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Radio913 wrote:
How does a capacitor reflect more power than you feed it? With an inductor in the circuit, the voltage on a capacitor can be greater than the source voltage. Consider the following series resonant circuit. What are the voltages on the cap and coil at resonance? 100W source========1wl feedline===cap===50 ohm===coil -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Mon, 22 Sep 2003 22:49:22 -0500, Cecil Moore
wrote: So what? Hi Cecil, Exactly, you don't have a clue by how much do you? 73's Richard Clark, KB7QHC |
On Tue, 23 Sep 2003 07:24:12 +0100, "Ian White, G3SEK"
wrote: Richard Clark wrote: Hi Ian, A Directional Coupler consists of two transmission lines. You say that after cutting out all the examples that I gave of directional couplers that don't. There is NO material difference offered in your original to merit its inclusion in the first place. Transmission Lines are the media through which B/H waves migrate inexorably fixed together. The premise (which you alone bring as a clouded presumption) that the Bruene bridge somehow works with independence from this is simply a convenience in discussing its operation, a convention of discussion at best and not a reality. The waves migrate along the *main* transmission line - and obviously every directional coupler has to contain one of those. But many do not contain any secondary transmission line, in any realistic physical sense of that term. Ian, you exhibit a whole lack of experience into the matter. There are more such examples of Directional Couplers that fit the most precise definition of transmission line than not. Those that do not (your Bruene bridges) are simply lumped equivalents that still maintain classic formalisms that observe all the strictures of wave mechanics. That they can be described by simpler metaphors does not diminish either their utility, nor their intellectual purity. Your rejections of their application are preposterous examples of pedagogical minutia. 73's Richard Clark, KB7QHC |
Cecil Moore wrote in message ...
Radio913 wrote: How does a capacitor reflect more power than you feed it? With an inductor in the circuit, the voltage on a capacitor can be greater than the source voltage. Consider the following series resonant circuit. What are the voltages on the cap and coil at resonance? 100W source========1wl feedline===cap===50 ohm===coil Is that a 50 ohm resistor? And where is the ground? Could you re-draw this, Cecil? I was hoping Keith would measure the end of the inductor with the cap removed, so we could get an idea of the incident voltage wave. Slick |
Richard Clark wrote of:
preposterous examples of pedagogical minutia. Eschew sesquipedalianism! -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek |
Newton may not have been EXACTLY right but he had a damned near-enough
practical approximation. Much better than a rough-and-ready Bird. |
Radio913 wrote:
You never measured the incident voltage. And you refused to measure the end of the inductor, with the capacitor removed (even with the 15 pF, it should tell us something about Vi). I have done my lab work and produced results consistent with classic rho. You have not accepted my results, possibly because they are inconsistent with your world view. It is now your turn to hit the lab. You will, barring error, obtain results consistent with mine. You will be able to measure any parameter you wish, even do other experiments, and you will find the results are always consistent with classic, not revised rho. The benefit of going to the lab is all yours. You will learn how it works. Alternatively, perhaps, you will demonstrate that classic rho is all wrong and revised rho rules. In this case, if YOU have done the lab work, YOU will get (and deserve) all the glory of a major revision to transmission line theory. If I went back to the lab you are unlikely to accept any new results from me any more than you have accepted those to date. Sometimes seeing is believing. .......On the other hand, perhaps you can convince me. Predict what the measurement will be and what it will mean. Tell me how you did the prediction. And allow some error bounds. Say we assume the probe is between 15 and 30 pf. Then we'll see. This may be true, but are you saying that a capacitor can reflect an RMS voltage wave that is greater than the one that charges it? Yes indeed. Resonant circuits achieve this with ease. ...Keith Absolutely incorrect! If capacitance is defined as Coulombs/Volt, then how are you getting more coulombs than you put in? Remember, i said Root Mean Square voltage. How does a capacitor reflect more power than you feed it? It's almost time for me to cut out of this discussion, if you still don't understand me. I can only suggest that you go to the lab. Given your statements above, there is a great opportunity for hands on learning here. ....Keith |
Dr. Slick wrote:
Cecil Moore wrote in message ... Radio913 wrote: How does a capacitor reflect more power than you feed it? With an inductor in the circuit, the voltage on a capacitor can be greater than the source voltage. Consider the following series resonant circuit. What are the voltages on the cap and coil at resonance? 100W source========1wl feedline===cap===50 ohm===coil Is that a 50 ohm resistor? And where is the ground? Yes, a 50 ohm resistor. No ground, it is a balanced system. Note the two parallel wires. Could you re-draw this, Cecil? Sigh ... +------1WL feedline--(-j500)--+ | | 100W source (50+j0) | | +------1WL feedline--(+j500)--+ -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Reg Edwards wrote:
Newton may not have been EXACTLY right but he had a damned near-enough practical approximation. What was his approximation for the orbit of Mercury? :-) -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
wrote:
power = volts * amps = (Vfwd + Vref) * (Ifwd + Iref) = Vf*If + Vf*Ir + Vr*If + Vr*Ir Seems you've lost a couple of terms in there. This is why, in general (using my definition of general), superposition does not hold for power. Those extra terms get in the way. I suspect that Vf*Ir and Vr*If have absolutely no physical existence. Light waves traveling in opposite directions have no effect on each other. Why should RF EM waves traveling in opposite directions have any effect on each other? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
wrote: May I suggest that if you had read the posting to which I responded and the rest of my response you would have found exactly the example you are looking for: the forward voltage and current on a transmission line when a standing wave is present (and the reflected as well). How did the standing wave get there in the first place? *POWER* from the generator. You simply cannot have standing waves without a power source, a forward wave, and a reflected wave. You are asking us to completely ignore the cause of standing waves. It is not obvious to me how you extrapolate my postings to these outrageous assertions. For sure there is power from the generator. It is needed to charge the line and to provide whatever power is consumed in the load and line losses. When a standing wave is present, for sure there is a forward and reflected voltage and current wave. After all it is called a voltage standing wave. But these voltage and current forward and reflected waves do not have power. They are exactly the same as the voltages computed using superposition in circuit analysis, they are superposed in exactly the same way to find the resultant voltage, and it is illegal, except in special cases, to assume that these constituent voltage terms represent power. May I suggest, for clearer understanding, that just for a few moments (say 30 minutes), you set aside RF and consider how a line is charged by a step function. Do the voltage and current reflection diagrams. And then consider the energy flow just in front and just following the voltage step as it propagates down the line and back and down and back... Take the time to do this for the following cases... - matched generator - line terminated in Z0 - line open - line shorted After the line has charged consider what happens when the generator voltage is set back to 0. Do it all again for a mismatched generator. Then for a charged open termination line, consider what happens when a load of Z0 is applied. And then when the load is removed. For each of these cases determine how the voltage fronts propagate, the energy flow in front of and following the step, the resulting energy distribution on the line and whether this energy is stored in the capacitance or inductance or H field or E field. Because of the step function excitation, none of these computations are difficult. With this example it is easy to see when energy is flowing and when it is not, and contrast this to the energy flows computed using the forward and reflected voltages. Well maybe the above is more than 30 minutes, but there is much to be learned from a thorough understanding of the behaviour with this simple excitation. Now replace step excitation with sinusoidal; the principles are the same, but the computations are more complex and the resulting voltage and energy distributions on the line are more interesting. But the fundamentals are the same. The above thought experiment was the one that made clear to me the fallacy of assigning power to the forward and reflected voltage waves. So there is some risk for you doing this thought experiment; the results may conflict with some of your deeply held beliefs. It is a risk worth taking. ....Keith |
"Ian White, G3SEK" wrote:
Keith wrote: [...] in general (using my definition of general) [...] in general (using my definition of general) [...] in general (using my definition of general) [...] in the general case (using my definition of general) You don't have to be defensive about this, Keith - you're on solid ground. In this discussion, where we're trying to be scientific, you are using the word in the correct *scientific* sense, meaning "in all cases." Cecil is using it in a different and looser sense, meaning "in common cases." "General" is just another of those words like "theory" where the scientific usage and regular conversational usage are almost completely opposite. Yes, indeed, 'general' is one of those words with multiple mutually inconsistent meanings. My dictionary gives seven definitions for the adjective form and they alternate between meanings which 'include all' and those which 'include most'. ....Keith |
wrote:
But these voltage and current forward and reflected waves do not have power. The source puts out power. If that energy doesn't go into the forward and reflected waves, where does it go? I am not going to do any of your thought experiments until you stop ignoring the questions I previously asked you about mine. 100W source---one second long 291.4 ohm lossless line----50 ohm load During steady-state, the transmission line contains 300 joules that have not made it to the load. Where did that 300 joules go? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil More wrote:
wrote: Cecil Moore wrote: power = volts * amps = (Vfwd + Vref) * (Ifwd + Iref) = Vf*If + Vf*Ir + Vr*If + Vr*Ir Seems you've lost a couple of terms in there. As with any other math model, the negligible secondary terms are dropped. If the phase angle above is close to 90 degrees, two terms drop out. A Bird wattmeter assumes that two of the phase angles are close to 90 degrees. If they are not, you are using the wrong instrument for your measurements, a common problem. So again, it works in the specific, but not in the general case. Does this mean that forward and reverse waves only have power in the special case of low-loss feedlines? It means that if you use a 50 ohm Bird wattmeter in any environment except a 50 ohm one, you are using the wrong instrument. The answer appears orthogonal to the question. With my model, incident and reflected VOLTAGE waves and CURRENT waves do exist. This is in common, I think, with most authors on the subject. And this all works fine since superposition holds for voltage and current. It certainly doesn't work with your assertion that reflections don't exist. Go back 3 sentences and re-read "reflected VOLTAGE waves and CURRENT waves do exist". I think you were quoting from something I wrote. Your math model would have us believe that a power source pumps energy into voltage and current waves only to have that energy disappear from the universe for a time that is convenient for your math model. Of course, that very energy is magically created once again at the load. We've heard this bad magician's trick before. "Close your eyes while I make this elephant disappear." I am unsure how you extrapolate this from my writings. To recap. Everything with the incident and reflected wave model works as long as you stick to voltage and current waves. It is only when extended to include power (as done by Bird and others), that the model starts to deteriorate. For a resistive 50 ohm environment, the model does not deteriorate. The Bird is designed for such an environment. There doesn't exist any real-world instrument that will measure anything and everything. Every real-world measuring instrument has limitations. If you attempt to use a Bird in a 100-j100 ohm environment, that is your problem, not Bird's. So you are agreed: The reflected POWER model does not work in general. So to get the right answers in the general case (using my definition of general), compute your forward and reverse voltages and currents. Use superposition to derive the resultant voltages and currents at any point on the line and then use p(t) = v(t) * i(t) to compute the power, which you may then average if you desire. We've already been down this road but here it is, once again. Consider a one second long lossless feedline with an SWR of 5.83:1 and a Z0-matched source of 100 watts. After steady-state is reached, the feedline contains 300 joules of energy which cannot stand still. A Bird wattmeter reads 200w forward and 100w reflected. Your power calculation gives 100 watts everywhere implying that there are only 100 joules in transit in the feedline. No. You have made an incorrect implication. 100 watts flowing says nothing about how much energy is stored. What happened to the other 200 joules pumped into the system by the source during the transient state? Hint: there is 100 joules in the reflected waves and 100 joules in the re-reflected waves. The Bird is correct. Your experiment appears to be incompletely or incorrectly specified. If the source is Z0 matched to the transmission line, how did you get a re-reflected wave at the source? ....Keith |
Newton may not have been EXACTLY right but he had a damned near-enough
practical approximation. What was his approximation for the orbit of Mercury? :-) ====================== In MY thermometer mercury does not rotate - it just goes up and down. According to Bush it's something to do with apple trees. --- Reg |
And then consider the energy
flow just in front and just following the voltage step as it propagates down the line and back and down and back... ======================= Kelvin had trouble with voltage steps when trying to predict signalling speed on the first Atlantic telegraph cable. They went ahead, chartered the Great Eastern steamship, steamed West and laid the thing anyway. Shortly afterwards it broke. Kelvin was created a Lord for his un-finished services and had a bridge named after him. But it was indeed a difficult problem in that day and age. Twenty years later, hard-of-hearing Heaviside invented a brand new branch of mathematics, the Operational Calculus, to solve that particular, and a great number of other problems. For HIS services to mankind, as a revolutionary, he was derided by the pompous Establishment whose members resorted only to plagiarised text books. Heaviside only had a Layer named after him. To their own credit, it was American communications engineers who eventually acknowledged his genius. But then, Americans always did have sympathetic feelings towards revolutionaries. What amazes me is the amount of trouble some modern American engineers still appear to suffer from on the subject of propagation of an electric current along a pair of wires. Wires have been around a long time now. Instead of thinking in terms of frequency and waves why not do as Oliver did and try time and waveshape. It worked for him. Exactly what, where and when is being reflected becomes clear. And if anybody enjoys playing with numbers just replace 'j-omega' with 's' (It was 'p' when I first played with it.) Incidentally, the concept of wire-gauges originated in my home city, Birmingham, England. Faraday was familiar with it. It was internationally known as the BWG. The Americans, just to be different, changed theirs to AWG. Now (nearly) everybody has gone metric. ;o) ---- Reg, G4FGQ |
Reg, G4FGQ wrote:
"Instead of thinking in terms of frequency and waves why not do as Oliver did and try time and waveshape?" The digital revolution is well underway and Reg has the right idea. Radio is the domain of frequency and waves however. Terman`s first words: "Electrical energy that has escaped into free space exists in the form of electromagnetic waves." are still true. Step functions lost interest with the demise of telegraph, but ones and zeros are back bigger than ever. Best regards, Richard Harrison, KB5WZI |
On Tue, 23 Sep 2003 11:15:42 +0100, "Ian White, G3SEK"
wrote: Eschew sesquipedalianism! Gesundheit. |
Richard Clark wrote:
What is the V/I for a 1 degree rise? Same as before, Richard, dissipative. This is a binary measurement. The possible values are dissipative and non-dissipative. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Tue, 23 Sep 2003 10:54:20 -0500, Cecil Moore
wrote: Uh Keith, *NO* instrument works in the general case. Can you measure gamma rays with your RF voltmeter? On Tue, 10 Jun 2003 18:47:32 -0500, W5DXP wrote: Richard Clark wrote: Do you measure V/I with a thermometer? One certainly can. If there's no temperature rise, the resistance value is dissipationless. Hi Cecil, What is the V/I for a 1 degree rise? 73's Richard Clark, KB7QHC |
On Tue, 23 Sep 2003 11:15:35 -0500, Cecil Moore
wrote: Richard Clark wrote: What is the V/I for a 1 degree rise? Same as before, Richard, dissipative. This is a binary measurement. The possible values are dissipative and non-dissipative. Hi Cecil, Binary hmmm? So you say you experience 1 V/I for a 1 degree rise? Or is it 0 V/I for a 1 degree rise? Curious sort of general instrumentation you have there. What is the name of this superb instrument of yours? 73's Richard Clark, KB7QHC |
Richard Clark wrote:
wrote: Same as before, Richard, dissipative. This is a binary measurement. The possible values are dissipative and non-dissipative. Curious sort of general instrumentation you have there. What is the name of this superb instrument of yours? Did you ever grab the top of a 75m hamstick coil right after transmitting? That coil is dissipative. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Tue, 23 Sep 2003 12:29:46 -0500, Cecil Moore
wrote: Did you ever grab the top of a 75m hamstick coil right after transmitting? That coil is dissipative. Hi Cecil, So this general instrument you use is your hand? Lest we forget: On Tue, 23 Sep 2003 10:54:20 -0500, Cecil Moore wrote: Uh Keith, *NO* instrument works in the general case. Keep your hands to yourself. ;-) 73's Richard Clark, KB7QHC |
There are a lot of TDR and oscilloscope users out there to contradict that.
Roy Lewallen, W7EL Richard Harrison wrote: . . . Step functions lost interest with the demise of telegraph, but ones and zeros are back bigger than ever. Best regards, Richard Harrison, KB5WZI |
On Tue, 23 Sep 2003 12:29:46 -0500, Cecil Moore
wrote: Did you ever grab the top of a 75m hamstick coil right after transmitting? That coil is dissipative. Hi Cecil, On even more reflection, your hand is an abysmal binary general instrument. Take your own test above. What was the V/I? You don't know. What was the temperature? You don't know. Could you measure 1W dissipation? You don't know. Could you determine 1 Ohm? You don't know. Could you determine 1°? You don't know. How accurate could you if you deny these above? (Binary measures are either totally wrong or half-assed right.) What was the V/I to within 5ppm? You don't know. How about to within 50%? You still don't know. Step outside (without recourse to weather report or thermometer) and touch a sun exposed wall of your home. What temperature is it to within 1°? How much error did your hand introduce in cooling/warming it up/down? You haven't a clue. No wonder you reject general instrumentation application, you make miserable choices. You cannot even offer quantitative evidence, merely the Zen of "oooh that's hot," and you don't even suggest that. How long before you ride your bike to the library anyway? Waiting for a hot/cool/just-right day? Call ahead to see if "Goldilocks" is not already checked out before leaving. 73's Richard Clark, KB7QHC |
Richard Clark wrote:
So this general instrument you use is your hand? Yep, hands are generally quite useful. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Clark wrote:
On even more reflection, your hand is an abysmal binary general instrument. You are perfectly free to live your life in the no-hands mode. Myself, I find them generally quite useful for binary decisions. All one needs is a trigger threshold. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Tue, 23 Sep 2003 14:22:39 -0500, Cecil Moore
wrote: Richard Clark wrote: On even more reflection, your hand is an abysmal binary general instrument. You are perfectly free to live your life in the no-hands mode. Myself, I find them generally quite useful for binary decisions. All one needs is a trigger threshold. Hi Cecil, And you haven't the faintest idea what that threshold is except for "ouch." Given your tender sensibility, one might be convinced by you that a glass standing in the shade would boil water. "Might." I take it by your lack of other response you couldn't summon up a simple measure of temperature, power, resistance, much less their accuracy with your instrument. How much power in 10 OuchWatts? 73's Richard Clark, KB7QHC |
Richard Clark wrote:
I take it by your lack of other response you couldn't summon up a simple measure of temperature, ... If you, as a father, ever felt the brow of your child, you can tell his/her body temperature within a couple of degrees. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Tue, 23 Sep 2003 17:35:50 -0500, Cecil Moore
wrote: Richard Clark wrote: I take it by your lack of other response you couldn't summon up a simple measure of temperature, ... If you, as a father, ever felt the brow of your child, you can tell his/her body temperature within a couple of degrees. Hi Cecil, A couple of degrees? Another way of saying you don't know. Step outside, and touch the side of the house illuminated by the sun and tell me within a couple of degrees what its temperature is. You don't have a clue. All of this means that you are long on wind when it comes to claims, and short on real facts when it comes to application. Just like your gusting on about light (like the sun) and wholly lost in the woods when asked how much power (like the temperature asked here). You couldn't even guess without fear of embarrassment. Want to jack up the pressure? How many Watts in that same area where your hand feels the heat against the sun drenched wall? You claim you can do it with your hand and a 75m hamstick coil (just a claim - and pretty inspecific at that), but have failed repeatedly to divulge the exact same ability with the sun against your own house. To this point the best you have to offer in the Texan sun is that it is out: 0 - maybe not 1 - maybe so If this is the best of your generalization (a binary shrug of the shoulders), you certainly could achieve a leap of success in dropping your poor standard equipment. 73's Richard Clark, KB7QHC |
I have done my lab work and produced results consistent with
classic rho. But Classic rho didn't tell us the incident voltage. Also, the crux of your argument was that rho= -1 should be a short, which it is not for complex Zo. The benefit of going to the lab is all yours. You will learn how it works. Alternatively, perhaps, you will demonstrate that classic rho is all wrong and revised rho rules. In this case, if YOU have done the lab work, YOU will get (and deserve) all the glory of a major revision to transmission line theory. This is not a revision. This is already in the published material. And i have plenty of lab experience, thank you very much. If I went back to the lab you are unlikely to accept any new results from me any more than you have accepted those to date. Sometimes seeing is believing. Right. And you probably won't accept any new data from me. This may be true, but are you saying that a capacitor can reflect an RMS voltage wave that is greater than the one that charges it? Yes indeed. Resonant circuits achieve this with ease. ...Keith Absolutely incorrect! If capacitance is defined as Coulombs/Volt, then how are you getting more coulombs than you put in? Remember, i said Root Mean Square voltage. How does a capacitor reflect more power than you feed it? It's almost time for me to cut out of this discussion, if you still don't understand me. Slick |
It's NOT very easy to tell that your two diagrams are the same, Cecil!
At any rate, at resonance, the reactances should cancel out, and the 50 ohms should be left. Slick |
Richard Clark wrote:
All of this means that you are long on wind when it comes to claims, ... What is it that you think I have claimed? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Radio913 wrote:
It's NOT very easy to tell that your two diagrams are the same, Cecil! At any rate, at resonance, the reactances should cancel out, and the 50 ohms should be left. Is the voltage across the capacitor higher than the source voltage? Is the reactive power on the capacitor higher than the source power? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Tue, 23 Sep 2003 20:19:18 -0500, Cecil Moore
wrote: Richard Clark wrote: All of this means that you are long on wind when it comes to claims, ... What is it that you think I have claimed? Hi Cecil, Well you've never claimed to have any sort of attention span. On Tue, 10 Jun 2003 18:47:32 -0500, W5DXP wrote: Richard Clark wrote: Do you measure V/I with a thermometer? One certainly can. If there's no temperature rise, the resistance value is dissipationless. Hi Cecil, What is the V/I for a 1 degree rise? 73's Richard Clark, KB7QHC I suppose if you gust on enough, there is no temperature rise in your mind. Talk about air cooled resistors. You can keep your hands in your pockets. 73's Richard Clark, KB7QHC |
Richard Clark wrote:
I suppose if you gust on enough, there is no temperature rise in your mind. My mind remains at a fairly constant 99.2 degrees F. Somewhere in my pile of junk is a device that measures the temperature of an IC. The last time I used it was last century on a 4:1 voltage balun in AZ. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Roy, WtEL wrote:
"There are a lot of TDR and oscilloscope users out there to contradict that." (Step functions lost interest with the demise of telegraph, but ones and zeros are back bigger than ever.) Lord Kelvin, William Thomson suggested in the 19th century that life may have arrived here from outer space. He died in 1907. Do you suppose he was using TDR with an oscilloscope to determine subsea cable faults? Best regards, Richard Harrison, KB5WZI |
Cecil Moore wrote in message ...
Richard Clark wrote: I suppose if you gust on enough, there is no temperature rise in your mind. My mind remains at a fairly constant 99.2 degrees F. Somewhere in my pile of junk is a device that measures the temperature of an IC. The last time I used it was last century on a 4:1 voltage balun in AZ. Wow Cecil, yours was the only posting on this thread on Sunday which is considerably down from the last months massive offerings. Is it possible that all is now known about this subject? Is it a case of saying the same things over and over again is exhausting all. I must admit that I understand little if anything about the subject but I must say I am pleased that the group has returned to the mundane subject of antennas even tho some may regard it as dumbing down the subject. Hopefully this subject is so now well understood your paper will be accepted by somebody and the subject can then be barred for all time by the ARRL. Have a happy day Art |
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