It just occurred to me that one of these nano-VNA's would be the cat's meow for checking out attenuators and terms at swap meets. And, to some extent, filters, too, limited by the frequency coverage of the nano. Dana

Yep. From Tom Holmes, N8ZM > On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list <mvus-list@lists.febo.com> wrote: > > It just occurred to me that one of these nano-VNA's would > be the cat's meow for checking out attenuators and terms > at swap meets. And, to some extent, filters, too, limited > by the frequency coverage of the nano. > > Dana > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Tom, 30 years or so ago, I used to carry around an HP calculator (probably an HP41 or HP67) with a rather interesting program loaded. The idea is that you'd take an attenuator under test, hook an ohmmeter to one port, and measure the resistance looking into that port for both a short and an open at the other end. Enter the numbers into the calculator, then turn the attenuator around and do the measurements again, and enter that pair of numbers. Hit the "go" button, and the calculator would display the characteristic impedance at each port of the attenuator as well as the power attenuation. If the impedances at both ends were correct and the attenuation value was correct, then you could buy the attenuator with confidence that it had not been damaged. But the nano-VNA would be soooo much cooler! And faster, too. I wish I had had mine at MUD 2019 a couple of weeks ago- I would probably have spent more money on attenuators and perhaps some filters as well. There were a fair number of filters there, but I could not decode the part numbers to get the bandwidths, and the nano could have helped for the lower frequency filters. Dana On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < mvus-list@lists.febo.com> wrote: > Yep. > > From Tom Holmes, N8ZM > > > On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < > mvus-list@lists.febo.com> wrote: > > > > It just occurred to me that one of these nano-VNA's would > > be the cat's meow for checking out attenuators and terms > > at swap meets. And, to some extent, filters, too, limited > > by the frequency coverage of the nano. > > > > Dana > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Do you still have the program?  I could load it in my 41 emulator program on my Android phone! Daun Daun E. Yeagley II, N8ASB On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: > Tom, > > 30 years or so ago, I used to carry around an HP calculator (probably an > HP41 > or HP67) with a rather interesting program loaded. The idea is that you'd > take > an attenuator under test, hook an ohmmeter to one port, and measure the > resistance looking into that port for both a short and an open at the other > end. > Enter the numbers into the calculator, then turn the attenuator around and > do > the measurements again, and enter that pair of numbers. Hit the "go" > button, and the calculator would display the characteristic impedance at > each > port of the attenuator as well as the power attenuation. If the impedances > at > both ends were correct and the attenuation value was correct, then you could > buy the attenuator with confidence that it had not been damaged. > > But the nano-VNA would be soooo much cooler! And faster, too. I wish I > had had mine at MUD 2019 a couple of weeks ago- I would probably have > spent more money on attenuators and perhaps some filters as well. There > were a fair number of filters there, but I could not decode the part numbers > to get the bandwidths, and the nano could have helped for the lower > frequency > filters. > > Dana > > > On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < > mvus-list@lists.febo.com> wrote: > >> Yep. >> >> From Tom Holmes, N8ZM >> >>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < >> mvus-list@lists.febo.com> wrote: >>> It just occurred to me that one of these nano-VNA's would >>> be the cat's meow for checking out attenuators and terms >>> at swap meets. And, to some extent, filters, too, limited >>> by the frequency coverage of the nano. >>> >>> Dana >>> _______________________________________________ >>> mvus-list mailing list >>> mvus-list@lists.febo.com >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

This discussion started on a different list, so a number of those on that list missed this discussion. On Sun, Oct 20, 2019, 10:31 PM Daun Yeagley via mvus-list < mvus-list@lists.febo.com> wrote: > Do you still have the program? I could load it in my 41 emulator > program on my Android phone! > > Daun > Daun E. Yeagley II, N8ASB > On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: > > Tom, > > > > 30 years or so ago, I used to carry around an HP calculator (probably an > > HP41 > > or HP67) with a rather interesting program loaded. The idea is that > you'd > > take > > an attenuator under test, hook an ohmmeter to one port, and measure the > > resistance looking into that port for both a short and an open at the > other > > end. > > Enter the numbers into the calculator, then turn the attenuator around > and > > do > > the measurements again, and enter that pair of numbers. Hit the "go" > > button, and the calculator would display the characteristic impedance at > > each > > port of the attenuator as well as the power attenuation. If the > impedances > > at > > both ends were correct and the attenuation value was correct, then you > could > > buy the attenuator with confidence that it had not been damaged. > > > > But the nano-VNA would be soooo much cooler! And faster, too. I wish I > > had had mine at MUD 2019 a couple of weeks ago- I would probably have > > spent more money on attenuators and perhaps some filters as well. There > > were a fair number of filters there, but I could not decode the part > numbers > > to get the bandwidths, and the nano could have helped for the lower > > frequency > > filters. > > > > Dana > > > > > > On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < > > mvus-list@lists.febo.com> wrote: > > > >> Yep. > >> > >> From Tom Holmes, N8ZM > >> > >>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >>> It just occurred to me that one of these nano-VNA's would > >>> be the cat's meow for checking out attenuators and terms > >>> at swap meets. And, to some extent, filters, too, limited > >>> by the frequency coverage of the nano. > >>> > >>> Dana > >>> _______________________________________________ > >>> mvus-list mailing list > >>> mvus-list@lists.febo.com > >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Gads, no, Daun. That was more than 35 years ago! The impedance part is so simple that I remember it, however. The impedance of port 1, for example, is the geometric mean of the two resistance values obtained at port one as a result of shorting and opening port two, and vice versa. The atten value is more involved and I'd have to re-derive it (if I still remember how to do algebra). Dana On Sun, Oct 20, 2019 at 9:30 PM Daun Yeagley via mvus-list < mvus-list@lists.febo.com> wrote: > Do you still have the program? I could load it in my 41 emulator > program on my Android phone! > > Daun > Daun E. Yeagley II, N8ASB > On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: > > Tom, > > > > 30 years or so ago, I used to carry around an HP calculator (probably an > > HP41 > > or HP67) with a rather interesting program loaded. The idea is that > you'd > > take > > an attenuator under test, hook an ohmmeter to one port, and measure the > > resistance looking into that port for both a short and an open at the > other > > end. > > Enter the numbers into the calculator, then turn the attenuator around > and > > do > > the measurements again, and enter that pair of numbers. Hit the "go" > > button, and the calculator would display the characteristic impedance at > > each > > port of the attenuator as well as the power attenuation. If the > impedances > > at > > both ends were correct and the attenuation value was correct, then you > could > > buy the attenuator with confidence that it had not been damaged. > > > > But the nano-VNA would be soooo much cooler! And faster, too. I wish I > > had had mine at MUD 2019 a couple of weeks ago- I would probably have > > spent more money on attenuators and perhaps some filters as well. There > > were a fair number of filters there, but I could not decode the part > numbers > > to get the bandwidths, and the nano could have helped for the lower > > frequency > > filters. > > > > Dana > > > > > > On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < > > mvus-list@lists.febo.com> wrote: > > > >> Yep. > >> > >> From Tom Holmes, N8ZM > >> > >>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >>> It just occurred to me that one of these nano-VNA's would > >>> be the cat's meow for checking out attenuators and terms > >>> at swap meets. And, to some extent, filters, too, limited > >>> by the frequency coverage of the nano. > >>> > >>> Dana > >>> _______________________________________________ > >>> mvus-list mailing list > >>> mvus-list@lists.febo.com > >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Does it matter if it’s a tee or pi configuration? From Tom Holmes, N8ZM > On Oct 21, 2019, at 12:31 AM, Dana Whitlow via mvus-list <mvus-list@lists.febo.com> wrote: > > Gads, no, Daun. That was more than 35 years ago! > > The impedance part is so simple that I remember it, > however. The impedance of port 1, for example, is > the geometric mean of the two resistance values > obtained at port one as a result of shorting and opening > port two, and vice versa. The atten value is more > involved and I'd have to re-derive it (if I still remember > how to do algebra). > > Dana > > >> On Sun, Oct 20, 2019 at 9:30 PM Daun Yeagley via mvus-list < >> mvus-list@lists.febo.com> wrote: >> >> Do you still have the program? I could load it in my 41 emulator >> program on my Android phone! >> >> Daun >> Daun E. Yeagley II, N8ASB >>> On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: >>> Tom, >>> >>> 30 years or so ago, I used to carry around an HP calculator (probably an >>> HP41 >>> or HP67) with a rather interesting program loaded. The idea is that >> you'd >>> take >>> an attenuator under test, hook an ohmmeter to one port, and measure the >>> resistance looking into that port for both a short and an open at the >> other >>> end. >>> Enter the numbers into the calculator, then turn the attenuator around >> and >>> do >>> the measurements again, and enter that pair of numbers. Hit the "go" >>> button, and the calculator would display the characteristic impedance at >>> each >>> port of the attenuator as well as the power attenuation. If the >> impedances >>> at >>> both ends were correct and the attenuation value was correct, then you >> could >>> buy the attenuator with confidence that it had not been damaged. >>> >>> But the nano-VNA would be soooo much cooler! And faster, too. I wish I >>> had had mine at MUD 2019 a couple of weeks ago- I would probably have >>> spent more money on attenuators and perhaps some filters as well. There >>> were a fair number of filters there, but I could not decode the part >> numbers >>> to get the bandwidths, and the nano could have helped for the lower >>> frequency >>> filters. >>> >>> Dana >>> >>> >>> On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < >>> mvus-list@lists.febo.com> wrote: >>> >>>> Yep. >>>> >>>> From Tom Holmes, N8ZM >>>> >>>>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < >>>> mvus-list@lists.febo.com> wrote: >>>>> It just occurred to me that one of these nano-VNA's would >>>>> be the cat's meow for checking out attenuators and terms >>>>> at swap meets. And, to some extent, filters, too, limited >>>>> by the frequency coverage of the nano. >>>>> >>>>> Dana >>>>> _______________________________________________ >>>>> mvus-list mailing list >>>>> mvus-list@lists.febo.com >>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>> >>>> _______________________________________________ >>>> mvus-list mailing list >>>> mvus-list@lists.febo.com >>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>> >>> _______________________________________________ >>> mvus-list mailing list >>> mvus-list@lists.febo.com >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> >> >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

Nope, nor does it matter if it's an L configuration, as for a min-loss pad. It does require that the atten be all-resistive and passive however, otherwise DC measurements will not yield meaningful results. Dana On Mon, Oct 21, 2019 at 12:44 AM Tom Holmes via mvus-list < mvus-list@lists.febo.com> wrote: > Does it matter if it’s a tee or pi configuration? > > From Tom Holmes, N8ZM > > > On Oct 21, 2019, at 12:31 AM, Dana Whitlow via mvus-list < > mvus-list@lists.febo.com> wrote: > > > > Gads, no, Daun. That was more than 35 years ago! > > > > The impedance part is so simple that I remember it, > > however. The impedance of port 1, for example, is > > the geometric mean of the two resistance values > > obtained at port one as a result of shorting and opening > > port two, and vice versa. The atten value is more > > involved and I'd have to re-derive it (if I still remember > > how to do algebra). > > > > Dana > > > > > >> On Sun, Oct 20, 2019 at 9:30 PM Daun Yeagley via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >> > >> Do you still have the program? I could load it in my 41 emulator > >> program on my Android phone! > >> > >> Daun > >> Daun E. Yeagley II, N8ASB > >>> On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: > >>> Tom, > >>> > >>> 30 years or so ago, I used to carry around an HP calculator (probably > an > >>> HP41 > >>> or HP67) with a rather interesting program loaded. The idea is that > >> you'd > >>> take > >>> an attenuator under test, hook an ohmmeter to one port, and measure the > >>> resistance looking into that port for both a short and an open at the > >> other > >>> end. > >>> Enter the numbers into the calculator, then turn the attenuator around > >> and > >>> do > >>> the measurements again, and enter that pair of numbers. Hit the "go" > >>> button, and the calculator would display the characteristic impedance > at > >>> each > >>> port of the attenuator as well as the power attenuation. If the > >> impedances > >>> at > >>> both ends were correct and the attenuation value was correct, then you > >> could > >>> buy the attenuator with confidence that it had not been damaged. > >>> > >>> But the nano-VNA would be soooo much cooler! And faster, too. I wish > I > >>> had had mine at MUD 2019 a couple of weeks ago- I would probably have > >>> spent more money on attenuators and perhaps some filters as well. > There > >>> were a fair number of filters there, but I could not decode the part > >> numbers > >>> to get the bandwidths, and the nano could have helped for the lower > >>> frequency > >>> filters. > >>> > >>> Dana > >>> > >>> > >>> On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < > >>> mvus-list@lists.febo.com> wrote: > >>> > >>>> Yep. > >>>> > >>>> From Tom Holmes, N8ZM > >>>> > >>>>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < > >>>> mvus-list@lists.febo.com> wrote: > >>>>> It just occurred to me that one of these nano-VNA's would > >>>>> be the cat's meow for checking out attenuators and terms > >>>>> at swap meets. And, to some extent, filters, too, limited > >>>>> by the frequency coverage of the nano. > >>>>> > >>>>> Dana > >>>>> _______________________________________________ > >>>>> mvus-list mailing list > >>>>> mvus-list@lists.febo.com > >>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>> > >>>> _______________________________________________ > >>>> mvus-list mailing list > >>>> mvus-list@lists.febo.com > >>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>> > >>> _______________________________________________ > >>> mvus-list mailing list > >>> mvus-list@lists.febo.com > >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > >> > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >

Now I’m gonna have to start pushing my pencil just to prove it to myself. From Tom Holmes, N8ZM > On Oct 21, 2019, at 5:38 AM, Dana Whitlow via mvus-list <mvus-list@lists.febo.com> wrote: > > Nope, nor does it matter if it's an L configuration, as for a > min-loss pad. It does require that the atten be all-resistive > and passive however, otherwise DC measurements will > not yield meaningful results. > > Dana > > >> On Mon, Oct 21, 2019 at 12:44 AM Tom Holmes via mvus-list < >> mvus-list@lists.febo.com> wrote: >> >> Does it matter if it’s a tee or pi configuration? >> >> From Tom Holmes, N8ZM >> >>> On Oct 21, 2019, at 12:31 AM, Dana Whitlow via mvus-list < >> mvus-list@lists.febo.com> wrote: >>> >>> Gads, no, Daun. That was more than 35 years ago! >>> >>> The impedance part is so simple that I remember it, >>> however. The impedance of port 1, for example, is >>> the geometric mean of the two resistance values >>> obtained at port one as a result of shorting and opening >>> port two, and vice versa. The atten value is more >>> involved and I'd have to re-derive it (if I still remember >>> how to do algebra). >>> >>> Dana >>> >>> >>>> On Sun, Oct 20, 2019 at 9:30 PM Daun Yeagley via mvus-list < >>>> mvus-list@lists.febo.com> wrote: >>>> >>>> Do you still have the program? I could load it in my 41 emulator >>>> program on my Android phone! >>>> >>>> Daun >>>> Daun E. Yeagley II, N8ASB >>>>> On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: >>>>> Tom, >>>>> >>>>> 30 years or so ago, I used to carry around an HP calculator (probably >> an >>>>> HP41 >>>>> or HP67) with a rather interesting program loaded. The idea is that >>>> you'd >>>>> take >>>>> an attenuator under test, hook an ohmmeter to one port, and measure the >>>>> resistance looking into that port for both a short and an open at the >>>> other >>>>> end. >>>>> Enter the numbers into the calculator, then turn the attenuator around >>>> and >>>>> do >>>>> the measurements again, and enter that pair of numbers. Hit the "go" >>>>> button, and the calculator would display the characteristic impedance >> at >>>>> each >>>>> port of the attenuator as well as the power attenuation. If the >>>> impedances >>>>> at >>>>> both ends were correct and the attenuation value was correct, then you >>>> could >>>>> buy the attenuator with confidence that it had not been damaged. >>>>> >>>>> But the nano-VNA would be soooo much cooler! And faster, too. I wish >> I >>>>> had had mine at MUD 2019 a couple of weeks ago- I would probably have >>>>> spent more money on attenuators and perhaps some filters as well. >> There >>>>> were a fair number of filters there, but I could not decode the part >>>> numbers >>>>> to get the bandwidths, and the nano could have helped for the lower >>>>> frequency >>>>> filters. >>>>> >>>>> Dana >>>>> >>>>> >>>>> On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < >>>>> mvus-list@lists.febo.com> wrote: >>>>> >>>>>> Yep. >>>>>> >>>>>> From Tom Holmes, N8ZM >>>>>> >>>>>>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < >>>>>> mvus-list@lists.febo.com> wrote: >>>>>>> It just occurred to me that one of these nano-VNA's would >>>>>>> be the cat's meow for checking out attenuators and terms >>>>>>> at swap meets. And, to some extent, filters, too, limited >>>>>>> by the frequency coverage of the nano. >>>>>>> >>>>>>> Dana >>>>>>> _______________________________________________ >>>>>>> mvus-list mailing list >>>>>>> mvus-list@lists.febo.com >>>>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>>>> >>>>>> _______________________________________________ >>>>>> mvus-list mailing list >>>>>> mvus-list@lists.febo.com >>>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>>>> >>>>> _______________________________________________ >>>>> mvus-list mailing list >>>>> mvus-list@lists.febo.com >>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>> >>>> >>>> _______________________________________________ >>>> mvus-list mailing list >>>> mvus-list@lists.febo.com >>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >>>> >>> _______________________________________________ >>> mvus-list mailing list >>> mvus-list@lists.febo.com >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> >> >> _______________________________________________ >> mvus-list mailing list >> mvus-list@lists.febo.com >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >> > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com

All right! A good challenge to while away the morning ... I originally did the relevant analysis back around 1981 or 1982 IIRC. I had the idea of developing a formula for getting the values for a symmetrical attenuator based on terminating the far end in a short and an open, and ended up with a pair of equations in two unknowns. The solution yielded a quadratic eqn, and I had to figure out the significance of the pos & neg branches. One turned out to yield what I wanted; the other dealt with gammas of greater than unity and required a negative resistance in the circuit. So, in effect, I had discovered the bilateral negative resistance amplifier. This account is all from deep memory, and i don't guarantee its accuracy. Anyway, that effort yielded the test procedure as sort of fallout. My challenge is now to see if I can recall the math and still carry it out successfully. In this day and age one is not called upon to make much use of math skills, and mine go down the tubes pretty quickly. Dana On Mon, Oct 21, 2019 at 7:24 AM Tom Holmes via mvus-list < mvus-list@lists.febo.com> wrote: > Now I’m gonna have to start pushing my pencil just to prove it to myself. > > From Tom Holmes, N8ZM > > > On Oct 21, 2019, at 5:38 AM, Dana Whitlow via mvus-list < > mvus-list@lists.febo.com> wrote: > > > > Nope, nor does it matter if it's an L configuration, as for a > > min-loss pad. It does require that the atten be all-resistive > > and passive however, otherwise DC measurements will > > not yield meaningful results. > > > > Dana > > > > > >> On Mon, Oct 21, 2019 at 12:44 AM Tom Holmes via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >> > >> Does it matter if it’s a tee or pi configuration? > >> > >> From Tom Holmes, N8ZM > >> > >>> On Oct 21, 2019, at 12:31 AM, Dana Whitlow via mvus-list < > >> mvus-list@lists.febo.com> wrote: > >>> > >>> Gads, no, Daun. That was more than 35 years ago! > >>> > >>> The impedance part is so simple that I remember it, > >>> however. The impedance of port 1, for example, is > >>> the geometric mean of the two resistance values > >>> obtained at port one as a result of shorting and opening > >>> port two, and vice versa. The atten value is more > >>> involved and I'd have to re-derive it (if I still remember > >>> how to do algebra). > >>> > >>> Dana > >>> > >>> > >>>> On Sun, Oct 20, 2019 at 9:30 PM Daun Yeagley via mvus-list < > >>>> mvus-list@lists.febo.com> wrote: > >>>> > >>>> Do you still have the program? I could load it in my 41 emulator > >>>> program on my Android phone! > >>>> > >>>> Daun > >>>> Daun E. Yeagley II, N8ASB > >>>>> On 10/20/2019 10:14 PM, Dana Whitlow via mvus-list wrote: > >>>>> Tom, > >>>>> > >>>>> 30 years or so ago, I used to carry around an HP calculator (probably > >> an > >>>>> HP41 > >>>>> or HP67) with a rather interesting program loaded. The idea is that > >>>> you'd > >>>>> take > >>>>> an attenuator under test, hook an ohmmeter to one port, and measure > the > >>>>> resistance looking into that port for both a short and an open at the > >>>> other > >>>>> end. > >>>>> Enter the numbers into the calculator, then turn the attenuator > around > >>>> and > >>>>> do > >>>>> the measurements again, and enter that pair of numbers. Hit the "go" > >>>>> button, and the calculator would display the characteristic impedance > >> at > >>>>> each > >>>>> port of the attenuator as well as the power attenuation. If the > >>>> impedances > >>>>> at > >>>>> both ends were correct and the attenuation value was correct, then > you > >>>> could > >>>>> buy the attenuator with confidence that it had not been damaged. > >>>>> > >>>>> But the nano-VNA would be soooo much cooler! And faster, too. I > wish > >> I > >>>>> had had mine at MUD 2019 a couple of weeks ago- I would probably have > >>>>> spent more money on attenuators and perhaps some filters as well. > >> There > >>>>> were a fair number of filters there, but I could not decode the part > >>>> numbers > >>>>> to get the bandwidths, and the nano could have helped for the lower > >>>>> frequency > >>>>> filters. > >>>>> > >>>>> Dana > >>>>> > >>>>> > >>>>> On Sun, Oct 20, 2019 at 6:49 PM Tom Holmes via mvus-list < > >>>>> mvus-list@lists.febo.com> wrote: > >>>>> > >>>>>> Yep. > >>>>>> > >>>>>> From Tom Holmes, N8ZM > >>>>>> > >>>>>>> On Oct 20, 2019, at 7:39 PM, Dana Whitlow via mvus-list < > >>>>>> mvus-list@lists.febo.com> wrote: > >>>>>>> It just occurred to me that one of these nano-VNA's would > >>>>>>> be the cat's meow for checking out attenuators and terms > >>>>>>> at swap meets. And, to some extent, filters, too, limited > >>>>>>> by the frequency coverage of the nano. > >>>>>>> > >>>>>>> Dana > >>>>>>> _______________________________________________ > >>>>>>> mvus-list mailing list > >>>>>>> mvus-list@lists.febo.com > >>>>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>>>> > >>>>>> _______________________________________________ > >>>>>> mvus-list mailing list > >>>>>> mvus-list@lists.febo.com > >>>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>>>> > >>>>> _______________________________________________ > >>>>> mvus-list mailing list > >>>>> mvus-list@lists.febo.com > >>>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>> > >>>> > >>>> _______________________________________________ > >>>> mvus-list mailing list > >>>> mvus-list@lists.febo.com > >>>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >>>> > >>> _______________________________________________ > >>> mvus-list mailing list > >>> mvus-list@lists.febo.com > >>> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > >> > >> _______________________________________________ > >> mvus-list mailing list > >> mvus-list@lists.febo.com > >> http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > >> > > _______________________________________________ > > mvus-list mailing list > > mvus-list@lists.febo.com > > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com > > > _______________________________________________ > mvus-list mailing list > mvus-list@lists.febo.com > http://lists.febo.com/mailman/listinfo/mvus-list_lists.febo.com >