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Re: NanoVNA-Saver 0.1.3
Hi Herb,
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I don't see an attachment :-) I have attempted to make the code more resilient to that particular phenomenon, so if you can describe the exact steps that cause it, that would be most appreciated! -- Rune / 5Q5R On Wed, 16 Oct 2019 at 20:24, hwalker <herbwalker2476@...> wrote:
Rune, |
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Re: NanoVNA-Saver 0.1.3
Hi Mel,
I'm not entirely sure what you wanted to say with your comment, which needed to be said, though? Was it related to series R + X, as requested by Martin? I'm not sure where the Smith chart comes into it? -- Rune On Wed, 16 Oct 2019 at 19:59, Mel Farrer, K6KBE <farrermesa@...> wrote: The current display is in smith chart with Magnitude and phase, and or on |
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Re: NanoVNA-Saver 0.1.3
A standard PC USB HD camera connected to your PC should be able to be re-focused for close-up work.You just need a stand to hold it above the item you're working on.Even the cheap ones from the dollar store should work if they are 640x480 or better.Just make sure they are the newer typeas that don't need any drivers (ie: UVC compatable)
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Or - you can get an old stereo microscope from any surplus equipment store. Regards, Larry On Wednesday, October 16, 2019, 2:54:02 p.m. GMT-4, N9KDY <n9kdy@...> wrote:
W5DXP wrote: Thanks Rune, when I said "considerable improvement" I was talking about the better visibility it provides OFs like me with macular degeneration, cataracts, etc.Yeah.? Me too.? Add in presbyopia to the "et cetera."? Which is where soldering a couple of less-than-rice-grain-sized resistors for the USB-C port fix becomes ... problematical. Luckily, I still have all my SMD soldering tools.? But I also now have a 10-diopter fluorescent-ring-tube-lighted 25cm-diameter magnifying glass which might allow me to attempt it. -- Wes Will N9KDY |
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Re: NanoVNA-Saver 0.1.3
Mel Farrer, K6KBE
The current display is in smith chart with Magnitude and phase, and or on
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SWR just that, No R and j. R is the resistive component of the signal and j is the computed reactive element in ohms of the phase. Yes, we can do it off line of course, but both of my other VNA units will give me the R and j directly. Being a RF nut, I don't use Smith charts in the design of anything I use the R an j. The Smith chart is good for many things, but I don't use it, I prefer to look at the Magnitude and the j as it is displayed in a swept response of frequency. That is, I am mostly interested in the j0 crossover that is the resonance of the load I am putting into the analyzer. Example: if I want to know the resonant frequency of a antenna, I do not look for min SWR. That tells me nothing. Once I know the j0 frequency, I then can address matching the R magnitude and I am done..... Sorry for the long comment, but I think it needed to be said. Cheers, Mel, K6KBE On Wed, Oct 16, 2019 at 10:29 AM Rune Broberg <mihtjel@...> wrote:
Hi Martin, |
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Re: Any ideas for test jigs?
Getting Ft from measured S data is pretty straight forward. The key is you DO NOT NEED TO MEASURE TO THE POINT OF UNITY CURRENT GAIN!
Simply take a couple of points say at 10 MHz and 100 MHz. You will need the full 2 port S data at 10 and 100 MHz. Then convert that data to H parameters and fetch the h21 parameter. Check to be sure that the roll off rate between 10 and 100 MHz is 20 dB. It should be, if not you have a fundamental problem from the get go. Then simply extrapolate the roll off until the h21 parameter goes to unity. Viola' the ft value. If you need clarification on this stuff, let me know. |
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Re: NanoVNA-Saver 0.1.3
W5DXP wrote:
Thanks Rune, when I said "considerable improvement" I was talking about the better visibility it provides OFs like me with macular degeneration, cataracts, etc.Yeah. Me too. Add in presbyopia to the "et cetera." Which is where soldering a couple of less-than-rice-grain-sized resistors for the USB-C port fix becomes ... problematical. Luckily, I still have all my SMD soldering tools. But I also now have a 10-diopter fluorescent-ring-tube-lighted 25cm-diameter magnifying glass which might allow me to attempt it. -- Wes Will N9KDY |
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NanoVNA WebApp USB question
I have downloaded the NanoVNA WebApp to my Samsung S8 which has a USB C connector.
I've read issues about USB C to USB C connection issues without the 5.1k pullup resistors so I want to get a USB-C to USB-A female OTP cable to use with the USC-A to USB-C cable supplied with my nanoVNA. Are there any issues if a get a USB-C to USB-A 3.1 female OTP cable or should I get a USB-C to USB-A 2.0 female OTP cable ? Thanks, Mike N2MS |
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Re: NanoVNA-Saver 0.1.3
Thanks, I'll get that fixed in the next version :-) Didn't catch that one
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during the testing, clearly ;-) -- Rune / 5Q5R On Wed, 16 Oct 2019 at 18:56, W5DXP <w5dxp@...> wrote:
Thanks Rune, when I said "considerable improvement" I was talking about |
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Re: NanoVNA-Saver 0.1.3
W5DXP
Thanks Rune, when I said "considerable improvement" I was talking about the better visibility it provides OFs like me with macular degeneration, cataracts, etc. However, I think there is a slight bug in the graph line widths. When I launch saver, it remembers what line width I previously selected but it doesn't implement it until I make a new change to the line width.
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Re: NanoVNA-Saver 0.1.3
Right click the charts. :-)
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-- Rune / 5Q5R On Wed, 16 Oct 2019 at 18:42, W5DXP <w5dxp@...> wrote:
Sorry, I can't seem to locate the fixed scaling options. Where are they? |
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Re: NanoVNA-Saver 0.1.3
You're right, Raymond! I forgot about that. I still need to do *more* with
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it - it breaks in places. But I guess as long as people don't complain about it ... ;-) -- Rune / 5Q5R On Wed, 16 Oct 2019 at 18:37, Raymond Domp Frank <hewpatek@...> wrote:
On Wed, Oct 16, 2019 at 02:38 PM, Rune Broberg wrote:One "minor change" I like a lot is the better handling of the (X-axis) |
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Re: NanoVNA-Saver 0.1.3
On Wed, Oct 16, 2019 at 02:38 PM, Rune Broberg wrote:
One "minor change" I like a lot is the better handling of the (X-axis) numerals in my graphs. Say, I'm using a span of 100 kHz around 20 MHz. "Return loss" and "Gain" graphs now show two decimals where it makes sense. Previously, all X-axis points were shown as "20.0 M", whereas now they go from "19.95M" to "20.05M" and the center point still shows "20.0M". Neat. Raymond |
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Re: Abbreviated documentation for more simplistic tasks?
Maybe, "Find the resonant frequency of thisIf you check out Wiki Application Notes, then you will discover some are simply links to useful messages. If "Application Notes" seems too stuffy or ambitious, we could start a Wiki "How-To" page. Keep in mind key word search from /g/nanovna-users/wiki and /g/nanovna-users/messages FWIW, "resonant frequency" gets no hits in Wiki, but 17 in Messages; sorting and supplementing those might yield a useful HowTo or three... |
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Re: Any ideas for test jigs?
jim
Very nice ...Several of the older data books also show test circuits for individual transistors ...I've been contemplating making some measurements of Ft/Ic for various known/unknown...unknown/unknown transistors
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Maybe I should build something... Jim On Wednesday, October 16, 2019, 8:34:05 AM PDT, alan victor <avictor73@...> wrote:
Please take a look at hp application note 77-1. Transistor Parameter Measurements. Info in the note still applicable today as well to passive devices. Yes, you need to take care that the device input power CH0 is reduced from the -9 to -12 dBm power level. Say, -20 to -30 dBm.? As well, the output power set by the DUT gain is not excessive as delivered to CH1. In AN 77-1, the grand daddy of the vna, the vector voltmeter is discussed, however, test fixtures and the application of the bias tee network is presented. Note 2- directional couplers are featured on the cover. The vna you use has in effect only one of those couplers (a resistor bridge). Hence you need to turn the device around to obtain the remaining s data. Or, see another post where another user has built a switch function for doing this task. Also, see LT Spice simulator which is free. LT handles active devices with models and provides S parameter output data. So you can run a simple 2N3904 at 30 MHz or so,? where package parasitic of the transistor is not so critical and see the expected results. There is quite a bit of information to digest before you can expect to get measured results to agree with calculation. However, the eureka moment is sure worth the effort! FUN. |
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Re: NanoVNA-Saver 0.1.3
W5DXP,
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thanks - don't make it sound like it was horrible before ;-) -- Rune / 5Q5R On Wed, 16 Oct 2019 at 18:03, W5DXP <w5dxp@...> wrote:
Many thanks, Rune, IMO a considerable improvement. |
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Re: NanoVNA-Saver 0.1.3
Hi Martin,
I want to do more things with markers, including having the ability to add more of them, and/or to change what information is being displayed. Not sure it will be in the next release, but it's on the list. I am a little confused, though - my background is not (at all) in RF tech: Isn't Series R & X = Z? Which is already displayed? Or what are we talking here? -- Rune / 5Q5R On Wed, 16 Oct 2019 at 17:18, Martin via Groups.Io <martin_ehrenfried= [email protected]> wrote: Hi Rune, |
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