Home |
Search |
Today's Posts |
#141
![]() |
|||
|
|||
![]()
Art, KB9MZ.....XG wrote:
"The Yagi was invented by Japanese in the early 1920 where America embraced the invention and where Japan did not." Close but no cigar. Truth Squad time again. The 3rd edition of Kraus` "Antennas" has the Yagi-Uda Story beginning on page 246. It Says: "This led to the publication of a series of articles from March 1926 to July 1929) in the Journal of the Institute of Electrical Engineers of Japan titled "On the Wireless Beam of Short Electric Waves." (Uda-1)." Best regards, Richard Harrison, KB5WZI |
#142
![]() |
|||
|
|||
![]()
"art" wrote
The antenna from the University is resonant, tho less efficient than ideal. _________________ Reprise for Art: The efficiency of an antenna system in radiating the power available at the antenna end of the transmission line connected to its feedpoint does not depend on whether or not the radiator itself is naturally resonant. It depends on... 1) the ratio of the radiation resistance of the radiating sections of the antenna to the sum of that radiation resistance with all other r-f resistances in the antenna system. The pure radiation resistance of an antenna depends on the effective length//configuration of, and the r-f current distribution along the conductors exposed to space -- but not those of any matching devices used in the system design (wherever located). 2) the degree of impedance match existing between the antenna feedpoint and the source (normally, a transmission line, including any matching network there). The DLM uses matching components within the length of a short vertical radiator with the goals of canceling the high capacitive reactance of this electrically short radiator, and changing the current distribution along the radiator for an average value higher than provided by base loading. So for the same losses in the r-f ground system, the DLM could have somewhat better system radiation efficiency than a base-loaded monopole of the same physical height. But good system efficiency would still be heavily dependent on the quality of the r-f ground used with it (just as in a "standard" monopole). This is not a revolutionary concept, as mid- and top-loading techniques have been used with vertical monopoles for many decades. RF |
#143
![]() |
|||
|
|||
![]()
Art wrote:
"I suppose ham radio reflects the veterans of WW2 there many of those who were doers are gradually dying off leaving former CBers in the majority." I qualify for all of the above, WW-2 overseas veteran, radio amateur, CBer, but I`m not dead yet. I also had a 1st class phone license and an E.E. degree, among others. Best regards, Richard Harrison, KB5WZI1 |
#144
![]() |
|||
|
|||
![]()
Art wrote:
"Now I have a mantra that if it is "resonant and in a state of equilibriun" it is what I call a Gaussian antenna." Yes, and the question still remains, are the lyrics sung because they are too silly to be repeated without the music? Best regards, Richard Harrison. KB5WZI |
#145
![]() |
|||
|
|||
![]()
On 4 Jul, 08:07, (Richard Harrison) wrote:
Art, KB9MZ.....XG wrote: "The Yagi was invented by Japanese in the early 1920 where America embraced the invention and where Japan did not." Close but no cigar. Truth Squad time again. The 3rd edition of Kraus` "Antennas" has the Yagi-Uda Story beginning on page 246. It Says: "This led to the publication of a series of articles from March 1926 to July 1929) in the Journal of the Institute of Electrical Engineers of Japan titled "On the Wireless Beam of Short Electric Waves." (Uda-1)." Best regards, Richard Harrison, KB5WZI The truth! Where is the lie? |
#146
![]() |
|||
|
|||
![]()
On 4 Jul, 08:14, "Richard Fry" wrote:
"art" wrote The antenna from the University is resonant, tho less efficient than ideal. _________________ Reprise for Art: The efficiency of an antenna system in radiating the power available at the antenna end of the transmission line connected to its feedpoint does not depend on whether or not the radiator itself is naturally resonant. It depends on... 1) the ratio of the radiation resistance of the radiating sections of the antenna to the sum of that radiation resistance with all other r-f resistances in the antenna system. The pure radiation resistance of an antenna depends on the effective length//configuration of, and the r-f current distribution along the conductors exposed to space -- but not those of any matching devices used in the system design (wherever located). 2) the degree of impedance match existing between the antenna feedpoint and the source (normally, a transmission line, including any matching network there). The DLM uses matching components within the length of a short vertical radiator with the goals of canceling the high capacitive reactance of this electrically short radiator, and changing the current distribution along the radiator for an average value higher than provided by base loading. So for the same losses in the r-f ground system, the DLM could have somewhat better system radiation efficiency than a base-loaded monopole of the same physical height. But good system efficiency would still be heavily dependent on the quality of the r-f ground used with it (just as in a "standard" monopole). This is not a revolutionary concept, as mid- and top-loading techniques have been used with vertical monopoles for many decades. RF The term " cancelling " is not correct tho people seem to be happy with it. In fact is it is not CANCELLING anything as it is actually adding to provide a state of equilibrium. Big difference Art |
#147
![]() |
|||
|
|||
![]()
Art wrote:
"Where is the lie?" The inventors were not without honor on their own land! Best regards, Richard Harrison, KB5WZI |
#148
![]() |
|||
|
|||
![]()
On 4 Jul, 10:11, (Richard Harrison) wrote:
Art wrote: "Where is the lie?" The inventors were not without honor on their own land! Best regards, Richard Harrison, KB5WZI Bull, They were ignored.Japan had not implimented the idea up till such time that one was captured from the Allies. Pretty much the same as with the inventor of the concept "Just in time" for Industry. Reverred in Japan and ignored in the U.S.until the Japanese "invasion." What I said is NOT A LIE. Unfortunately Kraus must have died thus preventing its addition to his book. Seems like you need to get a book that is up to date and relavent before you call me a LIAR. |
#149
![]() |
|||
|
|||
![]()
Art wrote:
"Bull. They were ignored. Japan had not implemented the idea up till such time that one was captured from the allies." Wikiipedia history confirms Art`s version of the Yagi`s story. I was wrong. I appologize. The Japanese paid little attention to their own invention. How did we get so lucky? Sorry for accusing Art of Yagi misinformation. Now, I think we are agreed that resonance is a nonreactive load. I don`t know what Art means by "equilibrium" in regard to the dynamic electrical characteristics of an antenna. We know that the same quantity can be added to both sides of an equation and just like a scale balance, no change in value occurs. Twenty questions should not be required to get an answer. Best regards, Richard Harrison, KB5WZI |
#150
![]() |
|||
|
|||
![]()
"art" wrote
The term " cancelling " is not correct tho people seem to be happy with it. In fact is it is not CANCELLING anything as it is actually adding to provide a state of equilibrium. Big difference. _____________ That's what you meant by equilibrium ! Kindly note that "equilibrium" (or resonance) does not need to be an attribute of the radiator itself, only a desirable attribute of the complete antenna system. RF |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|