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#1
July 4th 05, 04:55 PM
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Mike Coslo wrote:
Dave Heil wrote: wrote: How we be gonna scale those pictures and live video to fit into 2.5 KHz? Two steps: 1) Convert the pictures and video into highly-compressed digital formats for transmission. 2) Use different modes/modulations/protocols Shannon's Theorem tells us that we can get very high data rates through very narrow bandwidths *if* we have adequate signal-to-noise ratio. Note that "noise" takes many forms, not just the thermal noise we're used to. For example, PSK has an advantage over OOK when dealing with thermal noise. But when dealing with other types of noise, OOK can have an advantage. It all depends on the transmission medium. What works on a telephone line may not work on an HF path of the same apparent bandwidth. I thought that we were going to be able to send live video and digital images on HF? You can do that now - just need enough S/N. Simply by hooking our computers to our rigs via the proper interfaces. And software. Now it seems that the *idea* is that we are going to use DRM, and we're going to need to get more spectrum in which to use. There are all sorts of solutions. But there's a world of difference between people talking theory and actual application. Most of all, some folks confuse the journey and the destination. Does complex and newer equal better? Sometimes. Not always. Is analog simpler than digital? Sometimes! Does having a computer that attaches to the Internet make a person a digital expert? Some folks think so! I don't. And besides - "digital expert" doesn't mean someone knows much about radio. I ask for enlightenment, I get invective. Are you surprised? Appears to be what there is to offer. Now consider how effective such a person would be trying to sell amateur radio - with or without a code test. 73 de Jim, N2EY |
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#2
July 4th 05, 06:04 PM
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N2EY:
Most of that is incorrect. First you use "on the fly" encryption/decryption/"data compaction" and have it occurring in "real time." This has the effect of being "transparent" and the user is not even aware that it is going on. Next, forget the sn/noise ratio other than it has to acceptable for transmission of understandable communication (however, this is required no matter what the form of data--i.e., voice, ssb, cw, etc) Next, listen to digital signal occupying audio bandwidth (it is audio bandwidth that is of concern here, NOT rf bandwidth, except with the possibility of fm and how you implement the data compression and transmission, i.e., just make it fit the existing rf bandwidth and NO changes are needed--however, larger rf bandwidth will ALWAYS result in a drastic increase in transmission speed and wideband fm can easily offer itself to 1MBS and faster) a digital signal can be treated just like a analog signal if desired, the use of CRC checksums and error checking of the data is just more intense under these circumstances and there is NO standard established for this--so you MUST be able to make and use your own custom hardware and software. To avoid this, just grab off the shelf digital hardware/software. Next, for every patented form of audio video protocols there are FREE forms, usually the free ones are more acceptable, efficient and suitable to ones needs, an example: Use ogg vobis compression of audio as opposed to mp3 --in video-- Use xvid as opposed to divx 4-5 However, any of this requires a sound and current education and knowledge of the state of technology--and something which is obviously lacking here. John wrote in message oups.com... Mike Coslo wrote: Dave Heil wrote: wrote: How we be gonna scale those pictures and live video to fit into 2.5 KHz? Two steps: 1) Convert the pictures and video into highly-compressed digital formats for transmission. 2) Use different modes/modulations/protocols Shannon's Theorem tells us that we can get very high data rates through very narrow bandwidths *if* we have adequate signal-to-noise ratio. Note that "noise" takes many forms, not just the thermal noise we're used to. For example, PSK has an advantage over OOK when dealing with thermal noise. But when dealing with other types of noise, OOK can have an advantage. It all depends on the transmission medium. What works on a telephone line may not work on an HF path of the same apparent bandwidth. I thought that we were going to be able to send live video and digital images on HF? You can do that now - just need enough S/N. Simply by hooking our computers to our rigs via the proper interfaces. And software. Now it seems that the *idea* is that we are going to use DRM, and we're going to need to get more spectrum in which to use. There are all sorts of solutions. But there's a world of difference between people talking theory and actual application. Most of all, some folks confuse the journey and the destination. Does complex and newer equal better? Sometimes. Not always. Is analog simpler than digital? Sometimes! Does having a computer that attaches to the Internet make a person a digital expert? Some folks think so! I don't. And besides - "digital expert" doesn't mean someone knows much about radio. I ask for enlightenment, I get invective. Are you surprised? Appears to be what there is to offer. Now consider how effective such a person would be trying to sell amateur radio - with or without a code test. 73 de Jim, N2EY |
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#3
July 4th 05, 07:31 PM
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John Smith wrote:
N2EY: Most of that is incorrect. Most of what? First you use "on the fly" encryption/decryption/"data compaction" and have it occurring in "real time." This has the effect of being "transparent" and the user is not even aware that it is going on. That's what "Convert the pictures and video into highly-compressed digital formats for transmission." means, John. Whether it's done in "real time" is just a detail. Next, forget the sn/noise ratio other than it has to acceptable for transmission of understandable communication (however, this is required no matter what the form of data--i.e., voice, ssb, cw, etc) Signal-to-noise is an integral part of Shannon's thereom. It cannot simply be "forgotten". Next, listen to digital signal occupying audio bandwidth (it is audio bandwidth that is of concern here, NOT rf bandwidth, No, that's not correct. The discussion is about transmitting pictures and video on the amateur HF/MF bands. RF bandwidth is a very important thing there. except with the possibility of fm and how you implement the data compression and transmission, i.e., just make it fit the existing rf bandwidth and NO changes are needed--however, larger rf bandwidth will ALWAYS result in a drastic increase in transmission speed and wideband fm can easily offer itself to 1MBS and faster) a digital signal can be treated just like a analog signal if desired, the use of CRC checksums and error checking of the data is just more intense under these circumstances and there is NO standard established for this--so you MUST be able to make and use your own custom hardware and software. To avoid this, just grab off the shelf digital hardware/software. And the simplest way for hams to do that at HF/MF is to use an SSB transceiver and a computer with a sound card. But that's not the only issue. Next, for every patented form of audio video protocols there are FREE forms, usually the free ones are more acceptable, efficient and suitable to ones needs, an example: Use ogg vobis compression of audio as opposed to mp3 --in video-- Use xvid as opposed to divx 4-5 And make sure the folks at the other end are similarly equipped. However, any of this requires a sound and current education and knowledge of the state of technology--and something which is obviously lacking here. Yes, John, your lack of a sound and current education about amateur HF/MF communications is quite evident. Good to see you admitting it. There's also the issue of FCC regulations. Of course those regulations can be changed, and there are several proposals in development or before the FCC to change them. But until they are changed, amateurs will be constrained by the current rules, such as the 300 baud limitation on HF. The vast majority of hams are not going to break those rules, regardless of the available technology or their education. The question raised by KB3EIA and N8UZE remains: How can video be sent in a 2.5 kHz RF bandwidth on the amateur HF bands? I've answered that question in a theoretical way. I don't think you even understand the question and all its implications, John. wrote in message oups.com... Mike Coslo wrote: Dave Heil wrote: wrote: How we be gonna scale those pictures and live video to fit into 2.5 KHz? Two steps: 1) Convert the pictures and video into highly-compressed digital formats for transmission. 2) Use different modes/modulations/protocols Shannon's Theorem tells us that we can get very high data rates through very narrow bandwidths *if* we have adequate signal-to-noise ratio. Note that "noise" takes many forms, not just the thermal noise we're used to. For example, PSK has an advantage over OOK when dealing with thermal noise. But when dealing with other types of noise, OOK can have an advantage. It all depends on the transmission medium. What works on a telephone line may not work on an HF path of the same apparent bandwidth. I thought that we were going to be able to send live video and digital images on HF? You can do that now - just need enough S/N. Simply by hooking our computers to our rigs via the proper interfaces. And software. Now it seems that the *idea* is that we are going to use DRM, and we're going to need to get more spectrum in which to use. There are all sorts of solutions. But there's a world of difference between people talking theory and actual application. Most of all, some folks confuse the journey and the destination. Does complex and newer equal better? Sometimes. Not always. Is analog simpler than digital? Sometimes! Does having a computer that attaches to the Internet make a person a digital expert? Some folks think so! I don't. And besides - "digital expert" doesn't mean someone knows much about radio. I ask for enlightenment, I get invective. Are you surprised? Appears to be what there is to offer. Now consider how effective such a person would be trying to sell amateur radio - with or without a code test. 73 de Jim, N2EY |
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#4
July 4th 05, 08:03 PM
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N2EY:
that is all wet. Although an increase in bandwidth can be used to transmit more data, what we are discussing is the protocol of binary transmission in the form of video data and in an agreed upon structure over a roughly ~5K audio bandwidth--or--simply put, data throughput measured in bits (or bytes, or words (16 bits), or double-words (32), etc, per second. This all can be done with existing, common equipment modified to do so, and easily at rates of 56K, over the audio bandwidth of most transceivers (or with minor modifications of the transceivers audio circuits), with most remain ignorant to the fact it is being done at all! If some hams want to jack around all the standards and methods which are already in place--screw with current terminology and "encode" all this to "ham words/terminology/technology" with the hope of obfuscating the facts and making it appear that the hams have invented the internet, have at it! I am sure the digital youngsters will find this a strong draw to amateur radio. The technology has been out there for over a decade, in everyday use for 5 years or better, and now is used widely in industry for security monitoring, etc. You can buy it off the shelf... The real experimenters have now moved on and use nothing less than 100MBS+ nic cards and wireless wans interfaced to transceivers through computers over spread spectrum... which some one will point out is a violation of FCC regs for amateur radio bands. It will probably be another 10 years before hams "invent" this new gig. Possibly longer if they sit around and argue whether it can be done or not... ROFLOL John wrote in message oups.com... John Smith wrote: N2EY: Most of that is incorrect. Most of what? First you use "on the fly" encryption/decryption/"data compaction" and have it occurring in "real time." This has the effect of being "transparent" and the user is not even aware that it is going on. That's what "Convert the pictures and video into highly-compressed digital formats for transmission." means, John. Whether it's done in "real time" is just a detail. Next, forget the sn/noise ratio other than it has to acceptable for transmission of understandable communication (however, this is required no matter what the form of data--i.e., voice, ssb, cw, etc) Signal-to-noise is an integral part of Shannon's thereom. It cannot simply be "forgotten". Next, listen to digital signal occupying audio bandwidth (it is audio bandwidth that is of concern here, NOT rf bandwidth, No, that's not correct. The discussion is about transmitting pictures and video on the amateur HF/MF bands. RF bandwidth is a very important thing there. except with the possibility of fm and how you implement the data compression and transmission, i.e., just make it fit the existing rf bandwidth and NO changes are needed--however, larger rf bandwidth will ALWAYS result in a drastic increase in transmission speed and wideband fm can easily offer itself to 1MBS and faster) a digital signal can be treated just like a analog signal if desired, the use of CRC checksums and error checking of the data is just more intense under these circumstances and there is NO standard established for this--so you MUST be able to make and use your own custom hardware and software. To avoid this, just grab off the shelf digital hardware/software. And the simplest way for hams to do that at HF/MF is to use an SSB transceiver and a computer with a sound card. But that's not the only issue. Next, for every patented form of audio video protocols there are FREE forms, usually the free ones are more acceptable, efficient and suitable to ones needs, an example: Use ogg vobis compression of audio as opposed to mp3 --in video-- Use xvid as opposed to divx 4-5 And make sure the folks at the other end are similarly equipped. However, any of this requires a sound and current education and knowledge of the state of technology--and something which is obviously lacking here. Yes, John, your lack of a sound and current education about amateur HF/MF communications is quite evident. Good to see you admitting it. There's also the issue of FCC regulations. Of course those regulations can be changed, and there are several proposals in development or before the FCC to change them. But until they are changed, amateurs will be constrained by the current rules, such as the 300 baud limitation on HF. The vast majority of hams are not going to break those rules, regardless of the available technology or their education. The question raised by KB3EIA and N8UZE remains: How can video be sent in a 2.5 kHz RF bandwidth on the amateur HF bands? I've answered that question in a theoretical way. I don't think you even understand the question and all its implications, John. wrote in message oups.com... Mike Coslo wrote: Dave Heil wrote: wrote: How we be gonna scale those pictures and live video to fit into 2.5 KHz? Two steps: 1) Convert the pictures and video into highly-compressed digital formats for transmission. 2) Use different modes/modulations/protocols Shannon's Theorem tells us that we can get very high data rates through very narrow bandwidths *if* we have adequate signal-to-noise ratio. Note that "noise" takes many forms, not just the thermal noise we're used to. For example, PSK has an advantage over OOK when dealing with thermal noise. But when dealing with other types of noise, OOK can have an advantage. It all depends on the transmission medium. What works on a telephone line may not work on an HF path of the same apparent bandwidth. I thought that we were going to be able to send live video and digital images on HF? You can do that now - just need enough S/N. Simply by hooking our computers to our rigs via the proper interfaces. And software. Now it seems that the *idea* is that we are going to use DRM, and we're going to need to get more spectrum in which to use. There are all sorts of solutions. But there's a world of difference between people talking theory and actual application. Most of all, some folks confuse the journey and the destination. Does complex and newer equal better? Sometimes. Not always. Is analog simpler than digital? Sometimes! Does having a computer that attaches to the Internet make a person a digital expert? Some folks think so! I don't. And besides - "digital expert" doesn't mean someone knows much about radio. I ask for enlightenment, I get invective. Are you surprised? Appears to be what there is to offer. Now consider how effective such a person would be trying to sell amateur radio - with or without a code test. 73 de Jim, N2EY |
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#6
July 5th 05, 12:32 AM
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"Mike Coslo" wrote So here we are. Yup, and no one has persuaded me it can't be done. I've only been persuaded that we haven't figured out how yet. (Sorta reminds you, doesn't it, of how those old-tymey hams must have felt when they were told to take their party to "200 meters and below".) You, Jim, and Dee bemoaning how hard it will be, and John raising the tantalizing notion that we may only be a few "eureka!!!"s away from something workable. Outside my area of competence, but I'll watch the dialog with interest. 73, de Hans, K0HB |
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#7
July 5th 05, 01:59 AM
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"KØHB" wrote in message ink.net... "Mike Coslo" wrote So here we are. Yup, and no one has persuaded me it can't be done. I've only been persuaded that we haven't figured out how yet. (Sorta reminds you, doesn't it, of how those old-tymey hams must have felt when they were told to take their party to "200 meters and below".) You, Jim, and Dee bemoaning how hard it will be, and John raising the tantalizing notion that we may only be a few "eureka!!!"s away from something workable. Outside my area of competence, but I'll watch the dialog with interest. 73, de Hans, K0HB From my understanding of John's comments, he is saying it can be done now with current technology. He does not however tell us how. He just chatters on about "compressing it enough" without stating the degree of compression, etc. Hey I'm all for the "eureka" when it happens but the problem is that it is unpredictable. Not only is it unpredictable in time but in the nature of the breakthrough. Dee D. Flint, N8UZE |
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#8
July 5th 05, 02:13 AM
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"Dee Flint" wrote Hey I'm all for the "eureka" when it happens but the problem is that it is unpredictable. Not only is it unpredictable in time but in the nature of the breakthrough. That's what makes ham radio some damn much fun! In my profession role I can send a team of engineers off with some marketeers scribbling and know that within 12-18 months I'll be shipping product. Bnt ham radio is not so predicable --- we get these delightful surprises from unexpected places. Some like APRS and PSK-xx gain traction and thrive in a niche, others like AX.25 packet radio and 2-meter autopatches which blossom like an Independence Day firework, then fizzle to a few sparks on the ground after a short period of glory. Then there are a few genuine "revolutions" which fundamentally change the nature of amateur radio. We're about due for one of those. 73, de Hans, K0HB |
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#9
July 5th 05, 02:59 AM
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Dee:
You don't understand binary compression techniques, ok... .... it all has to do with binary trees (well, mostly, kind of), in software, of the data stream, multiple bytes are converted into "data streams", i.e., a pixel "byte" at this level is NOT necessarily 8 bits long in a stream, and sometimes can be represented by a single bit (automatic compression to 1/8 size just because it is stored in a binary tree! (or, data stream) multiple occurring bytes can be sent in the form of (five of these) or ((67 - number of bytes) of (00100100 - binary data byte to create 67 of)), in other words you tell it how many of ONE type of data to create on the other end to fill in the "video hole" on the screen, I would think you can visualize how small a simple BW image can be transmitted--it grows bigger with grayscale data, and much bigger with color data (in quality pictures an extra few bits have to be sent just to describe the color/brightness of the pixel being sent...) .... there is also "variable bit rate compression" which I don't even want to begin to try to give a simplified explanation of here... I am sorry, my ability to describe these complex methods at work here is lacking, and I realize this... don't trust me on it, the web is loaded with papers on every aspect of it... The size of compressed data? That depends on the data types compressed, BW video can be 90%+ compressed (resulting in data 1/10 to 1/20 the size, or MORE, it all just depends on the complexity of the image.) For example, a completely white frame would be (for example) 1,024,000 bytes of color 00000000--this whole screen could be transmitted in TWO BYTES! and the same for an all black screen, at EXTREME RESOLUTION in this simplified case. Further "compression" can be had down at the hardware level where the transmission software can "scan" data and "table-ize" streams of duplicate bytes, or very similar bytes which can all be represented by a common value with little or no detectable loss in "realized visual quality." (can you really tell almost-almost black from "real" black? Or, almost-almost-blue from "real" blue?) In a very efficient compression scheme, it can be "mentally modeled" as a onion, where many "layers" of compression are occurring in a tight sequential loop creating very tightly compressed data packets, with crc sums to ensure no data corruption and packets sequentially numbered to provide a "sane" display stream (this can frequently be rather lax with low quality audio (speech) and less than absolute perfect video.) Digital cell phones use very similar techniques on audio. Some of the "trade secrets" there are closely protected... It is really beyond the resources we have here to go into a deep explanation on data compression techniques, and cheap tricks and short cuts--a good book on the subject should bring one up to speed quickly--perhaps amazon.com for those with a desire for a in-depth understanding... Now some "cheap tricks" examples: you can actually throw away every other pixel (immediately cut the size of a video frame in half!) by using a "normalized" colored pixel in those "dropped" pixels place (and normalizing this "fill in pixel color" as needed to fit the "general background" of the rest of the picture--with NOT as great a loss of video quality as you would expect (or a smaller percentage of "normalized" pixels if greater quality is really needed) and, a smaller than screen sized "picture" can be broadcast and "expanded" by "image size extrapolation" (computer makes a lot of guesses on how to represent it as a larger picture and "fill the screen"--and attempts to have those "guesses" maintain a reasonable quality of picture. and, I could go on and on, however, this is quickly becoming WAY beyond the scope of the arena we need to hold this "argument/discussion" within... and there are papers and books which can do a much finer job than I... I must say, Len was quite correct in the appraisal of your mental aptitude, I would venture to say this with confidence, as damn few women would have hung with this technical discussion as you have... .... are you single, just how old are you? leering-smile .... just kidding, well, mostly--I AM single yanno! grin Warmest regards, John "Dee Flint" wrote in message ... "KXHB" wrote in message ink.net... "Mike Coslo" wrote So here we are. Yup, and no one has persuaded me it can't be done. I've only been persuaded that we haven't figured out how yet. (Sorta reminds you, doesn't it, of how those old-tymey hams must have felt when they were told to take their party to "200 meters and below".) You, Jim, and Dee bemoaning how hard it will be, and John raising the tantalizing notion that we may only be a few "eureka!!!"s away from something workable. Outside my area of competence, but I'll watch the dialog with interest. 73, de Hans, K0HB From my understanding of John's comments, he is saying it can be done now with current technology. He does not however tell us how. He just chatters on about "compressing it enough" without stating the degree of compression, etc. Hey I'm all for the "eureka" when it happens but the problem is that it is unpredictable. Not only is it unpredictable in time but in the nature of the breakthrough. Dee D. Flint, N8UZE |
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#10
July 5th 05, 04:03 AM
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KØHB wrote:
"Mike Coslo" wrote So here we are. Yup, and no one has persuaded me it can't be done. I've only been persuaded that we haven't figured out how yet. (Sorta reminds you, doesn't it, of how those old-tymey hams must have felt when they were told to take their party to "200 meters and below".) You, Jim, and Dee bemoaning how hard it will be, and John raising the tantalizing notion that we may only be a few "eureka!!!"s away from something workable. He also give a lot of solid technical ways in which this can be done, eh? Outside my area of competence, but I'll watch the dialog with interest. Hey, Hans, ignorance is not a crime! Note that Jim brought up an *actual* method of trying to do a lot of BW using 256 or more phase angles that are decoded by the receiving station. That is not likely to work at HF, but a simplified version of this is used for some satellite comms. they (see my link in my post to Jim) note that QPSK is more reliable - or at least suffers less from link degradation - same thing, than 8PSK. But there is some theory there that can be discussed. And as for "bemoaning", I have been asking for something based in solid theory since early in this thread. Most of what I have gotten in return is that I am an olde tyme ham (untrue) stuck on CW with my Bug (paraphrased, but laughably untrue), and topic shifted to DRM voice (technically working, but beside the point). That ain't substance. |
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