duntemann.wbst@sri-unix (11/23/82)
Flames indeed! I could smell this all coming. First the techies admit timidly that they never did like code and think it might not be necessary to require all hams to learn it. Then the "spark forever" chaps dive in and claim that CW is absolutely essential, that it is the most efficient use of our band space, that it is the necessary "barrier" to keep out throngs of CBers who would ruin hamming for everybody. And, yes, a final rejoinder that CW is fun and should not be done away with altogether. What was that again? Do away with it altogethner? Who said anything about that? We were talking about making CW an oPTIOnAL part of ham radio...like, maybe giving people a choice? What a peculiar notion...kind of like giving people a choice as to whether or not they have to join a union to keep their jobs. Unions virtually froth at the mouth when such a thing is suggested, usually claiming that making unions optional is a plot to "do away with unions altogether." Funny how making something optional is a plot to do away with it altogether. Maybe such an assertion is just an aggressive way of admitting that very few people really WANT CW or labor unions, and that if optional, they would be pitched over the rail in short order. Think about it. Other issues: CW is the most efficient use of our bandwidth. Nonsense. CW buys narrowness of bandwidth at the cost of throughput. The real measure of band usage efficiency is the quantity of information passed per second per unit of bandwidth. Measuring this accurately is NOT trivial. I'm not sure it's ever been tried. I was a novice, and I worked CW as long as I had to. I dropped it because it was painfully, agonizingly slow. I pondered that speeding it up to the throughput of a phone signal would probably make it just as wide as a phone signal. Bandwidth increases as information density increases. Sorry about that. The only way to increase band-usage efficiency is to be real tricky-- to pack information into the dead spots, to stop going "um,ahhhh" and dah didididah, dah didididah, etc. In short, to use packet techniques, and all the other neat stuff Bob Van Valzah might teach us if we'd just let him in. Now let's talk about Barriers. We need barriers to test the mettle of prospective hams so that we don't allow the Tennesee Toilet Flusher to Git Awn the Channul and take over. Agreed. But why CW as a barrier? What does it buy us other than a brick wall? It buys us dedicated hams who can pound brass. Does it buy us hams who know how to design advanced digital filters? No. Does it buy us hams who can define and implement really and truly efficient modes of information transfer? No. It gives us dedicated brass pounders. It gives us nothing to advance the art past where we're already at. If we're to have a barrier, give us a barrier that improves the art. I think an EE/digital barrier would be much more appropriate. I probably couldn't pass it right now. But I would durn well crack a book and study it until I could, figuring that in the process I was learning something that would be of genuine use, not something that had gotten the last ounce of efficiency squeezed out of it thirty years ago. More could be said, but I've said enough. A proposal, then: Make the CW test 5WPM for all license classes to satisfy the treaties, leave the CW bands as they are, and let N2XS and the novices do their thing. Make the tests much tougher to keep the yahoos out. Give hams a choice. All in favor say aye. All opposed, click your keys. Somebody else tally it up. I gotta go back to work. 73, Jeff Duntemann KB2JN (Packets forever!)
Denber.WBST@sri-unix (11/23/82)
"if optional, they would be pitched over the rail in short order" Right - but why stop there? Let's get rid of speed limit laws, and license plates for cars - who needs them either? How about income taxes - if anything ought to be optional, that's it. Seriously, if you want to join the club, pay the admission fee. For a mere 5 wpm. you can can your very own Tech. Come on guys, do you know how *s l o w* that is? You can pass that just by memorizing A through Z and doing table lookup in your mind for each letter (although that's certainly no way to really learn the code). Sure, there's arguments on both sides, but in the time it takes you to grump about how unfair life is, you could have learned the code. "Oh the farmer and the cowboy should be friends, Oh the farmer and the cowboy should be friends. One man likes to pound a key, The other uses SSB, But that's no reason why they can't be friends." - Michel KB2BQ
haney.EOS@sri-unix (11/23/82)
AMEN, TERRY WA6OAD
KOHNEN.WBST@sri-unix (11/23/82)
Jeff, Why all the concern over speed of data transfer in the amateur service. Ham radio is supposed to be a hobby and as such should be relaxing and enjoyable. Life is too hurried nowadays as it is without putting rush-rush into the hobby. Slow down a little and enjoy life, don't burn out a bearing. Lou K2ANC
DGHESS.ES@sri-unix (11/23/82)
RIGHT ON, LOU.......
AS I MENTIONED BEFORE, AFTER A LONG DAY (I DRIVE 600 MILES A
WEEK TO & FROM WORK), I FOR SURE DO NOT WANT TO SPEED JAM ANY
KIND OF COMMUNICATION. CW FOR ME IS A NICE WAY TO HAVE A
RELAXING CONVERSATION WITH THE EXCITEMENT OF GETTING ANOTHER
STATE WITH MY HW-8 & INVERTED VEE.
SO THERE !!!!!
DONOVAN KA6SOJNBarbieri.es@sri-unix (11/23/82)
Seems to me that those interested in the true blue experimentism of the upper bands are not against the proposal. Then there are those who would not know what a handheld was if they tripped over it. Okay, fine. Everyone has their favorites. Gen
wmartin (11/25/82)
I am somewhat confused as to the traditional concept (i.e., I read it before somewhere more than once) of "bandwidth used = information transfer rate". Let me postulate this: A very slow CW signal is transmitted by generating an RF signal 100 Hz in bandwidth, switching it on and off once per second to make a second-long dit. This on-off switching speed is increased, assuming the transmitting and receiving equipment can handle and detect it, to ten times per second, then 100 times per second, then 1000 times per second. Instead of one-second dits, we now have one-millisecond dits, right? All along, the signal has been 100 Hz wide, because the SIGNAL has never been changed, all we have been doing is turning it on and off faster. So our information transfer rate has multiplied by a factor of 1000, but the bandwidth is unchanged. Couldn't this process continue, reducing the dit length to a microsecond, and then a nanosecond, until the pulses are so short that they cannot be distinguished from a continuous signal? The bandwidth is still unchanged, isn't it? Or is it some magic effect of the switching that turning something on and off at a higher rate will somehow increase the bandwidth it occupies? If it does, is this some effect like splatter? If so, isn't eliminating it just an engineering problem, not a theoretical issue? Hmmm... Will Martin
karn (11/25/82)
Envelope shaping in a CW transmitter places a limit on the speed at which it can be keyed with the dots remaining separable at the receiver. Envelope shaping is also what determines the bandwidth. In the extreme case, a CW transmitter that could generate distinguishable dots at 20,000 dots/second would be generating terrific "key clicks" even if keyed at a much slower rate. In order for a CW transmitter to take up the minimum possible bandwidth, its keying envelope would have to be changed as a function of the operator's sending speed. If the operator were to send slower, the rise/fall times of the transmitter envelope should be made longer, and the occupied bandwidth would decrease. Ideally, the envelope rise time should be adjusted so that the transmitter just reaches full power at the point where the key is released in a "dot", resulting in a sinusoidal envelope. Otherwise, bandwidth is being wasted by communicating the rise time of the envelope faster than it need be. The same effect is true in narrow CW filters for receivers. If one uses too narrow a filter (assuming the receiver remains stable), fast CW would come out as a blur. Any filter will spread out the rise and fall times of the signals passing through it. Phil Karn, KA9Q
michaelk@sri-unix (11/29/82)
Running CW at 0 w.p.m ideally gives you a bandwidth of zero hz (Awful clean, stable xmtr). When you key it, you are modulating it, producing sidebands. If you increase the w.p.m rate, the bandwidth increases. If your transmitter doesn't "waveshape" the keying action then the bandwidth increases much in the way the modulating square wave has a bandwidth wider than it's fundamental. At 20 w.p.m. (assuming suitable "waveshaping") the bandwidth is still under 100 Hz or so. By the way, bandwidth does not determine the information transfer rate, it only limits it. Human voices (like in SSB mode) are not efficient in bandwidth use. In the second I might say "hello", I could send 120 characters with my 1200 baud modem that uses the same (or smaller) bandwidth . It would take some three seconds to send that using CW at 20WPM, but at 1/25 the bandwidth, yielding a net 8 times better use of bandwidth. Further, sending English language by any mode also cuts down the information transfer rate -- English contains much redundancy. An obvious example of this is your *NIX "compact" program. You can make a text file 30% smaller WITHOUT loosing any information content (it can be converted back, can't it?). For more detailed, and exact numerical representations, get hold of a fellow "into" Coherent C.W. -- They operate with VERY narrow bandwidth, such that you can pull out copyable CW when you have a noise to signal ratio (>1). Mike Kersenbrock WB4IOJ Aloha, Or.
fayette.wbst@sri-unix (11/29/82)
BRAVO !!!!! TNX to you Jeff mike wb2fsi
Stephany.WBST@PARC-MAXC@sri-unix (11/29/82)
The bandwidth of a CW signal is 4 times the words per minute (5 letters/word not 4 letters/word as in Canada and England). As the information rate is increased the bandwidth goes up .... a law of physics and not a thing that can be eliminated. The confussion in these types of arguments is the fact that you mix the time and frequency domain. In the frequency domain there are only sidebands and carriers that never change in time. In the time domain there are only carriers that change in amplitude. The components in the frequency domain always add up to what you get in the time domain (fourier transform). In the case of CW the unvarying components in the frequency domain add up to a signal in the time domain that goes on and off. The components in the frequency domain do not go on and off when keyed. The frequency domain is what you get when you tune across a signal with a receiver of bandwidth much much less than the signal bandwidth. The time domain is what you get when you tune across a signal with a bandwidth much wider than the signal bandwidth. In reality we are always between the two. Usually you set your bandwidth to be just a little bigger than the signal so the output is in the time domain but not so much in the time domain that you get a signal you don't want. If a dit becomes a microsecond then the bandwidth is about two megahertz or a little more and you occupy two megahertz of spectrum. The FCC doesn't like that although the Germans did just this during WW2 in sending to their subs. They sent CW in a burst, recorded it and played it back at a low speed so the operator could copy it. The faster you switch on and off the wider the bandwidth. If you restrict the band width you lose information. In other words Shannon's formula: Signal bit rate/Bandwidth = log(base 2) (signal/noise +1) If you send more information you need more power or more bandwidth. This is a fundamental limit of nature for which there is, at present, no way of getting around. Joe N2XS
Stephany.WBST@sri-unix (11/29/82)
The people in favor of a code free licese have several arguments which I consider invalid. Some of these are: 1. CW is "Just another mode" and should not be forced on people that do not want to use that mode. If ham radio was like any other hobby then you are at liberty to do what you want. But ham radio is not. Its fundamental purpose is public service. We are using a national resource ... spectrum space. If its just to amuse ourselves then we could do anything. But The reason you have your licese is because it contributes to the good of the nation. In particular disaster communication. I cannot see how anyone that pretends to be contributing to the public service can call himself a radio operator without being able to send and receive CW. CW, on HF or UHF can get through under most adverse conditions. Recently a boating accident left a boat sinking on the Pacific near San Francisco. The mike was smashed in the accident but the guy knew CW because he had leaned it as an Eagle Scout many years ago. He was saved because a Ham operator that knew CW was listening on the CB band. Also CW has been sent by waving flags, flashing flashlights, tapping with pipes, etc.etc.etc. In a submarine disaster code was sent to the men inside and back by tapping a pipe ... one bang for dots, two bangs for dashes. Many lives have been saved because of a knowledge of CW both on and off the bands. Also, in times of disaster on a wide level, most communication is by written message. This can be more accurately and faster sent and received by CW. 2. CW is an unnecessary restriction and is just "too difficult to learn". It takes a person of average intelligence about 4 hours to learn and send and received at 5 WPM. After leaning the code it takes about 30 minutes practice to get to 5WPM. 3. CW is not necessary on the UHF bands. In the future it will even be more necessary. As the space shuttle builds a space station, exploration to the planets and beyond will take place. QSO's by hams will be at first by CW because of the simplicity and effectiveness. Also, emergency communication with people in space, via the Hams on Earth would be greatly hampered without CW. How would you feel if the first distress message from space was sent via CW and there were no hams that knew how to copy it ? Remeber that boating accident. Joe, N2XS (spark forever !!)
danny (11/29/82)
Yes, there is a theoretical reason why increasing the rate at which a "pure" RF carrier is turned on and off MUST increase its bandwidth. The branch of mathematics/engineering which makes this clear is Fourier analysis.
DGHESS.ES@sri-unix (11/29/82)
BRAVO, BRAVO !!!!!!!!!!!! I LOVE IT !!!!!! DONOVAN, KA6SOJ
neil (12/01/82)
#R:sri-unix:-432900:hplabs:5500001:000:2471 hplabs!neil Nov 30 19:07:00 1982 ***** hplabs:net.ham-radio / sri-unix!WBST / 9:34 am Nov 29, 1982 The people in favor of a code free licese have several arguments which I consider invalid. Some of these are: 1. CW is "Just another mode" and should not be forced on people that do not want to use that mode. If ham radio was like any other hobby then you are at liberty to do what you want. But ham radio is not. Its fundamental purpose is public service. We are using a national resource ... spectrum space. If its just to amuse ourselves then we could do anything. But The reason you have your licese is because it contributes to the good of the nation. In particular disaster communication. I cannot see how anyone that pretends to be contributing to the public service can call himself a radio operator without being able to send and receive CW. CW, on HF or UHF can get through under most adverse conditions. Recently a boating accident left a boat sinking on the Pacific near San Francisco. The mike was smashed in the accident but the guy knew CW because he had leaned it as an Eagle Scout many years ago. He was saved because a Ham operator that knew CW was listening on the CB band. Also CW has been sent by waving flags, flashing flashlights, tapping with pipes, etc.etc.etc. In a submarine disaster code was sent to the men inside and back by tapping a pipe ... one bang for dots, two bangs for dashes. Many lives have been saved because of a knowledge of CW both on and off the bands. Also, in times of disaster on a wide level, most communication is by written message. This can be more accurately and faster sent and received by CW. 2. CW is an unnecessary restriction and is just "too difficult to learn". It takes a person of average intelligence about 4 hours to learn and send and received at 5 WPM. After leaning the code it takes about 30 minutes practice to get to 5WPM. 3. CW is not necessary on the UHF bands. In the future it will even be more necessary. As the space shuttle builds a space station, exploration to the planets and beyond will take place. QSO's by hams will be at first by CW because of the simplicity and effectiveness. Also, emergency communication with people in space, via the Hams on Earth would be greatly hampered without CW. How would you feel if the first distress message from space was sent via CW and there were no hams that knew how to copy it ? Remeber that boating accident. Joe, N2XS (spark forever !!) ----------
jfw (12/02/82)
One more little bit of rambling on the subject, then I'll go away. I personally do use CW when I operate (not exclusively, but competitive with my phone usage). I do it for reasons varying between the fun of it and the fact that I got New York from Washington State with a 10 watt transmitter (on phone, it would have been significantly more difficult (NOT impossible)). If you want a way of using radio without knowing code, why must it be an "Amateur Radio License"? Why not a separate radio class for computer/digital packet phreaques? It seems that that might be the better thing to do (geez, some of the new bands could even be shared with UHF ham bands--it certainly won't be a totally new occurance). Blah, blah, blah... AR de WB7EEL/1 SK (I promise!) John Woods