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Another HB VNA - opinions, please...
In article ,
says... Am I reading the block diag correctly-- in that the contest winner does not measure return parameters (S11 or S22) , but only through (S21, S12) the DUT? Davide's does return measurements. That was my impression. You'd have to use an external directional coupler to do reflectance measurements. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
Davide,
I don't think your design can resolve the sign of the phase angle, can it?? Joe W3JDR Steve Nosko wrote in message ... "iw3hev, Davide" wrote in message om... Paul Burridge wrote in message . .. Hi guys, Just come across this design for a self-build VNA and wondered what you thought of the spec: http://www.geocities.com/robert_laco...us_designs.htm Hello Paul, I have a similar type under testing but limited working frequency range 1.8-60 Mhz at www.qsl.net/iw3hev. The performances are not comparable to the VNA from N2PK but is good for antenna testing. Regards iw3hev Davide Am I reading the block diag correctly-- in that the contest winner does not measure return parameters (S11 or S22) , but only through (S21, S12) the DUT? Davide's does return measurements. -- Steve N, K,9;d, c. i My email has no u's. |
"Steve Nosko" wrote in message ...
"iw3hev, Davide" wrote in message om... Paul Burridge wrote in message . .. Hi guys, Just come across this design for a self-build VNA and wondered what you thought of the spec: http://www.geocities.com/robert_laco...us_designs.htm Hello Paul, I have a similar type under testing but limited working frequency range 1.8-60 Mhz at www.qsl.net/iw3hev. The performances are not comparable to the VNA from N2PK but is good for antenna testing. Regards iw3hev Davide Am I reading the block diag correctly-- in that the contest winner does not measure return parameters (S11 or S22) , but only through (S21, S12) the DUT? Davide's does return measurements. Steve, The unit performs reflection measurements using the internal directional coupler, the dynamic range is maximum 30 dB. For transmission measurements is necessary to add a second connector and a switch. By the switch we can change the type of the measurement from reflection to transmission. The switch will change the signals path of AD8302 inputs, for transmission measurement the directional coupler will became a power splitter (-15 dB to the first AD8302 input and the rest to the actual BNC connector-TX). The reflection port of the directional coupler will be terminated to 50 ohm only, meanwhile the second AD8302 input will be connected connect to the extra connector (RX). The software for transmission measurements is not yet ready but I believe shortly I can post. iw3hev, Davide |
Joe,
yes the sign of the reactance is not given but looking the X curve is easily understandable. Iw3hev, Davide "Joe Rocci" wrote in message news:IVwSc.9259$dG.4506@trndny02... Davide, I don't think your design can resolve the sign of the phase angle, can it?? Joe W3JDR Steve Nosko wrote in message ... "iw3hev, Davide" wrote in message om... Paul Burridge wrote in message . .. Hi guys, Just come across this design for a self-build VNA and wondered what you thought of the spec: http://www.geocities.com/robert_laco...us_designs.htm Hello Paul, I have a similar type under testing but limited working frequency range 1.8-60 Mhz at www.qsl.net/iw3hev. The performances are not comparable to the VNA from N2PK but is good for antenna testing. Regards iw3hev Davide Am I reading the block diag correctly-- in that the contest winner does not measure return parameters (S11 or S22) , but only through (S21, S12) the DUT? Davide's does return measurements. -- Steve N, K,9;d, c. i My email has no u's. |
"iw3hev, Davide" wrote in message om... "Steve Nosko" wrote in message ... "iw3hev, Davide" wrote in message om... Paul Burridge wrote in message . .. Hi guys, Just come across this design for a self-build VNA and wondered what you thought of the spec: http://www.geocities.com/robert_laco...us_designs.htm Hello Paul, I have a similar type under testing but limited working frequency range 1.8-60 Mhz at www.qsl.net/iw3hev. The performances are not comparable to the VNA from N2PK but is good for antenna testing. Regards iw3hev Davide Am I reading the block diag correctly-- in that the contest winner does not measure return parameters (S11 or S22) , but only through (S21, S12) the DUT? Davide's does return measurements. Steve, The unit performs reflection measurements using the internal directional coupler, the dynamic range is maximum 30 dB. For transmission measurements is necessary to add a second connector and a switch. By the switch we can change the type of the measurement from reflection to transmission. The switch will change the signals path of AD8302 inputs, for transmission measurement the directional coupler will became a power splitter (-15 dB to the first AD8302 input and the rest to the actual BNC connector-TX). The reflection port of the directional coupler will be terminated to 50 ohm only, meanwhile the second AD8302 input will be connected connect to the extra connector (RX). The software for transmission measurements is not yet ready but I believe shortly I can post. iw3hev, Davide I am confused. Are you describing YOUR unit or the one first referred to.? I hadn't looked at your design, if it is on the web site. I was referring to the Robert Lacoste site. That block diagram has no dir coupler shown, just splitters, so it looks like a through measuring device only. Am I off base somewhere? -- Steve N, K,9;d, c. i My email has no u's. |
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