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"Roy Lewallen" wrote in message ... Richard Fry wrote: . . . The source impedance of most transmitters is not published even today. If it was, probably we wouldn't be having all of this confusion about it, and its effects. Who's confused? It has no effect. Roy Lewallen, W7EL Hi Roy, Going back to the Slick discussions of last winter, Was that you who made the statement that you can have 100% re reflection from a transmitter, even if it has a 50 Ohm output impedance? At first I thought this was all wet, but after making some low power experiments, I am convinced it is true. Tam/WB2TT |
"Richard Harrison" wrote I`d design for a conjugate match at the rated load and include overload protection for an output short circuit or near short. For solid-state I`d provide overvoltage protection.in addition to overcurrent protection. =================================== To obtain a conjugate match it is first necessary to know what the source impedamce is. How or from where is that elusive figure obtained? It is not given in a transmitting tube manufacturer's data sheets. Perhaps it doesn't matter what it is - not needed? ---- Reg, G4FGQ |
Walter Maxwell wrote:
Thus, no transmission line is necessary. For example, the device can be connected directly to the antenna terminals, or any other device you desire to determine the mismatch, and power it directly from the signal source--no transmission line is needed on either port for the device to indicate the degree of mismatch. Assume a 100+j100 ohm load and a 100-j100 ohm transmitter directly connected with no transmission line. The system is matched. Are there any reflections? Now install a transmission line. Will an SWR meter read the same thing in both cases? -- 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:
And the accuracy of any instrument depends on how it is used rather than on what the manufacturer says about it. Presumably, including the "Bird wattmeter" and "SWR meter". :-) -- 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! =----- |
Tam/WB2TT wrote:
Going back to the Slick discussions of last winter, Was that you who made the statement that you can have 100% re reflection from a transmitter, even if it has a 50 Ohm output impedance? At first I thought this was all wet, but after making some low power experiments, I am convinced it is true. It is true by definition. All reflected power incident upon a transmitter is re-reflected, by definition. Never mind that reflected voltage can cause an over-voltage condition and/or reflected current can cause an over-current condition *inside* the transmitter. By definition, any reflected power dissipated in the source after making a round trip to the load was never generated to begin with. -- 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! =----- |
Ian Jackson wrote:
Call it an RLR meter, which is what it IS really measuring. How about an "SVI", Superposed Voltage-sample(+/-)Current-sample, named for the math function that it is performing? -- 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:
To obtain a conjugate match it is first necessary to know what the source impedamce is. How or from where is that elusive figure obtained? If no reflections are allowed to reach the source, the source impedance doesn't matter (except maybe for efficiency). It is not given in a transmitting tube manufacturer's data sheets. Perhaps it doesn't matter what it is - not needed? Install a matching network that achieves a quasi-conjugate match between the network and the load. That's what I do. :-) -- 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, 6 Sep 2004 06:20:23 -0500, "Richard Fry"
wrote: I won't try to soften this Hi OM, I kin take it ;-) : your conclusion above doesn't just _appear_ to be wrong, it IS wrong. 100% wrong. Hmmm, in light of what is about to be said by you this continues to be amusing. How do I know? I was the author of all of the brochures and technical data sheets for Harris' entire FM product line for the ten years before I retired. Yes, your patter sounds like a publicist rather than a design engineer - I've snipped your commercial fluff as it is pretty soft still. It is designed for a 50 ohm load. Imagine THAT! Of course I won't hold my breath for your explanations WHY (or -gasp- how) it is designed for 50/75/100/300 Ohms and not just slap the output into any load - that would be an engineering issue of matching which seems to be foreign to your discussion. Glad to see my inclusions of so much of your copy brought back you memory that rejected this: On Sun, 5 Sep 2004 11:25:02 -0500, "Richard Fry" wrote: The source impedance of most transmitters is not published even today. I can accept that perhaps under your hand it was not, but Harris has returned to the fold of conventional design specifications: MW-10B SPECIFICATIONS RF OUTPUT IMPEDANCE: 50 ohms, unbalanced. Other output impedances available on special order. Harris Platinum Z FM transmitter 100 ohm output impedance (unbalanced) HARRIS SW-50 A RF Output Impedance 300 ohms balanced, 2.0 to 1 maximum VSWR Don't bother rummaging up you own drafts lingering in the musty corners of the web, there are newer spec sheets available that easily eclipse you in numbers to the contrary, but typical engineering regards for specifying the output impedance. I would suggest you review the works of a real engineer, Geoff Mendenhall (you know, the guy you dissed) who explicitly offers formula and specifications that correlate to current Harris equipment design considerations for matching source Z to load Z. This has been fairly common material available from Terman (One of Geoff's references) for 70 years now and even the digital age has not changed this: It sounds pretty simple, in fact, each module has a torroid (coil) which is the load for that module; all those torroids are lined up and an iron pipe is run through these torroids so that the combined output of all the modules is coupled into this pipe. One end of the pipe is at ground, the other end is the RF output of the transmitter. There is an output network to match impedance of the pipe, which is probably only a few Ohms, to the required output impedance which is usually 50 Ohms, although sometimes high power transmitters are set up to provide 75 Ohms, once in a while even 300 Ohms, to drive an open wire type transmission line system. From the Goatman: "It was necessary to determine the plate load impedance (formula) = 1000 Ohms where Emin min drop across the tube in saturation I1 ac plate current. "Since this Zp was to be coupled into a Z output of 50 Ohm, a impedance transformation of 20:1 was needed." Perhaps this is too many words for the publicity department style sheet, but to engineers there isn't an iota of difference in the design considerations of the final over the course of 1968-2004. It goes much further back than this - we will skip that so as to not appear to be roughing the receiver. However, to this subject I am quite used to the rebuttal "You are not going to change my mind." Impeccable logic such as this and variations offered by you have scant foothold in the sweep of time. I especially enjoy the sharp swerves to avoid the Goatman's simple expression above. Reminds me of the Chinese contortionist acts that used to be the staple of the Ed Sullivan show. 73's Richard Clark, KB7QHC |
On Mon, 06 Sep 2004 11:11:56 -0500, Cecil Moore
wrote: Reg Edwards wrote: And the accuracy of any instrument depends on how it is used rather than on what the manufacturer says about it. Presumably, including the "Bird wattmeter" and "SWR meter". :-) Not if you are measuring mud (data missing) |
Richard Clark wrote:
Cecil Moore wrote: Presumably, including the "Bird wattmeter" and "SWR meter". :-) Not if you are measuring mud (data missing) And I have indeed measured mud. -----= 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, 6 Sep 2004 10:01:15 +0000 (UTC), "Reg Edwards"
wrote: "Walter Maxwell" wrote If you question my statements above see the data from my measurements using professional grade instruments in either QEX, May/Jun 2001, Chapter 19 in Reflections II, ============================ The accuracy of measurements depends on who uses the instruments rather than on what the manufacturer says in his sales catalogue. I'd much prefer just to take your word for it, Walt. The manufacturer's type number is superfluous - it sounds like a gratuitous advert. ---- Reg, G4FGQ Thanks for the compliment, Reg, that you prefer to take my word for it. However, the reason we include the manufacturer is not as a gratuitutous advert, but to distinguish between the Cadillacs (Hewlett-Packard and General Radio, among a few others) and the non-descripts. The Cadillacs are professional, precision instruments, which, when used by knowledgeable people, provide data that can be relied upon. Without knowledge of the quality of the measuring device the reader is justifiably suspicious of the data. Walt |
On Mon, 6 Sep 2004 14:44:03 +0000 (UTC), "Reg Edwards"
wrote: "Richard Harrison" wrote I`d design for a conjugate match at the rated load and include overload protection for an output short circuit or near short. For solid-state I`d provide overvoltage protection.in addition to overcurrent protection. =================================== To obtain a conjugate match it is first necessary to know what the source impedamce is. How or from where is that elusive figure obtained? It is not given in a transmitting tube manufacturer's data sheets. Perhaps it doesn't matter what it is - not needed? ---- Reg, G4FGQ I guess I'll have to repeat it for emphasis, Reg, but if the drive level is set so that when the tuning and loading of the pi-network is adjusted to deliver the maximum available power is within the normal operating range, there is a conjugate match. In this condition the source and load impedances are equal. This condition is by definition and proved by measurements. If you like I'll send you a copy of the test procedure and the data. Walt |
On Mon, 6 Sep 2004 06:51:01 -0500, "Richard Fry" wrote:
"Walter Maxwell" When I bought the tx for new BC stn WCEN in 1948 it was from Gates Radio in Quincy. Is it possible that Geoff's business is a spinoff from Gates? Yes, Harris-Intertype (later just "Harris Corp") bought Gates Radio, lock, stock and barrel -- not a spinoff. Don Peterson, developing the use of TDR for finding discontinuities in RF feed lines for TV. He developed a kit for use in the field for locating ghost problems in the lines connecting the tx to the antenna. Were you aware of Don's work in this area? Vaguely. My primary contact and mentor was Dr Matti Siukola, lead engineer at RCA's antenna lab and test range at Gibbsboro, NJ. Under his direction I was responsible for updating and improving the VHF and UHF RF pulse test sets used by RCA Field Service. RF At the RCA Labs antenna lab Dr. Siulola's name was held in reverence, but I never had the opportunity to meet him. After initially being at the RCA Labs antenna lab I originated the antenna lab at the new RCA Labs spinoff division, the Astro-Electronics Div, which produced the world's first weather satellite, TIROS 1, of which I developed the entire antenna system. However, I began that development at the RCA Labs antenna lab prior to the AED spinoff. I was working there along with Jess Epstein, of the Brown, Lewis, and Epstein group who performed the ground radial experiment that set the FCC standards for radials that still exist today. I also spent time at the Moorestown antenna lab, working on the development of the Lunar Rover dish antennas. On its finish I performed all the final pattern, gain, and ellipticity measurements prior to shipping them to NASA. Walt |
On Mon, 6 Sep 2004 10:39:54 -0400, "Tam/WB2TT" wrote:
Hi Roy, Going back to the Slick discussions of last winter, Was that you who made the statement that you can have 100% re reflection from a transmitter, even if it has a 50 Ohm output impedance? At first I thought this was all wet, but after making some low power experiments, I am convinced it is true. Tam/WB2TT Yep , Tam, it's correct. The internal resistance in Class B and C amps has two parts, 1) the cathode-to-plate resistance, which is dissipative, and 2) the non-dissipative resistance established by the V/I ratio within the pi-network tank circuit--a high resistance at the input and a low resistance at the output. The V/I ratio also establishes the slope of the load line. Consequently, the reflected power reaching the network output is not absorbed, but instead adds to the power delivered by the generator. Although powers are not generally considered to add, they do in this case, because their respective voltage and current phasors add. If the reflected voltage and current phasors are not in phase with those from he source, the only result is that the source is mismatched to the load and reduces its delivery of power. Readjusting the tuning and loading controls brings the out-of-phase phasors in phase, establishes a conjugate match and the source again delivers the maximum available power. Walt, W2DU |
On Mon, 6 Sep 2004 10:39:54 -0400, "Tam/WB2TT" wrote:
Tam, would you please send me your email address? I want to send you a copy of two new chapters from Reflections III. I have reason to suspect your email shown above is not correct for email. Walt |
On Mon, 06 Sep 2004 18:41:37 GMT, Walter Maxwell wrote:
[snip] |Thanks for the compliment, Reg, that you prefer to take my word for it. However, |the reason we include the manufacturer is not as a gratuitutous advert, but to |distinguish between the Cadillacs (Hewlett-Packard and General Radio, among a |few others) and the non-descripts. The Cadillacs are professional, precision |instruments, which, when used by knowledgeable people, provide data that can be |relied upon. | |Without knowledge of the quality of the measuring device the reader is |justifiably suspicious of the data. Careful Walt. Reg is an Englishman, he doesn't know what at Cadillac is, other than an American automobile, which makes it suspect. You should use Jaguar for comparison. Uh oh, better not, that is an American company (Ford). Alright, how about Aston Martin. Darn, another Ford. I've got it; Rolls-Royce! Nope, that's a German car (BMW). Okay maybe a Bentley. Nooo. That's a Volkswagon. Surely a Land Rover. Not again! Another Ford. You're right. HP and GR were the Cadillacs of the industry. [g] |
On Mon, 6 Sep 2004 06:20:23 -0500, "Richard Fry"
wrote: How do I know? I was the author of all of the brochures and technical data sheets for Harris' entire FM product line for the ten years before I retired. That any published value of impedance applied to the load impedance expected was/is universal across the product lines: AM/FM/TV. Hi OM, If you simply follow the reference trail of those trade publications (the design guides used by the engineers who did the actual work) you would find PLENTY of source Z discussion: from Harris White Paper: "High Linearity RF Amplifier Design" referencing "Advances in AM Modulation Techniques to Improve Digital Transmission of HD Radio and DRM" "The poor antenna match will create a significant ripple in the transfer characteristic of the main power amplifier. If that amplifier itself has a poor output match to 50 Ohms [the succeeding discussion gets into the inability of feed forward correction to accommodate to this condition and the introduction of an expensive isolator and lowered efficiency] .... Alternatively, the amplifier itself could be modified to improve its output match." From Harris White Paper: "Improving Efficiency With Split-Level Combining" referencing "High-Linearity RF Amplifier Design" (op. cit.) and "RF Power Amplifiers for Wireless Communications" ppg. 31-32, 110 Discussion of load pulling to determine the "source impedance." pg. 99-103 , Figures 4.21 & 4.23 Discussion of the source transformation from source Z 4 Ohms to load Z 50 Ohms. Amplifier exhibits an 78% efficiency. and "Feed Forward Linear Amplifiers" "Frequency ripple is one of the principle factors that limit broad band signal cancellation and hence feed forward performance." .... "As previously discussed, to prevent loss of power due to impedance mismatches the input and output impedance of a device should be equal to the characteristic impedance (e.g. 50 Ohms) of the source and load to which it is connected." From Harris White Paper: "REDUCING FM IBOC TRANSMISSION COSTS WITH THE PROPER CONFIGURATION AND LINEARIZATION TECHNIQUES" referencing "Feed Forward Linear Amplifiers" (op. cit.) and "RF Power Amplifiers for Wireless Communications" (op. cit.) and So on and so on and so on (no deviance from commonplace design considerations that have been described for generations). 73's Richard Clark, KB7QHC |
Install a matching network that achieves a quasi-conjugate match between the network and the load. That's what I do. :-) -- 73, Cecil ====================== My dear Cecil, 99% of the contributors to this newsgroup, particularly the professionals, should make appointments to see a shrink. Problem? - the inabilty to grasp what is staring them in the face. It's a sad reflection on the present state of electrical engineering educational facilities in the Western world. Never mind, there's still hope, the Chinese, Vietamese, Hindu's, Indianesians, etc., will help us to sort out such trivial matters as vswr. The problem of sharing energy resources will take a little longer. I have just opened a bottle of Chilean, Isla Negra, Cabernet Sauvignon. I can't read what else it says on the label. But we musn't neglect our good (South) American near-neighbours and friends. I am listening to the BBC. The World's finest educational facility although it sounds more like the VOA than the VOA. It seems that a very large proportion of the Virginian forefathers were of the criminal classes, convicts, conveyed in chains, who shared there lives on arrival with negro slaves. Life expectancy in Baltimore and Maryland was about 7 years. Between 50,000 and 100,000 convicts were exported to the Land of the Free. They were present at the Alamo and assisted at many other places to rid the land of the original inhabitants. Is this proudly recorded in your children's history books? Shot any rattlers lately? From a sincere European friend of all USA citizens, descendents of convicts, SWR worshippers, conjugal-match adherents, voters even for Bush, or otherwise. Reply not needed. ---- Punchinello, G4FGQ |
On Mon, 6 Sep 2004 20:24:44 +0000 (UTC), "Reg Edwards"
wrote: make appointments to see a shrink Good advice. Does yours offer refunds? I doubt if there are any measureables that Lord Kelvinator could use to derive a cost/benefit ratio - hence your shrink's depostis are secure. Stick with the wine, at least you know where your money is going, and it keeps you out of the mud. ;-) 73's Richard Clark, KB7QHC |
On Mon, 6 Sep 2004 20:24:44 +0000 (UTC), "Reg Edwards"
wrote: Install a matching network that achieves a quasi-conjugate match between the network and the load. That's what I do. :-) -- 73, Cecil ====================== My dear Cecil, 99% of the contributors to this newsgroup, particularly the professionals, should make appointments to see a shrink. Problem? - the inabilty to grasp what is staring them in the face. It's a sad reflection on the present state of electrical engineering educational facilities in the Western world. Never mind, there's still hope, the Chinese, Vietamese, Hindu's, Indianesians, etc., will help us to sort out such trivial matters as vswr. The problem of sharing energy resources will take a little longer. I have just opened a bottle of Chilean, Isla Negra, Cabernet Sauvignon. I can't read what else it says on the label. But we musn't neglect our good (South) American near-neighbours and friends. I am listening to the BBC. The World's finest educational facility although it sounds more like the VOA than the VOA. It seems that a very large proportion of the Virginian forefathers were of the criminal classes, convicts, conveyed in chains, who shared there lives on arrival with negro slaves. Life expectancy in Baltimore and Maryland was about 7 years. Between 50,000 and 100,000 convicts were exported to the Land of the Free. They were present at the Alamo and assisted at many other places to rid the land of the original inhabitants. Is this proudly recorded in your children's history books? Shot any rattlers lately? From a sincere European friend of all USA citizens, descendents of convicts, SWR worshippers, conjugal-match adherents, voters even for Bush, or otherwise. Reply not needed. ---- Punchinello, G4FGQ Hello All, Reg's post above just gave away his cover as an undersea transmission-line engineer that renders his failure to comprehend SWR, conjugate match, oops, I mean conjugal match, completely comprehensible. I know his relevation was totally inadvertant, but it's evident to this SWR worshipper that he's really a situp comedian empowered with an overdose of, what did he call it, Kavurnay Sawvignun? He admitted he couldn't read what was printed on the bottle. So let's all take pity on this sensitive guy who's beyond his depth in trying to fathom our attempts to bring him up to speed on the vocabulary required for speaking intelligently on the vital engineering issues we discuss on this important media of understanding. God bless the Cween. Walt |
On Mon, 06 Sep 2004 12:57:50 -0700, Wes Stewart wrote:
On Mon, 06 Sep 2004 18:41:37 GMT, Walter Maxwell wrote: [snip] |Thanks for the compliment, Reg, that you prefer to take my word for it. However, |the reason we include the manufacturer is not as a gratuitutous advert, but to |distinguish between the Cadillacs (Hewlett-Packard and General Radio, among a |few others) and the non-descripts. The Cadillacs are professional, precision |instruments, which, when used by knowledgeable people, provide data that can be |relied upon. | |Without knowledge of the quality of the measuring device the reader is |justifiably suspicious of the data. Careful Walt. Reg is an Englishman, he doesn't know what at Cadillac is, other than an American automobile, which makes it suspect. You should use Jaguar for comparison. Uh oh, better not, that is an American company (Ford). Alright, how about Aston Martin. Darn, another Ford. I've got it; Rolls-Royce! Nope, that's a German car (BMW). Okay maybe a Bentley. Nooo. That's a Volkswagon. Surely a Land Rover. Not again! Another Ford. You're right. HP and GR were the Cadillacs of the industry. [g] Man, Wes, I sure ran of the road and totalled the Caddie on this one, didn't I? However, what happened to the Rolls-Royce? Did the Queen boot it out? As I recall it from my pre-teen days, it was definitely a Brit. And how did it manage to land in Deutchland? Or did Neville Chamberlin manipulate this one too? Walt |
Walter, W2DU wrote:
"The internal resistance in Class B and C amps has two parts, 1) the cathode-to-plate resistance, which is dissipative, and 2) the non-dissipative resistance established by the V/I ratio within the pi-network tank circuit -- a high resistance at the input and a low resistance at the output." It`s true that a parallel resonant circuit constructed of ideal inductance and capacitance has high (infinite) impedance and no loss. The configuration of the high impedance in series with the load limits output. But, we use imperfect components and we seek a limiting impedance equat to the 50-ohm load, not an infinite impedance. My take on the non-dissipative impedance is that it comes from the switched-off time of the Class B and C amps. During this time in each cycle, no current flows through the amp to cause loss. Likewise, there is no current from the amp (actually it is a switch operating on and off at a radio frequency) to the load or tank circuit. The tank circuit cleans up the pulse mess, filling gaps in the RF cycle. Best regards, Richard Harrison, KB5WZI |
Thanks Stew for your valient attempt to clarify the meaning of Quality in the electrical measuring instrument field in terms of the motor industry. Unfortunately the motor industry, as is everything else, is now in the hands of the International Corporations and is all mixed up. We are left only with the remains of the confusion with the quality description "Rolls Royce" which all nationalities understand. It remains for the same reason that the English language remains. Rolls Royce appeared at the end of the British era of engineering supremacy which began with the Bimingham Wire Gauge around the time of the French revolution and continued through the beautiful Boulton and Watt reciprocating, condensing steam engines which ruled the Earth for 80 years, as did Britannia's well-engineered battleships and 16-inch, 18-inch guns. Our German friends took over at the battle of Jutland and the Bismark incident. But the optical qualities of Zeiss rangefinders probably had something to do with it. But to avoid an international incident, it should be stated the ordinary engineering educated Englishman quite understands the meaning of "Cadillac" although he may not have the foggiest idea of where the name came from. Was it named after a red-indian tribe such as Cincinatti or Detroit? By the way, I sometimes think that mention or reference to a particular measuring instrument or the name of a prominent author implies a lack of self-confidence and conviction in what one is stating. As for me, I rarely make such mentions if only to avoid the danger of mis-quoting. The responsibity is then entirely mine. Although I may jokingly profess ignorance of American electrical measuring instruments, for several years I was the Government-approved Head of Laboratory of a measurement standards laboratory of second echelon to the British National Physical Laboratory. I was familiar with the excellent qualities of HP, GR, Fluke and similar instruments. I played an original part in the conversion of the assessment of National worst-case measurement uncertainties to statistical uncertainty assssment. But I don't brag about it. ---- Reg, G4FGQ ====================================== Thanks for the compliment, Reg, that you prefer to take my word for it. However, |the reason we include the manufacturer is not as a gratuitutous advert, but to |distinguish between the Cadillacs (Hewlett-Packard and General Radio, among a |few others) and the non-descripts. The Cadillacs are professional, precision |instruments, which, when used by knowledgeable people, provide data that can be |relied upon. | |Without knowledge of the quality of the measuring device the reader is |justifiably suspicious of the data. Careful Walt. Reg is an Englishman, he doesn't know what at Cadillac is, other than an American automobile, which makes it suspect. You should use Jaguar for comparison. Uh oh, better not, that is an American company (Ford). Alright, how about Aston Martin. Darn, another Ford. I've got it; Rolls-Royce! Nope, that's a German car (BMW). Okay maybe a Bentley. Nooo. That's a Volkswagon. Surely a Land Rover. Not again! Another Ford. You're right. HP and GR were the Cadillacs of the industry. [g] |
|
For a story about one of the things that made Cadillac "The Cadillac" of
automobiles, see http://www.uh.edu/engines/epi133.htm. Caddilac, incidentally, was named after Le Sieur Antoine de la Mothe Cadillac, the Frenchman who in 1701 built a stockade, trading post, and settlement called Ville d’Etroit, now known as Detroit. See http://www.cadillacforums.com/cadillac-history.html. Roy Lewallen, W7EL Reg Edwards wrote: . . . But to avoid an international incident, it should be stated the ordinary engineering educated Englishman quite understands the meaning of "Cadillac" although he may not have the foggiest idea of where the name came from. Was it named after a red-indian tribe such as Cincinatti or Detroit? . . . |
Wes wrote:
"I`ve got it: Rolls-Royce! Nope, that`s a German car (BMW)." Who makes the Rolls-Royce jet engines now? Our company`s first jet airtcraft was a Vickers Viscount prop-jet. We were in a long cue waiting for one when a wire from Vickers came saying Cubana Airlines had defaulted on an executive outfitted Viscount for Fidel Castro. Did anyone in the cue want the aircraft? Our chief pilot asked the dhairman if he could buy it? The answer was yes. It was already outfitted almost as we would have done anyway except our labeling would have been in English instead of Spanish. I remember landing in Antafagasto Chile right after we got the Viscount. The Shell Oil tank truck charged out and the operator asked our pilot, Charlie Walling, which grade of kerosene he wanted, JP-1,2,3,or 4, etc. Charlie replied he would have to consult the owners manual, a really big tome. The book said any grade is fine for the Rolls-Royce turbines. Charlie told the Shell guy to fill it with whatever grade he was long on. Sure enough, the engines lit right off and ran fine. Most remarkable was after a flight from Houston, all the engines only required about a teacup of oil. Our piston engined aircraft would have consumed gallons of oil on the same flight. Besty regards, Richard Harrison, KB5WZI |
Wes wrote:
"I`ve got it: Rolls-Royce! Nope, that`s a German car (BMW)." Germans respect British motors. The Messerschmitt Bf 109 resulted from a competition spurred by a request for proposal to build a new German fighter aircraft. The Messerschmitt was one of 3 designs from competing manufacturers who built prototypes for the competition. All 3 featured British Merlin engines! The production Bf 109 had a 1475 hp Daimler-Benz engine, but a Merlin powered it to victory in competition. Hermann Goering declared in Berlin, "If the enemy bombs this place my name is Mud." Later, as he arrived in a bomb shelter, he said,"Let me introduce myself. My name is Mud." A famous German fighter leaded once asked his commander for a squadron of Spitfires! Best regards, Richard Harrison, KB5WZI |
In article ,
"Reg Edwards" wrote: But to avoid an international incident, it should be stated the ordinary engineering educated Englishman quite understands the meaning of "Cadillac" although he may not have the foggiest idea of where the name came from. Was it named after a red-indian tribe such as Cincinatti or Detroit? Debunking mode ON Cincinnati, Ohio (not Cincinatti) was named not after what we in Canada call a First Nation but instead after the Society of the Cincinnati, an organization formed after the American War of Revolution (1776 and all that). The organization was composed of former American Army officers. The Society of Cincinnati, in turn, took its name from Lucius (Titus) Quinctius Cincinnatus, a farmer and former consul who was asked to leave his fields to become dictator to defend Rome against outsiders, in 458 BC. Under his command Rome's enemies were defeated, and 16 days later he returned to his farm. Cadillac, Michigan was named after Antoine Laumet de La Mothe Cadillac, a Frenchman established a settlement near what is now Detroit, Michigan, in 1701, and the automobile was named after either the city or the French settler. Debunking mode OFF David (1) born in Cincinnati, Ohio in 1935 (2) licenced as W8EZE in that city in 1949 (3) learned about Cincinnatus in grade school (4) wishes that certain US politicians would just return to their ranches where they could only harm rattlesnakes and cactus plants -- David Ryeburn To send e-mail, use "ca" instead of "caz". |
Roy Lewallen wrote:
"Cadillac, incidentally, was named after Le Sieur Antoine de la Mothe Cadillac, the Frenchman who in 1701 built a stockade, trading post and settlement called Ville d`Etroit now called Detroit." Something the "Engines of Our Ingenuity" story doesn`t tell us is that Cadillac was Henry Ford`s company which he sold to what was to become General Motors Best regards, Richard Harrison, KB5WZI |
Richard Clark wrote:
"This may displace WHERE the dissipation occurs, but it does not render reflected power an inert concept." No it doesn`t, but it doesn`t require its acceptance back in the transmitter either. I`ll repost my earlier posting as near as I can reconstruct it. It seems to be lost in cyberspace. Walter Maxwell, W2DU wrote: "Consequently, the reflected power reaching the network output is not absorbed, but instead adds to the power delivered by the generator." My explanation for the above, which is my observation too, is that an energy wave experiences a phase reversal between the volts and amps which it will generate after reflection. That fact makes Bird`s directional coupler in its wattmeter work. The transmitter`s output isn`t receptive and won`t absorb a wave that produces out-of-phase volts and amps, so the reflected wave is re-reflected from the transmitter, placing its amps and volts back in-phase. The newly minted RF and the twice reflected RF are similar, both having their volts and amps in-phase. So, the similar RF constituents merge to have a go at the reflection point. Best regards, Richard Harrison, KB5WZI |
On Mon, 6 Sep 2004 23:15:24 -0500, (Richard
Harrison) wrote: The newly minted RF and the twice reflected RF are similar, both having their volts and amps in-phase. Hi Richard, In a reality of 359 other possible phase angles, how does a transmitter happen to always be "in-phase" to any reflection? 73's Richard Clark, KB7QHC |
Bob Nielsen wrote:
On Mon, 06 Sep 2004 22:26:16 GMT, Walter Maxwell wrote: However, what happened to the Rolls-Royce? Did the Queen boot it out? As I recall it from my pre-teen days, it was definitely a Brit. And how did it manage to land in Deutchland? Or did Neville Chamberlin manipulate this one too? Still made in Britain, but owned by BMW, who also make the recent incarnation of Minis. The original MGs were built right here in Abingdon-on-Thames, and the big factory where the Minis are made is just up the road in Oxford. Lots of local people either are or have worked in the car industry... and some of them are also hams. Even when R-R Motors was an independent company, it used part of the big Oxford factory. That much larger company eventually bought R-R, but in turn has done deals in which first Honda and then BMW provided transfusions of new technology in return for a large share of the company itself. However, the company still makes its own cars under the name Austin Rover. R-R Motors has always been a separate operation, with very different ways of doing things. For example, all the stories you've heard about countless coats of paint, each one hand-applied and hand-rubbed, are true. The comforting thing is that down at the other end of the factory, cars for the rest of us are being stamped out with modern high-tech, high-bake paint jobs that will wear far better. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Richard Harrison wrote:
Who makes the Rolls-Royce jet engines now? Rolls-Royce do. The aero engine operation separated from the original car building operation in the 1970s. When the two companies split, they were smart enough to let both keep the hugely valuable brand name - unlike Hewlett-Packard. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
"Ian White, G3SEK" wrote in message ... Richard Harrison wrote: Who makes the Rolls-Royce jet engines now? Rolls-Royce do. The aero engine operation separated from the original car building operation in the 1970s. When the two companies split, they were smart enough to let both keep the hugely valuable brand name - unlike Hewlett-Packard. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek Ummm, what part of hijack & pillage are you uncomfortable about? Ed wb6wsn |
Ed Price wrote:
Who makes the Rolls-Royce jet engines now? Rolls-Royce do. The aero engine operation separated from the original car building operation in the 1970s. When the two companies split, they were smart enough to let both keep the hugely valuable brand name - unlike Hewlett-Packard. Ummm, what part of hijack & pillage are you uncomfortable about? No problem with the old "High-Priced" brand name at all - it's the other one... -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) http://www.ifwtech.co.uk/g3sek |
Richard Harrison wrote:
The newly minted RF and the twice reflected RF are similar, both having their volts and amps in-phase. So, the similar RF constituents merge to have a go at the reflection point. Wonder why we have protection circuitry in transmitters? The superposed forward voltage and reflected voltage can damage an unprotected transmitter. The superposed forward current and reflected current can cause over heating in an unprotected transmitter. The transmitter sees whatever impedance it sees and that impedance can be highly reactive. The superposed voltage can be high or low. The superposed current can be high or low. The phase between the superposed voltage and superposed current can have lots of values. Just a for instance - assume the transmitter is putting out 70.7v in phase with 1.4a at zero deg. The arriving reflected wave is 50v at 90 deg and 1.0a at -90 deg. The load seen by the transmitter is 86.6v at 35 deg and 1.72a at -35 deg. Over voltage and over current exist at the transmitter output. The forward power is 100w and the reflected power is 50w. The net power being delivered to the reactive "load" seen by the transmitter is 86.6*1.72*cos(70.4) = 50w. The math model is trying to dictate reality. It is supposed to be exactly the opposite. There is no magic barrier that automatically rejects reflected energy from a transmitter. Reflected energy arriving at the transmitter can drastically alter the impedance away from the designed-for load impedance. The transmitter sees one of the transformed impedances that exists on the SWR circle. Note that the problem disappears in a matched system where reflected energy is not allowed to reach the transmitter. -- 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:
"In a reality of 359 other possible phase angles, how does a transmitter happen to always be in-phase to any reflection?" Connect any generator to any resistor, and current in the resistor is in-phase with the applied voltage. The Zo of the common transmission line is a reasonably good resistance. At radio frequencies, Zo is independent of frequency. The current in the incident wave is always in-phase with the voltage applied to a transmission line. The current in the reflected wave is always 180-degrees out-of-phase with the reflected voltage. It makes no difference which was inverted by reflection, the volts or tha amps, one, and only one, of them was flipped upside down. The transmission line can and does handle the reflected wave. Standing waves display interference between incident and reflected waves whiich ideally have in-phase and out-of-phase constituents. The fact that the Bird wattmeter works is evidence that the theory is correct at least until a better theory replaces existing theory. Best regards, Richard Harrison, KB5WZI |
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Cecil, W5DXP wrote:
"The superposed forward voltage and reflected voltage can damage an unprotected transmitter." To do so, they would be in-phase and not out-of-phase. Entirely possible if the transmission line is the right length. If the reflected volts are in the same phase as the newly munted volts, which are larger? With a reflection coefficient of 1, and a lossless line, the open-circuit value of transmitter volts would face some lower value of line volts on opposite ends of the internal impedance of the transmitter. Which way does the current flow? Theory is that it flows from the higher to the lower. That is, from the transmitter to the line. Best regards, Richard Harrison, KB5WZI |
Richard Clark wrote:
In a world of mismatches, how does it happen that the transmitter always sees an in-phase, resistive load?" It doesn`t. You can put a capacitor directly across its output terminals, and the transmitter will energize the capacitor. But, a transmission line is not a capacitor unless it is a short open circuit, or the equivalent. A transmission line is a distributed network of inductance and capacitance. This network transfers emergy in bucket brigade fashion. The "brigade" presents a resistive impedance to both the incident wave and to the reflected wave. Zo is an enforcer. Best regards, Richard Harrison, KB5WZI |
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