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#1
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Dee:
This "show me", "show me" you are repeating causes a complete confusion on my part. Will you agree that a 56K phone modem, does indeed, transmit this data rate with an audio bandwidth of ~300Hz to ~5000K, and if you do so agree, how can you argue this cannot fit in a HF AM RF signal which only goes 2.5K each side of center frequency?????????? Are you NOT imposing an audio frequency of AT LEAST a 5K bandwidth on the rf carrier with normal speech? (actually, most quality transceivers have a wider audio bandwidth than this which can be set +/-) and if you agree you are indeed, how can you argue that 5K bandwidth can carry a 56K data rate over a phone line--and NOT a hf rf signal???? That looks insane to me? The modem is NOT using the whole 5K bandwidth--necessarily, there is compression into a narrower bandwidth which can and is generally software controlled--if necessary (the modems software is a LOT smarter than most give it credit for, especially in the case of the old "onboard processor" and "hardware logic" USRobotics external modems. You need to explain to me why it even begins to look difficult to you for me to be able to understand what you are asking? As, I have to be missing something here... You do realize that a picture good enough to run a "webcam" on the amateur HF bands and get an acceptable image from can be done in 28K (or less depending on the fps), and 36K is really fine at 5 fps and good at 10 fps--you will be able to see the wart on the guys nose you are video conferencing with at 36K!!! You know, I have not even looked to see on the web, but aren't tons of people doing this right now as we newsgroup? I suppose you could actually use the rf signal as data carrier itself and modulate it directly through on/off switching, as opposed to modulating the rf carrier with the audio data carrier... but that would take some heavy duty equip mods/revamps, if it didn't wipe out the neighbors cable tv! grin Think about this: at 100 mhz if you can precisely control the EXACT amplitude of each and every cycle of rf out the back end of the xmitter, you have a virtual 100mbs data carrier... most are working here... 450 MHz? 1Ghz? 12Ghz? .... and of course, the receiver has to be able to decipher the amplitudes of each cycle back to a data stream for the video card... .... this is the land where dreamers are... John "Dee Flint" wrote in message ... "John Smith" wrote in message ... Mike: 300 baud is ridiculous, in Dee's first post mentioning 300 baud I tossed it out the window--that was fine up to about 1985, then only the mentally challenged continued to run 300 baud modems! Please show me and everyone else how we can run more than 300 baud on HF without exceeding reasonable band widths. There are a whole lot of things, not just video, that would be nice to do. How can we do it? Bandwidth is directly related to baud rate. Dee D. Flint, N8UZE |
#2
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![]() John Smith wrote: Dee: Will you agree that a 56K phone modem, does indeed, transmit this data rate with an audio bandwidth of ~300Hz to ~5000K, and if you do so agree, how can you argue this cannot fit in a HF AM RF signal which only goes 2.5K each side of center frequency?????????? Of course it can. The question is whether the RF path will have characteristics comparable to those of the telephone line. Are you NOT imposing an audio frequency of AT LEAST a 5K bandwidth on the rf carrier with normal speech? No. Typical ham transceivers only need about 2.5 kHz of audio bandwidth. (actually, most quality transceivers have a wider audio bandwidth than this which can be set +/-) and if you agree you are indeed, how can you argue that 5K bandwidth can carry a 56K data rate over a phone line--and NOT a hf rf signal???? That looks insane to me? It's a question of the characteristics of the RF path. Certainly there are some paths that will support the amplitude- and phase- stable requirements of the 56K modem - and some paths that won't. On top of that is the fact that most RF paths aren't full duplex. How fast is the 56K modem in half-duplex with transmit-receive switching? The modem is NOT using the whole 5K bandwidth--necessarily, there is compression into a narrower bandwidth which can and is generally software controlled--if necessary (the modems software is a LOT smarter than most give it credit for, especially in the case of the old "onboard processor" and "hardware logic" USRobotics external modems. You need to explain to me why it even begins to look difficult to you for me to be able to understand what you are asking? As, I have to be missing something here... You are. Do you think HF offers the same transmission characteristics as a telephone line? You know, I have not even looked to see on the web, but aren't tons of people doing this right now as we newsgroup? On telephone wires or HF radio? I suppose you could actually use the rf signal as data carrier itself and modulate it directly through on/off switching, as opposed to modulating the rf carrier with the audio data carrier... but that would take some heavy duty equip mods/revamps, if it didn't wipe out the neighbors cable tv! grin Think about this: at 100 mhz if you can precisely control the EXACT amplitude of each and every cycle of rf out the back end of the xmitter, you have a virtual 100mbs data carrier... most are working here... 450 MHz? 1Ghz? 12Ghz? Think about the stability of the RF path at HF. ... and of course, the receiver has to be able to decipher the amplitudes of each cycle back to a data stream for the video card... ... this is the land where dreamers are... John "Dee Flint" wrote in message ... "John Smith" wrote in message ... Mike: 300 baud is ridiculous, in Dee's first post mentioning 300 baud I tossed it out the window--that was fine up to about 1985, then only the mentally challenged continued to run 300 baud modems! Please show me and everyone else how we can run more than 300 baud on HF without exceeding reasonable band widths. There are a whole lot of things, not just video, that would be nice to do. How can we do it? Bandwidth is directly related to baud rate. Dee D. Flint, N8UZE |
#3
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N2EY:
First, you can run duplex, simply use two modems and a separate transmitter and receiver. The second modem can be a USR internal if you don't have two serial ports for externals. To run duplex with one modem, there is some kind of patch device they used to keep the receiver output from getting on the mic input of the transmitter (but the modem had simultaneous access to both)--and for the life of me, I can't remember what it was called, first time I had ever seen one. When I get a chance, I will ask about it. You might know what it is/was? Second, it works, build one--or--draw it on paper and decide it does not work. I am on to other things, I got tired of webcams years ago. Don't even video chat on irc, MSN Messenger, ICQ messenger or yahoo messenger much anymore. And that is much easier than "Mac Amateur IM." I can tell, this argument will shortly switch to rules and regulations, it always does, and I have no interest in having such recited to me. Expect only my bad nature in return. I didn't do the hardware or even know the "true nature" of the signal which comes out of that modem and hits the phone line or a mike in. I just toyed with the software and watched it work--it "lived" in my garage for a year or so. I am into my "universal translator" these days and trying to set up to chat fluently with the russians... I think the russian girls are kind of cute... grin John wrote in message oups.com... John Smith wrote: Dee: Will you agree that a 56K phone modem, does indeed, transmit this data rate with an audio bandwidth of ~300Hz to ~5000K, and if you do so agree, how can you argue this cannot fit in a HF AM RF signal which only goes 2.5K each side of center frequency?????????? Of course it can. The question is whether the RF path will have characteristics comparable to those of the telephone line. Are you NOT imposing an audio frequency of AT LEAST a 5K bandwidth on the rf carrier with normal speech? No. Typical ham transceivers only need about 2.5 kHz of audio bandwidth. (actually, most quality transceivers have a wider audio bandwidth than this which can be set +/-) and if you agree you are indeed, how can you argue that 5K bandwidth can carry a 56K data rate over a phone line--and NOT a hf rf signal???? That looks insane to me? It's a question of the characteristics of the RF path. Certainly there are some paths that will support the amplitude- and phase- stable requirements of the 56K modem - and some paths that won't. On top of that is the fact that most RF paths aren't full duplex. How fast is the 56K modem in half-duplex with transmit-receive switching? The modem is NOT using the whole 5K bandwidth--necessarily, there is compression into a narrower bandwidth which can and is generally software controlled--if necessary (the modems software is a LOT smarter than most give it credit for, especially in the case of the old "onboard processor" and "hardware logic" USRobotics external modems. You need to explain to me why it even begins to look difficult to you for me to be able to understand what you are asking? As, I have to be missing something here... You are. Do you think HF offers the same transmission characteristics as a telephone line? You know, I have not even looked to see on the web, but aren't tons of people doing this right now as we newsgroup? On telephone wires or HF radio? I suppose you could actually use the rf signal as data carrier itself and modulate it directly through on/off switching, as opposed to modulating the rf carrier with the audio data carrier... but that would take some heavy duty equip mods/revamps, if it didn't wipe out the neighbors cable tv! grin Think about this: at 100 mhz if you can precisely control the EXACT amplitude of each and every cycle of rf out the back end of the xmitter, you have a virtual 100mbs data carrier... most are working here... 450 MHz? 1Ghz? 12Ghz? Think about the stability of the RF path at HF. ... and of course, the receiver has to be able to decipher the amplitudes of each cycle back to a data stream for the video card... ... this is the land where dreamers are... John "Dee Flint" wrote in message ... "John Smith" wrote in message ... Mike: 300 baud is ridiculous, in Dee's first post mentioning 300 baud I tossed it out the window--that was fine up to about 1985, then only the mentally challenged continued to run 300 baud modems! Please show me and everyone else how we can run more than 300 baud on HF without exceeding reasonable band widths. There are a whole lot of things, not just video, that would be nice to do. How can we do it? Bandwidth is directly related to baud rate. Dee D. Flint, N8UZE |
#4
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![]() John Smith wrote: N2EY: First, you can run duplex, simply use two modems and a separate transmitter and receiver. Uh-huh. Got it. The reciever listens while the transmitter transmits. On the same frequency. 'Way to go "John", slap a patent on it! Bwwwahaha! |
#7
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wrote:
wrote: John Smith wrote: N2EY: First, you can run duplex, simply use two modems and a separate transmitter and receiver. "John" just convinced me that he knows very little about radio - HF amateur radio in particular. Took long enough, Jim! ;^) Uh-huh. Got it. The reciever listens while the transmitter transmits. On the same frequency. 'Way to go "John", slap a patent on it! Bwwwahaha! Did you notice there was no mention of antennas? Isotrons. It would at least look kinda kewl. 8^) Poor soul prolly doesn't know what "QSK" means, either. Does it matter?....... - Mike KB3EIA - |
#8
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From: on Tues 5 Jul 2005 16:41
John Smith wrote: N2EY: First, you can run duplex, simply use two modems and a separate transmitter and receiver. Uh-huh. Got it. The reciever listens while the transmitter transmits. On the same frequency. 'Way to go "John", slap a patent on it! Did John say "on the same frequency?" I don't think so. FULL duplex IS possible using SEPARATE frequencies for transmit and receive. [note spelling of "receive"] Did that over 50 years ago on 9 terminals at 1.8 GHz. Full duplex. Twenty-four voice channels each terminal. No problem. Bwwwahaha! Tsk. Started "happy hour" early, did you? :-) bit bit |
#9
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![]() wrote: From: on Tues 5 Jul 2005 16:41 John Smith wrote: N2EY: First, you can run duplex, simply use two modems and a separate transmitter and receiver. Uh-huh. Got it. The reciever listens while the transmitter transmits. On the same frequency. 'Way to go "John", slap a patent on it! Did John say "on the same frequency?" I don't think so. He didn't say *not* on the same frequency either Sweetums. Now what? FULL duplex IS possible using SEPARATE frequencies for transmit and receive. No kidding Sweetums I've done it several times myself. With my own equipment operated under my own operators and station license. But in your case of course . . sigh |
#10
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From: on Wed 6 Jul 2005 15:54
wrote: From: on Tues 5 Jul 2005 16:41 John Smith wrote: N2EY: First, you can run duplex, simply use two modems and a separate transmitter and receiver. Uh-huh. Got it. The reciever listens while the transmitter transmits. On the same frequency. 'Way to go "John", slap a patent on it! Did John say "on the same frequency?" I don't think so. He didn't say *not* on the same frequency either Sweetums. Now what? Two questions: 1. What ELSE did John "*not* say?" 2. What are you going to say he "really said?" :-) This is all very clever of you, but it really boils down to YOU saying a lot of snit (that another didn't say) and then trying to tap-dance around admitting you fudged things up. Next time just accept being caught and hang up. Do NOT try to MAKE UP STORIES to try and snow-job everybody. It doesn't work and it annoys the other pigs. FULL duplex IS possible using SEPARATE frequencies for transmit and receive. No kidding Sweetums I've done it several times myself. With my own equipment operated under my own operators and station license. Mostly I think you "did it" with only your own computer and more literary license than you ever earned. :-) But, that's just my opinion...and with some considerable thinking about HF operations that hardly EVER go FULL duplex, senior. For one thing, the rather large near field at HF wavelengths mean you NEED considerable separation of antennas or the most bodaciously-many-section-dual-filter to keep the unwanted frequencies (transmitter leaking into receiver) OUT. That attenuation has to be VERY large in order to keep the receiver input from overloading. Now, WHY would you want to go FULL duplex "operating under any license?" for personal use? You would need someone at the other end of the circuit doing the same thing...and that is an almost- extreme rarity. Telephone Cell sites operate 24/7 at FULL duplex. They HAVE to and the equipment is designed to do that...such as separate transmitting and receiving bands with plenty of diplexing filter connecting the transmitter(s) and receiver(s). The General Electric microwave terminals I've described used a (approximately) 5-foot long dual waveguide bandpass filter to keep separate transmit and receive frequencies from interfering with one another. The pulse-position-modulation pulse trains were not synchronous with one another, thus aiding in isolation. The peak power output of the transmitter was only 12 Watts (at base of antenna tower) yet the receiver was about as sensitive as one could get (using radar receiver techniques) of the 1950s. If you are going to mumble about "your own moonbounce" (what is mistakenly called "EME" by hams), then you need not worry about mutual interference. A return signal won't return from the moon for about 2.5 seconds, long enough for you to manually swtich coax or waveguide between transmit and receive (as one of the early ham moonbouncers did and pictured in CQ long ago). Or, you could go into broadband BS about using morse and auto- switchover Tx/Rx by fancy diode T/R switching...so much so that you could "read the other station between dots and dashes" like your buddie Jimmie once said in here. :-) But in your case of course . . sigh In "my case" you are resentful/insulted/irritated because another had LONG AGO experience in something YOU DID NOT. shrug I've come to expect that in here from the self-propelled wunderkinder of the PCTA extra crowd. It's practically a given. :-) |
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