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N2PK Network Analyser?
Is anyone building or thinking about building the above very interesting
project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr |
Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Hi Dan, great project eh? Superb results! Measuring things I never could before even with the Boonton 250. W4ZCB |
Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Hi Dan, great project eh? Superb results! Measuring things I never could before even with the Boonton 250. W4ZCB |
They're all spoken for, thanks.
dr Dan Rae wrote: Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr |
They're all spoken for, thanks.
dr Dan Rae wrote: Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr |
In article et, rae4
@ix.netcom.com says... Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr I may build one to play with it. Paul's documentation is awesome -- I can well imagine how much work he put into it. At a glance, though, there are a couple of things I would have (and may still) do differently if/when I get around to building a VNA: 1) I don't know that I'd use DDS synthesizers for an application like this. There's no need for serious close-in spectral purity, but you'd certainly like to have a higher frequency-coverate limit. Also, to achieve truly-meaningful measurements with an untuned receiver section, suppression of harmonic content in the test signal might be more critical than the existing design allows. (Imagine trying to characterize a high-pass filter with an untuned receiver and DDS harmonics coming through at -30 dBc.) The latter may not be a concern if the AD9851's harmonics (and those generated in any subsequent output buffer stage) are very low in amplitude. 2) Hand-building couplers and bridges doesn't make much sense when surplus HP8505-era test sets good to 1 GHz+ are as cheap as they are. If I were only concerned with HF, though, Paul's approach looks fine. 3) There's no excuse for not releasing the source code to the software, IMHO. A proprietary closed-source DOS app doesn't exactly lend itself to customization and improvement. In fact, we'll be lucky if this code even runs on the next generation of Windows. I'd urge Paul to reconsider his software strategy (assuming I'm not mistaken about it being closed-source in the first place). Pretty darned cool project, all in all. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
In article et, rae4
@ix.netcom.com says... Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr I may build one to play with it. Paul's documentation is awesome -- I can well imagine how much work he put into it. At a glance, though, there are a couple of things I would have (and may still) do differently if/when I get around to building a VNA: 1) I don't know that I'd use DDS synthesizers for an application like this. There's no need for serious close-in spectral purity, but you'd certainly like to have a higher frequency-coverate limit. Also, to achieve truly-meaningful measurements with an untuned receiver section, suppression of harmonic content in the test signal might be more critical than the existing design allows. (Imagine trying to characterize a high-pass filter with an untuned receiver and DDS harmonics coming through at -30 dBc.) The latter may not be a concern if the AD9851's harmonics (and those generated in any subsequent output buffer stage) are very low in amplitude. 2) Hand-building couplers and bridges doesn't make much sense when surplus HP8505-era test sets good to 1 GHz+ are as cheap as they are. If I were only concerned with HF, though, Paul's approach looks fine. 3) There's no excuse for not releasing the source code to the software, IMHO. A proprietary closed-source DOS app doesn't exactly lend itself to customization and improvement. In fact, we'll be lucky if this code even runs on the next generation of Windows. I'd urge Paul to reconsider his software strategy (assuming I'm not mistaken about it being closed-source in the first place). Pretty darned cool project, all in all. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
Can someone please tell me thw specific model numbers of the HP 8505 era
test sets that have directional couplers, etc that are good for HF. tnx hank wd5jfr "John Miles" wrote in message ... In article et, rae4 @ix.netcom.com says... Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr I may build one to play with it. Paul's documentation is awesome -- I can well imagine how much work he put into it. At a glance, though, there are a couple of things I would have (and may still) do differently if/when I get around to building a VNA: 1) I don't know that I'd use DDS synthesizers for an application like this. There's no need for serious close-in spectral purity, but you'd certainly like to have a higher frequency-coverate limit. Also, to achieve truly-meaningful measurements with an untuned receiver section, suppression of harmonic content in the test signal might be more critical than the existing design allows. (Imagine trying to characterize a high-pass filter with an untuned receiver and DDS harmonics coming through at -30 dBc.) The latter may not be a concern if the AD9851's harmonics (and those generated in any subsequent output buffer stage) are very low in amplitude. 2) Hand-building couplers and bridges doesn't make much sense when surplus HP8505-era test sets good to 1 GHz+ are as cheap as they are. If I were only concerned with HF, though, Paul's approach looks fine. 3) There's no excuse for not releasing the source code to the software, IMHO. A proprietary closed-source DOS app doesn't exactly lend itself to customization and improvement. In fact, we'll be lucky if this code even runs on the next generation of Windows. I'd urge Paul to reconsider his software strategy (assuming I'm not mistaken about it being closed-source in the first place). Pretty darned cool project, all in all. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
Can someone please tell me thw specific model numbers of the HP 8505 era
test sets that have directional couplers, etc that are good for HF. tnx hank wd5jfr "John Miles" wrote in message ... In article et, rae4 @ix.netcom.com says... Is anyone building or thinking about building the above very interesting project? http://users.adelphia.net/~n2pk/index.html If so, I have two printed circuit boards going spare at cost (about $22).... Dan ac6ao g3ncr I may build one to play with it. Paul's documentation is awesome -- I can well imagine how much work he put into it. At a glance, though, there are a couple of things I would have (and may still) do differently if/when I get around to building a VNA: 1) I don't know that I'd use DDS synthesizers for an application like this. There's no need for serious close-in spectral purity, but you'd certainly like to have a higher frequency-coverate limit. Also, to achieve truly-meaningful measurements with an untuned receiver section, suppression of harmonic content in the test signal might be more critical than the existing design allows. (Imagine trying to characterize a high-pass filter with an untuned receiver and DDS harmonics coming through at -30 dBc.) The latter may not be a concern if the AD9851's harmonics (and those generated in any subsequent output buffer stage) are very low in amplitude. 2) Hand-building couplers and bridges doesn't make much sense when surplus HP8505-era test sets good to 1 GHz+ are as cheap as they are. If I were only concerned with HF, though, Paul's approach looks fine. 3) There's no excuse for not releasing the source code to the software, IMHO. A proprietary closed-source DOS app doesn't exactly lend itself to customization and improvement. In fact, we'll be lucky if this code even runs on the next generation of Windows. I'd urge Paul to reconsider his software strategy (assuming I'm not mistaken about it being closed-source in the first place). Pretty darned cool project, all in all. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
In article ,
says... Can someone please tell me thw specific model numbers of the HP 8505 era test sets that have directional couplers, etc that are good for HF. HP 8503A is the 50-ohm S-parameter test set, good for ~40 dB directivity from near DC to 1 GHz. HP 8502A is the 50-ohm transmission-reflection test set, with a similar frequency range. The 'B' suffix refers to 75-ohm versions of these units. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
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