in the TORs or Teletype Over Radio outboard boxes) but that can be incorporated into an HF transceiver as an integral part. All of the radio amateurs, duly licensed as part of the "nation's service" and complete with federally- authorized call signs, seem to be satisfied with the LAZY way out...let someone else do the innovation and design. They won't "accept" it until the product ad appears in QST ready for shipment, has reviews from the "ARRL Lab" and all can argue over the ad specifications. Packaged innovation ready to go. Done by OTHERS. Everything for "the bands" (meaning only HF). "Standardized." :-( I've brought up "scaling" of data rates before but that seems to be a non-understanding topic. It isn't in a convenient QST or CQ or QEX article so it isn't "accepted." Yet SCALING is done (has been for decades) in antenna testing as well as data rate. Look at high-definition television broadcasting that is now phasing in to consumers. The image throughput is more than doubled PLUS extra data is sent for quadraphonic sound (not just "stereo") and closed-captioning in a channel space NO LARGER than (in the USA) 6 MHz. It's a three times REDUCTION in bandwidth...PLUS more than double the amount of video data. The secret is in the MPEG (Motion Picture Experts Group) digitized video data coding and compression. Not only that, the image/sound quality is very nearly FREE of all the "propagation vagaries" due to phase and analog changes from moving reflections, greater immunity to random noise (such as from tools or appliances). SOMETHING EQUIVALENT might be done for audio on HF...perhaps scaling down the present-day SSB bandwidth of about 2.1 KHz to just 700 Hz or maybe 1 KHz...more than double the band occupancy for voice signals and with much greater immunity to "flutter" and selective fading effects. Look at the WLANs (Wireless Local Area Networks) now in use by the hundreds of thousands daily, perhaps a dozen or more in the local vicinity of other WLANs...AND in the same band as cordless telephones (dozens more) and high- data-rate systems such as CCTV monitors or music distribution (dozens more). Each is NOT INTERFERED WITH by all the other local systems, all can operate as if the others did not exist. The secret to their success is Distributed Spread Spectrum techniques plus coding theory. Every system EXISTS in the same bandwidth yet each is separate and undisturbed by others. No "heterodynes," no need for fancy, expensive filters-in-the-IF, or ultimate refinements of decades-old conventional techniques. But, you don't seem to care about such possibilities or even getting a hint of what might be possible. You, like way too many others will only "accept" something if someone else has worked it out and it is a PRODUCT on the market. Then you can sit around and natter about the advertising phrases and argue someone's "lab reviews" and sound like "expert radiomen" of "extra" class when you don't know dink about its insides. Intellectual SLOTH. LAZINESS. All you wanna do is play wid yer raddios and pretend to radio greatness. shrug dit bit |
an_old_friend wrote:
Mike Coslo wrote: There are some pretty darn good reasons why high-speed digital HF won't work well. And they aren't related to early "knowledge" that caused hams to be relegated to those higher frequencies at the time. agreed there are reasons of course as there were then but it is folks like you with "it can not be Done.. therefore it should not be disused etc. that insure it can't be done I choose to look at a thorny problem and try to see if I can make lemonaide, maybe brew those throns in a decent cup of Tea Radio is a fairly mature field, and digital is getting there. Many people have a pretty good idea what will likely work, based on education and experience. And HF is an unruly beast, given to noisy and incredibly variable conditions. We don't have to be rocket scientists to gain that knowledge. Just as an exercise, how much information can be carried by a 1.8 MHz signal? How much error correction will be needed during the summer, and how much during the winter? Why is there a difference? Why would a wireless digital transmission system use UHF and above for data transmission? in sprict order asking I don't know, don't know, difering weather conidctions, and becuase comercail needs relaiblity where we hams are free to spend on trying stuff Yep, that is what I figured. - Mike KB3EIA - - |
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Of course, but Communism is done, right??? hi hi.
Russia has NOT dropped Morse. Nor has most of the ex Eastern Block countries. Years ago when I was in Germany in the US Army it was decided to fire back up on CW training. The reason was because the Ruskies were having a field day trashing our HF nets. We were on AM/SSB/RATT (RTTY), and they would get close, or right on top of them on CW. It was a total flop because hardly anyone in the US Military new Morse well enough to copy it. Point is this. The Russians and their close neighbors are smart enough to realize Morse is a worth while mode and will continue its use. Dan/W4NTI "John Smith" wrote in message ... Dan: What communist counties do is almost always in the interest of the shadow gov't really running the country. That is supposed to be surprising? John On Sat, 06 Aug 2005 00:06:36 +0000, Dan/W4NTI wrote: Minor correction "John Smith". If the USA decided not to drop CW, it would NOT be alone in world. Russia and her ex Soviet Block nations have all decided to keep CW. Dan/W4NTI "John Smith" wrote in message ... Dave: Well, there is debate and argument for good and reason, and then there is not... Then there is religious devotion to a test which serves only a select few... It would be interesting if the powers that be were to decide in keeping CW--and then explain why they alone in the world community made that decision, frankly, I would be happy not to have that task... There are plentiful examples of insanity in this world... that old book which bears the title something like "The Emperor Wore No Clothes" is as meaningful today as the day it was written... John "Dave Heil" wrote in message nk.net... John Smith wrote: N2EY: Nice attempt at "spin doctoring" for the weak minded... It is like fishing, you bait your hook, toss it in the water and see what bites... John At least that's how you do it, "John". Dave K8MN On Fri, 05 Aug 2005 09:36:54 -0700, N2EY wrote: John Smith wrote: Here the NCI offers proof and spells it out, just in case these old key tappers are in danger of pulling some wool over your eyes... http://www.nocode.org/articles/filter.html As some have noted in the past, "There are liars, and there are DAMN LIARS!" Omission of relevant facts can be a form of lying. Here's the whole story: I read that bit of W5YI propaganda, and also the original articles in "200 Meters And Down" and the QSTs of the time. (have you done so?) The referenced article does not give all the relevant facts. For one thing, the article claims that "higher speed" code testing has been used to "limit the number of hams since the very beginning of ham licensing". The fact is that all US hams were licensed in the US by 1912, 24 years before the 1936 happenings cited. The code test speed after 1919 was 10 wpm, and the 1936 increase to 13 wpm - hardly a quantum leap. To get a clear picture of what was actually happening, it is important to understand what ham radio was like back in those days. After WW1, ham radio almost ceased to exist. It was brought back to life by the dedicated efforts of a few enthusiasts. Amateur radio was not even recognized by international treaty until 1927. The 1927 treaty resulted in stricter new rules and much-narrowed bands. By 1929 there were about 16,000 hams in the US. Almost all of them were on the 160, 80, 40, and 20 meter bands. A typical ham transmitter was a self-controlled power oscillator, and a typical ham receiver was a three tube regenerative. Sure, more advanced techniques existed, but few hams could afford them in thos Great Depression years. Code skill was important in almost all radio services. 10 wpm was not considered as anything like professional level - 25 or 30 wpm was more like it. (This was with semiautomatic keys for sending and manual typewriters for highspeed copy). 1929 saw two big changes to ham radio. The treaties signed in 1927 came into effect, which cut deeply into the 40 and 20 meter hambands (70% of 40 was lost, and 80% of 20). The treaties also required much cleaner signals from ham rigs. The Great Depression followed soon afterwards. But the Depression and the new regs had a surprising effect on ham radio. The number of hams took a sharp upturn in the early thirties. By 1935 there were over 46,000 hams - almost TRIPLING the number of just five years earlier! But the turnover in amateur radio was approaching 40% per year. This meant that most hams were raw newcomers, with relatively little technical knowledge or operating skills. A ham with 5 years on the air was a veteran, one with 10 years was a grizzled old timer. Problems of interference and crowding abounded. Complaints from other services threatened the existence of ham radio. The problem was that thousands of newcomers were learning just enough to pass the tests, assembling simple stations with little understanding of proper design, adjustment, or operation, and putting them on the air. Many of these newcomers lost interest quickly, particularly when the limitations of their knowledge and skills became apparent. The newly formed FCC was concerned, as was the ARRL. The action proposed by the ARRL to the FCC was in two parts: Raise the code speed SLIGHTLY, (10 to 12-1/2 wpm) and make the written test more comprehensive. The changes to the written tests are all but ignored by the NCI article. The goal was NOT to limit the total number of hams, nor to hinder or deter anyone from getting a license, but to control the flood of newcomers, and make sure that the new folks had the necessary skills and knowledge. Look at the complete picture, and the action of the FCC in 1936 makes sense. 73 de Jim, N2EY |
"an old friend" wrote in message oups.com... Dan/W4NTI wrote: Minor correction "John Smith". If the USA decided not to drop CW, it would NOT be alone in world. Russia and her ex Soviet Block nations have all decided to keep CW. and you WANT the US to keep such company Absolutely I want us to keep such company. Hows the old saying go? Keep your enemies close and your friends closer. Dan/W4NTI |
Dan:
Too bad the americans had not developed HS Digital Checksum Error Corrected Voice Transmission Packet methods over spread spectrum... could have filtered the CW audio and went right on, would have pi$$ed 'em off in style! Oh well, too late for back then, but today we can! John On Sun, 07 Aug 2005 22:27:35 +0000, Dan/W4NTI wrote: Of course, but Communism is done, right??? hi hi. Russia has NOT dropped Morse. Nor has most of the ex Eastern Block countries. Years ago when I was in Germany in the US Army it was decided to fire back up on CW training. The reason was because the Ruskies were having a field day trashing our HF nets. We were on AM/SSB/RATT (RTTY), and they would get close, or right on top of them on CW. It was a total flop because hardly anyone in the US Military new Morse well enough to copy it. Point is this. The Russians and their close neighbors are smart enough to realize Morse is a worth while mode and will continue its use. Dan/W4NTI "John Smith" wrote in message ... Dan: What communist counties do is almost always in the interest of the shadow gov't really running the country. That is supposed to be surprising? John On Sat, 06 Aug 2005 00:06:36 +0000, Dan/W4NTI wrote: Minor correction "John Smith". If the USA decided not to drop CW, it would NOT be alone in world. Russia and her ex Soviet Block nations have all decided to keep CW. Dan/W4NTI "John Smith" wrote in message ... Dave: Well, there is debate and argument for good and reason, and then there is not... Then there is religious devotion to a test which serves only a select few... It would be interesting if the powers that be were to decide in keeping CW--and then explain why they alone in the world community made that decision, frankly, I would be happy not to have that task... There are plentiful examples of insanity in this world... that old book which bears the title something like "The Emperor Wore No Clothes" is as meaningful today as the day it was written... John "Dave Heil" wrote in message nk.net... John Smith wrote: N2EY: Nice attempt at "spin doctoring" for the weak minded... It is like fishing, you bait your hook, toss it in the water and see what bites... John At least that's how you do it, "John". Dave K8MN On Fri, 05 Aug 2005 09:36:54 -0700, N2EY wrote: John Smith wrote: Here the NCI offers proof and spells it out, just in case these old key tappers are in danger of pulling some wool over your eyes... http://www.nocode.org/articles/filter.html As some have noted in the past, "There are liars, and there are DAMN LIARS!" Omission of relevant facts can be a form of lying. Here's the whole story: I read that bit of W5YI propaganda, and also the original articles in "200 Meters And Down" and the QSTs of the time. (have you done so?) The referenced article does not give all the relevant facts. For one thing, the article claims that "higher speed" code testing has been used to "limit the number of hams since the very beginning of ham licensing". The fact is that all US hams were licensed in the US by 1912, 24 years before the 1936 happenings cited. The code test speed after 1919 was 10 wpm, and the 1936 increase to 13 wpm - hardly a quantum leap. To get a clear picture of what was actually happening, it is important to understand what ham radio was like back in those days. After WW1, ham radio almost ceased to exist. It was brought back to life by the dedicated efforts of a few enthusiasts. Amateur radio was not even recognized by international treaty until 1927. The 1927 treaty resulted in stricter new rules and much-narrowed bands. By 1929 there were about 16,000 hams in the US. Almost all of them were on the 160, 80, 40, and 20 meter bands. A typical ham transmitter was a self-controlled power oscillator, and a typical ham receiver was a three tube regenerative. Sure, more advanced techniques existed, but few hams could afford them in thos Great Depression years. Code skill was important in almost all radio services. 10 wpm was not considered as anything like professional level - 25 or 30 wpm was more like it. (This was with semiautomatic keys for sending and manual typewriters for highspeed copy). 1929 saw two big changes to ham radio. The treaties signed in 1927 came into effect, which cut deeply into the 40 and 20 meter hambands (70% of 40 was lost, and 80% of 20). The treaties also required much cleaner signals from ham rigs. The Great Depression followed soon afterwards. But the Depression and the new regs had a surprising effect on ham radio. The number of hams took a sharp upturn in the early thirties. By 1935 there were over 46,000 hams - almost TRIPLING the number of just five years earlier! But the turnover in amateur radio was approaching 40% per year. This meant that most hams were raw newcomers, with relatively little technical knowledge or operating skills. A ham with 5 years on the air was a veteran, one with 10 years was a grizzled old timer. Problems of interference and crowding abounded. Complaints from other services threatened the existence of ham radio. The problem was that thousands of newcomers were learning just enough to pass the tests, assembling simple stations with little understanding of proper design, adjustment, or operation, and putting them on the air. Many of these newcomers lost interest quickly, particularly when the limitations of their knowledge and skills became apparent. The newly formed FCC was concerned, as was the ARRL. The action proposed by the ARRL to the FCC was in two parts: Raise the code speed SLIGHTLY, (10 to 12-1/2 wpm) and make the written test more comprehensive. The changes to the written tests are all but ignored by the NCI article. The goal was NOT to limit the total number of hams, nor to hinder or deter anyone from getting a license, but to control the flood of newcomers, and make sure that the new folks had the necessary skills and knowledge. Look at the complete picture, and the action of the FCC in 1936 makes sense. 73 de Jim, N2EY |
From: John Smith on Sun 7 Aug 2005 10:31
Len: With each passing year mother nature war on the ancient brass pounders continues. This story has been told in many different countries in many different forms, here we are probably most familiar with "The Rabbit and the Hare." Slow and steady stay the course, in the end progress and determination succeed... Thanks for a mediocre Obi Wan Kenobi imitation. sigh Problem is, I ain't Luke Skywalker...but all the pro-coders think they are Dearth Voder. Tsk. I was giving you only a little insight how things were IN HERE about 6 to 7 years ago. Was no "John Smith" in here then. obi wan |
Dan/W4NTI wrote: "an old friend" wrote in message oups.com... Dan/W4NTI wrote: Minor correction "John Smith". If the USA decided not to drop CW, it would NOT be alone in world. Russia and her ex Soviet Block nations have all decided to keep CW. and you WANT the US to keep such company Absolutely I want us to keep such company. Hows the old saying go? Keep your enemies close and your friends closer. Nice comeback I honestly didn't think you had it in you, well done Dan/W4NTI |
From: John Smith on Aug 7, 3:38 pm
Dan: Too bad the americans had not developed HS Digital Checksum Error Corrected Voice Transmission Packet methods over spread spectrum... could have filtered the CW audio and went right on, would have pi$$ed 'em off in style! Oh well, too late for back then, but today we can! The only thing WRONG with this back-and-forth is Dan's claim of Disability from Vietnam. The Vietnam War ended in 1975, THIRTY YEARS AGO. Had he been in communications with the military in Yurp "after" that, he wouldn't have any "disability" since he would be on active duty. If Dan Jeswald got out of the military DUE to warfare in Vietnam, then his personal experience from Yurp military exercises is THIRTY YEARS OLD. Present-day, and back in the FIRST Gulf War times, U.S. land forces most definitely have COMSEC (COMmunications SECurity) which pretty well defeats old-style jammers. The first instance of that was the AN/PRC-119 family, "SINCGARS," which is a selectable digital-voice/data, single frequency or frequency hopper on 30 to 88 MHz. It became operational in the U.S. Army in 1989, first sets to Army in Korea. At frequency hops of 10 per second, it is virtually immune to standard (old-style) jamming and very resistant to "noise jamming." [it's damn hard to detect, let alone jam] Later ("SIP") versions available by the SECOND Gulf War ("Revenge of the Shrub") had fully built-in COMSEC (voice scrambler no longer an external box) and half the size of the original manpack. A QUARTER MILLION R/T sets (manpack, vehicular, airborne) have been produced to the end of 2004 and all fielded. The land forces use a variety of radios and pieces of the EM spectrum, NOT so totally dependent on HF as Dan would have you believe. For MOST of the message transmissions, those go through VHF, UHF, troposcatter, and microwave radio systems with microwave dominating the major relays through military comm sats...one reason why CENCOM could command the 2nd Gulf War from Florida. As to HF radios in the military land forces, the AN/PRC-104 family (20 W manpack through 400 W PEP vehicular) is a synth frequency control unit for a full 3 to 30 MHz span and with automatic antenna tuner (even in the manpack!) and direct connections to COMSEC boxes. Designed and built by Hughes Aircraft Ground Division, it became operational first in 1986. It will be replaced by the AN/PRC-150 family designed by Harris, called by them "Falcon II." The "150" is more resistant to jamming and has built-in COMSEC. What these very amateur "military analysts" don't understand is that the RUSSIAN comm equipment "sold" to Iraq in the 1st Gulf War ALSO HAD SS-LIKE RF SCRAMBLING. That was back in 1990, 15 years ago. [they also had very Russian armor in which they carried those NON-morse-code radios] As to the alleged "CW intel from behind the lines" BS spouted by a few in here back some 6 to 7 years, the U.S. Army had the (now obsolete and replaced with newer) UHF portables with built-in data, "chiclet" keyboards, LCD mini-screens and with three different portable antennas to shoot to the comm sats or to orbiting comm relay aircraft. None of this nonsense of easy-to-DF HF slow-speed "CW" where the RF was spraying in all directions from omnidirectional antennas. Data rate then was 1200 BPS and the antennas directional. Whatever the Russians do in amateur regulations is a FAR cry from what they field in their army...as modern as any even if they have meager maintenance and not as much of the good stuff as the US military has. "WE" know HOW to jam them, or at least most of what they have for radios...the reverse has NOT been true for at least 15 years. You can take my word of it or not. I didn't "stop" working in communications for any part of DoD after my Honorable Discharge in 1960. I've played with SINCGARS and entered enough hopsets through its touch-screen front panel. I would have personally liked to work on the PRC-104, at least in operational testing, but other contract work called. What I've remarked on in public here is FROM public information that anyone can get, on paper or electronically. Instead, we have all these other "military analysts" claiming ten kinds of "knowledge" (some allegedly personal) which, in all likelyhood, comes from Popular Mechanics or old TV shows. Even the "FAS" (Foundation of American Scientists) is behind the times with old data from the 1980s. Better than nothing, I suppose. One thing for sure, the Russian amateur radio regs are NOT formulated to "build up a pool of trained morsemen" to serve in their military for their national whatevers. Geez, if all these renowned AMATEUR military radio experts were telling like it is, the USAF recruiting posters would feature "Air Crews For B-17s and B-24s" and the USA would still have sojer pictures with pre-1940 'dish' helmets and lace-up leggings a la 1940. :-) Unless something new has come up, WT Docket 05-235 is NOT concerned whether or not the Russkies still test for morse code. The FCC doesn't regulate in Russia...any more than Stebie Wundermurine "regulates" Somalian radio. Whatever Russia cares to do after WRC-03 is THEIR concern, not ours. We and the Brits have to help them raise their mini-subs or record their interceptor comms as they shoot down Korean civil airliners (played back in front of the UN some time ago). On the other hand, a regular columnist at ANTENNEX website is Russian and they are NOT sticking with 1950s technology these days. But, there's some ruff-and-tuff commie sympathizers talking at ya, John, and don't nobody step in THEIR way! :-) Dosvedanya droog Ivan day off |
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