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Looking for information on VHF impedance measurement
In a recent thread on VHF impedance measurement, it was indicated that
VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
This impedance meter is based on SM6MOM's winning entry in the RF Design
Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
This impedance meter is based on SM6MOM's winning entry in the RF Design
Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
Thanks Richard
ManOMan - This stuff gets complex. I dont have a VHF sweep signal generator. I suspect graphic display requires a sweep signal generator. I once owned a 1947 Proceedings of The IRE. I tossed all my "magazines" long ago. I wish I could have known. I'd have saved that one (thats a funny) The instructions I read for the single frequency method with the 1/8th lambda coaxs, indicates that the meter reads 80+j12 when the terminal is loaded with 60+j50. Thats probably OK, but it would sure confuse me. But, since I beleive the guy who wrote this article is smarter than I am, I would just like to get some of my confusion cleared up. In the mean time, I'll go try to dig up "Samuels's" article. Who knows, maybe I'll learn something. Jerry "Rick Karlquist N6RK" wrote in message news:st5Fc.11168$wY5.9000@attbi_s54... This impedance meter is based on SM6MOM's winning entry in the RF Design Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
Thanks Richard
ManOMan - This stuff gets complex. I dont have a VHF sweep signal generator. I suspect graphic display requires a sweep signal generator. I once owned a 1947 Proceedings of The IRE. I tossed all my "magazines" long ago. I wish I could have known. I'd have saved that one (thats a funny) The instructions I read for the single frequency method with the 1/8th lambda coaxs, indicates that the meter reads 80+j12 when the terminal is loaded with 60+j50. Thats probably OK, but it would sure confuse me. But, since I beleive the guy who wrote this article is smarter than I am, I would just like to get some of my confusion cleared up. In the mean time, I'll go try to dig up "Samuels's" article. Who knows, maybe I'll learn something. Jerry "Rick Karlquist N6RK" wrote in message news:st5Fc.11168$wY5.9000@attbi_s54... This impedance meter is based on SM6MOM's winning entry in the RF Design Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
This method is a narrow band method. You could sweep over
a narrowband (like an amateur band). What the 1947 article did was use diode detectors in the square law region connected to an X-Y scope. The display on the scope is a Smith chart view. Without a scope, you would use a voltmeter and plot on a paper Smith chart. I have actually built this and it works, although it is only as accurate as the squarelaw detectors. You could also use linear detectors, and use a calculator to square the number then plot on a paper Smith chart. I have emailed you a copy of the 1947 paper. (finally remembered where I stored it). Rick N6RK "Jerry Martes" wrote in message ... Thanks Richard ManOMan - This stuff gets complex. I dont have a VHF sweep signal generator. I suspect graphic display requires a sweep signal generator. I once owned a 1947 Proceedings of The IRE. I tossed all my "magazines" long ago. I wish I could have known. I'd have saved that one (thats a funny) The instructions I read for the single frequency method with the 1/8th lambda coaxs, indicates that the meter reads 80+j12 when the terminal is loaded with 60+j50. Thats probably OK, but it would sure confuse me. But, since I beleive the guy who wrote this article is smarter than I am, I would just like to get some of my confusion cleared up. In the mean time, I'll go try to dig up "Samuels's" article. Who knows, maybe I'll learn something. Jerry "Rick Karlquist N6RK" wrote in message news:st5Fc.11168$wY5.9000@attbi_s54... This impedance meter is based on SM6MOM's winning entry in the RF Design Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
This method is a narrow band method. You could sweep over
a narrowband (like an amateur band). What the 1947 article did was use diode detectors in the square law region connected to an X-Y scope. The display on the scope is a Smith chart view. Without a scope, you would use a voltmeter and plot on a paper Smith chart. I have actually built this and it works, although it is only as accurate as the squarelaw detectors. You could also use linear detectors, and use a calculator to square the number then plot on a paper Smith chart. I have emailed you a copy of the 1947 paper. (finally remembered where I stored it). Rick N6RK "Jerry Martes" wrote in message ... Thanks Richard ManOMan - This stuff gets complex. I dont have a VHF sweep signal generator. I suspect graphic display requires a sweep signal generator. I once owned a 1947 Proceedings of The IRE. I tossed all my "magazines" long ago. I wish I could have known. I'd have saved that one (thats a funny) The instructions I read for the single frequency method with the 1/8th lambda coaxs, indicates that the meter reads 80+j12 when the terminal is loaded with 60+j50. Thats probably OK, but it would sure confuse me. But, since I beleive the guy who wrote this article is smarter than I am, I would just like to get some of my confusion cleared up. In the mean time, I'll go try to dig up "Samuels's" article. Who knows, maybe I'll learn something. Jerry "Rick Karlquist N6RK" wrote in message news:st5Fc.11168$wY5.9000@attbi_s54... This impedance meter is based on SM6MOM's winning entry in the RF Design Magazine contest in 1986. As I pointed out to the then editor of the magazine, the exact same impedance meter was described in the Proceedings of the IRE in 1947. You might want to read the article by the original inventor (I believe his name was Samuels and the title is something like "A Oscillographic Method of Impedance Measurement".) Rick N6RK "Jerry Martes" wrote in message ... In a recent thread on VHF impedance measurement, it was indicated that VK2ZAB had instructions for building an impedance meter. I have acquired all the parts needed for constructing a meter described in ZABs article. But, I am confused about how to operate it when/if the meter gets finished. I'd sure like to corespond with someone who has built and/or used one of these meters. Jerry |
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