On Aug 22, 2019, at 21:18, Larry Rothman <ac293@...> wrote:
Carsten,
From your statement, it sounds like you only like OS s/w.
This is less of a matter of liking, but more a matter of some 40 years of experiencing the ¡°illusion of vendor support¡± (RFC 873, September 1982). Did you compile the compiler you use to create s/w exe¡¯s? Yes. If you do, what did you use - another compiler? Yes. Who compiled that one? Apple. How can you trust your compiler - or its compiler - or its assembler if you can¡¯t see back to point zero? I can¡¯t prove anything here (see Ken Thomson¡¯s 1984 Turing award acceptance speech ¡°Reflections On Trusting Trust¡±, ). On the other hand, a lot of people look at the compilation results from Apple¡¯s compilers. Did you inspect the firmware that was already installed in the NanoVNA?
Did you verify that it only provides a serial interface, and that it does not have a hidden HID interface that can inject keystrokes so fast, you¡¯d never notice? My NanoVNA is stuck in customs at the moment. But I¡¯m happy that I get to examine and compile its firmware on my own, should I choose to. I do computer security and if you¡¯re going to be paranoid and not trust just about everything 'out there' you won't get anything done. I teach information security (of which computer security is a part). Paranoia is a medical condition that is often confused by medical laymen with the mental state someone gets into who starts to understand information security. How about all the Hams that have created closed source software for the great test equipment
they¡¯ve come up with? It is their prerogative to do so. It¡¯s just not very bright. What we have learned in the field of computer science is that open source software leads to standing on the shoulders of giants, closed source software leads to others standing on your feet. (Besides, if you want to, it turns out it is easier these days to monetize the visibility you get from a good open source project than to turn a closed source software project into money. Except for very few situations that need full attention and lots, *lots* of random luck.) Your statement ¡°Being trusted always creates a liability." just doesn't cut it. Not sure you understood it. My point is that you can always choose to ¡°trust" someone. In daily personal interactions, trust may seem like a good thing for the trusted person. In reality, it also creates a liability for the trusted person: to actually be trustworthy. And that is not just about acting conscientiously, but also about being skilled enough not to get compromised. Here we don¡¯t know how that liability is being filled, which makes the trust questionable. With open source software, more people can share that liability, which can (but need not) make the trust less questionable. Gr¨¹?e, Carsten
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I've observed that it is very common for custom C# applications to trigger
a false positive on a virus scan.
That doesn't help provide a definitive answer I'm afraid, but FWIW I have
zero concerns about this application.
Roger
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On Fri, 23 Aug 2019 at 07:44, Larry Rothman <ac293@...> wrote: has a great list of articles on tests
they've performed on the most popular AV s/w.
It's a nice site for research - they publish their test methods as well.
For 2018, Microsoft had the most false +'s but that is to be expected from
them as they want to safeguard the family jewels.
In any case, this is becoming noise in this forum - back to the NANO!!!
Anyone look at my housing design?
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If you're paranoid, back up your machine regularly.
Actually, you should do that if you aren't paranoid.
And if you think somebody else should have released the fruits of their efforts as open source,
then perhaps your best path forward is to spend a few months creating an open source replacement for it.
That said, I'm truly grateful that the firmware on the nanoVNA itself is open source.
Gives us an excellent platform for developing it further.
Kudos to edy555 and Hugen.
Jerry, KE7ER
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On Thu, Aug 22, 2019 at 12:18 PM, Larry Rothman wrote: Your statement "Being trusted always creates a liability." just doesn't cut it.
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Further Comments on Resistive Bridges
As discussed in prior posts the NanoVNA uses a resistive bridge.
They are wide band and easier to construct then the alternative
bridge utilizing a directional coupler.
There are excellent references on the resistive bridge. The RF
bridge being a variation of the well know Wheatstone Bridge.
An excellent treatment and discussion is presented in
"The Wheatstone Bridge:How Does It Impact VNA Measurements"
Author: Brian Walker. Presented in RF and MIcrowave Magazine.
Further work in this area is presented by Joel Dunsmore and appears
in RF design Magazine Nov 91, "Simple SMT Bridge Circuit Mimics
Ultra Boradband Coupler".
I decided to calculate the port impedance of the NanoVNA R bridge.
It is 51.27 ohms and within the specified SWR source match.
Using this bridge as a template and based on a OPAMP version
of a similar bridge, I constructed a simple Spice Version. This schematic
is attached. The simulation is run in LTSpice. A free down load of this
simulator is available from Analog Devices web. A nice treatment of this
bridge and running it in simulation is instructive! You can plot Gamma as well return loss.
See a paper by Dunbar published in Electronic Design May 29, 2000, "Build A Vector Network Analyzer".
There the discussion presents VNA's which can span audio through RF and
includes functions like metal detectors, microphone analysis, etc... This
circuit operated in Spice simulation is handy to check the understanding of what the
NanoVNA returns in measurements.
I'll see if I can place the LT Spice circuit file in a folder for those interested.
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has a great list of articles on tests they've performed on the most popular AV s/w.
It's a nice site for research - they publish their test methods as well.
For 2018, Microsoft had the most false +'s but that is to be expected from them as they want to safeguard the family jewels.
In any case, this is becoming noise in this forum - back to the NANO!!!
Anyone look at my housing design?
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FWIW both a fresh download of NanoVNAsharp and one from July come up clean with BitDefender, which doesn't seem to be included in virustotal scans.
Quite a few antivirus companies share technology ag Avast = AVG, so it is possible your 'different' security programs use the same code base.
Mike
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-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Bob Kozlarek Sent: 22 August 2019 14:45 To: [email protected]Subject: [nanovna-users] NanoVNAsharp I wanted to download the PC software, nanovnasharp from Hugen's Google drive. Tried it on 2 pcs, and both using different security programs flagged it as a potential ransomware program. Can anyone provide a site from which the files are clean? I'm assuming that this is the only software that is available?
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Carsten,
From your statement, it sounds like you only like OS s/w. Did you compile the compiler you use to create s/w exe's? If you do, what did you use - another compiler? Who compiled that one? How can you trust your compiler - or its compiler - or its assembler if you can't see back to point zero?
Did you inspect the firmware that was already installed in the NanoVNA?
Did you verify that it only provides a serial interface, and that it does not have a hidden HID interface that can inject keystrokes so fast, you'd never notice?
I do computer security and if you're going to be paranoid and not trust just about everything 'out there' you won't get anything done.
How about all the Hams that have created closed source software for the great test equipment they've come up with?
Your statement "Being trusted always creates a liability." just doesn't cut it.
Regards,
Larry
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On Aug 22, 2019, at 16:46, Larry Rothman <ac293@...> wrote:
Hugen wrote the application spcifically for the nanoVNA and it is closed source.
Which doesn¡¯t protect us from him catching something that then is compiled into all executables he makes. Yes, that has happened to others. Being trusted always creates a liability. (And the closed source nature heavily increases the amount of trust required.) Gr¨¹?e, Carsten
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Larry,
This is a good test site. It¡¯s known that some specific AV programs have false positives for miscellaneous programs that other AV test approaches do not. It¡¯s why, for instance, Wes Hayward doesn¡¯t distribute the software to his popular RF circuit design book any longer ;and the ARRL has removed the CD from the book, too).
I sent out a PDF newsletter to my club that I got monthly from a club in Texas and all hell broke loose because one member used Avast which had a know false positive whereas all other AV software didn¡¯t. So your use of the above website is a great tool to check these issues.
73,
Frank
K4FMH
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On Aug 22, 2019, at 9:46 AM, Larry Rothman <ac293@...> wrote:
I don't know what you're using for AV but virustotal gets 0 hits:
The nanoVNA Wiki has the google drive link for the software:
Hugen wrote the application spcifically for the nanoVNA and it is closed source.
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I don't know what you're using for AV but virustotal gets 0 hits:
The nanoVNA Wiki has the google drive link for the software:
Hugen wrote the application spcifically for the nanoVNA and it is closed source.
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I wanted to download the PC software, nanovnasharp from Hugen's Google
drive. Tried it on 2 pcs, and both using different security programs
flagged it as a potential ransomware program. Can anyone provide a site
from which the files are clean?
I'm assuming that this is the only software that is available?
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Re: Quick compare with HP 8753C...
Roger, I had a thought...
I think I might try your same technique of external calibration for my original test (per the first post in this message thread).
In other words, using both the NanoVNA and the 8753C, like you, I would capture s2p (or s1p?) files for each of my SOL loads, and then capture, uncorrected, the S11 data for my tuner. And then use this data and the correction formulas to create corrected s1p files for each VNA.
I haven't used Python (well, not for a very long time), but I'm thinking I could do it with a Matlab script. I know that one of Dick Benson's files on the Matlab Central website has a 10-point correction script (it's in the 3577A utility -- and it is only 10 points, rather than 12, because he skips the isolation measurements).
I'd need to figure out what the correction formula is for S11 -- I'm assuming it's a 3-point correction. But if I can do that, then I should be able to accomplish this goal. I'm very interested to see what the results would be, and how they differ from measurements made on the VNAs after they've been cal'd.
Anyway -- this won't happen until early next week, as the wife and I are off to Seattle to see her son.
- Jeff
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Re: New to group and thoughts on Return Loss and Loss
I am on holiday so did follow the various threads recently.?A bridge or Directional coupler is the heart of any VNA. Strictly speaking if you are serious, the bridge or coupler ought to be characterised carefully before you make any accurate measurements. A standard Return loss bridge is a three post device. in others like the nanovna it is in fact a 4 port device. In, out, return mag and input phase. So in principle you should require S11, S12... A 4x4 matrix with 16 components. Only a masochist would want to go about doing all these measurements. FOR most common purposes it is also not necessary. Nevertheless the information may be necessary depending on what you are doing.?That 12dB inherent bridge loss for open/short loads is related to the above 16 parameters. It is not nonsense. Theoretically you can work out that it's 12.014.. dB but as frequency increases it's value increases, it never decreases. That is why we zero it out, but there is a price. Assuming your detector can get down to 92dB (dynanic range) then at dc you will have a directivity of 80dB but as? frequency increases this drops. The directivity is the maximum range, the largest RL value you can measure with the instrument, provided it is properly calibrated.? In some cases if you want to do S11, S21 in line measurements this calibration is non trivial. at his is why professional talk about 12 points and 16 point calibration procedures etc.?For causal work a 3 point is quite adequate, in fact the minvna uses only 1 point calibration and I am ok with it for casual antenna work.Incidentally a RL of 70dB corresponds to 1.00063 vswr or a reflection coeff magnitude of 0.00031.? If anybody claims that the nanovna can measure these values accurately at even 10MHz, as Dr Kirby has objected,? then I would like to see some hard evidence.Hope this helps with the discussion. I now rather look forward to my Prague appointment for the Mozart: Don Giovanni opera, in the Opera House where he first debut it to the world in 1787.Sent from my Samsung Galaxy smartphone.
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-------- Original message --------From: Warren Allgyer <allgyer@...> Date: 22/08/2019 01:00 (GMT+01:00) To: [email protected] Subject: Re: [nanovna-users] New to group and thoughts on Return Loss and Loss When using a spectrum analyzer/tracking generator/RF bridge to make S11 measurements, part of the setup is to normalize the results to zero with an open at the DUT port. This the the analog of the ¡°O¡± calibration of the VNA.A reading of ¡°-12 dB¡± or, in my case, -19 dB¡¡ is simply the inherent loss of the bridge and it must be normalized out if you need a direct reading of RL or used as an offset for the uncalibrated reading.Return losses of DUT at the far end of a coax line require calibration at that end, not at the device itself.WA8TODOn Aug 21, 2019, at 4:23 PM, Stuart Landau via Groups.Io <stuartl73@...> wrote:Return loss is a very old term used in the telephone industry for a very long time. There is confusion about the sign, but the negative has been used as long at the term return loss has been in use. Most of us understand the meaning and implications.The 12 dB nonsense came up in a 100% reflection measurement because of losses in the RL bridge, but it's meaningless.The reference for either an open or short is a return loss of zero. The bridge losses should only reduce the dynamic range of a measurement, not the accuracy.However, if you have any transmission loss between the RL measuring device and the 100% reflection, it will give you a better return loss than zero.If a coax has a 3dB loss for instance, it will show (in theory) a 6 dB return loss because the RF will travel twice through a 3dB loss (the coax).Stuart K6YAZLos Angeles, USA-----Original Message-----From: Hans J Albertsson <hans.j.albertsson@...>To: nanovna-users < [email protected]>Sent: Wed, Aug 21, 2019 11:33 amSubject: Re: [nanovna-users] New to group and thoughts on Return Loss and LossA loss is a negative gain.So, saying a return loss is negative simply means you are expressing thatloss as a formal gain.Don't overdo the besserwisserness of your insights.Den ons 21 aug. 2019 20:07Ron Spencer via Groups.Io <ron.spencer@...> skrev:> Interesting topics being discussed.> > > > I was surprised to read that the RL from a short or open is 12.XXXdB. That> just isn't true, ever (assuming, of course, lossless feedline/ connectors).> Its 0. Always will be. Energy sent down the feedline to either the short or> open has "no where" to go so is 100% reflected.> > > > I also read loss is always negative? When calculating power out of a> system sure. But when expressing it (such and such feedline has XdB of> loss) its always a positive number. Negative loss implies gain.> > > > I see this often so I can readily understand how folks can get this wrong.> Professionals get it wrong. I saw one commercial (not for ham radio)> amplifier maker have a graph of return loss labeled in -Db.> > > > All that said, I find the nanovna a very useful device. Much easier to> bring to the tower base than my HP 8753. I look forward to using it more.> > Sent using > > > >
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Running Nanovnasharp on macOS with wine
I have a nanovna (black) and am tickled with the way it works.
I¡¯ve been able to re tune a nice 4 Mhz wide filter for 144 Mhz that had been damaged.
I have the software running under windows10
but I was wondering if anyone has been able to get it going with Wine on macOS majave?
I would appreciate some directions as to how you did it as I have not been able
to get it to run yet.
Thanks
Dana VE3DS
Toronto
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Re: Measuring Common Mode Rejection
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Re: Quick compare with HP 8753C...
Great stuff, that matches up very nicely :)
Roger
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On Thu, 22 Aug 2019 at 12:31, Jeff Anderson <jca1955@...> wrote: Roger, I think everything is fine.
Using a cursor placed on my plots, I can step through the Return Loss for
each point. Here's what I see for the last 10 points for each capture:
Nano 8753
------------------
10.98 10.97 <- 273.27 MHz
10.98 10.97
10.97 10.97
10.96 10.96
10.96 10.96
10.98 10.96
10.98 10.96
10.96 10.95
10.95 10.95
10.94 10.95 <- 300 MHz
Discounting the rounding, these seem to trend pretty close (to me) to the
data shown in your plot. And note that the Nano data is noisier than the
8753C data, which matches what you show, too.
- Jeff
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Re: Quick compare with HP 8753C...
Roger, I think everything is fine.
Using a cursor placed on my plots, I can step through the Return Loss for each point. Here's what I see for the last 10 points for each capture:
Nano 8753
------------------
10.98 10.97 <- 273.27 MHz
10.98 10.97
10.97 10.97
10.96 10.96
10.96 10.96
10.98 10.96
10.98 10.96
10.96 10.95
10.95 10.95
10.94 10.95 <- 300 MHz
Discounting the rounding, these seem to trend pretty close (to me) to the data shown in your plot. And note that the Nano data is noisier than the 8753C data, which matches what you show, too.
- Jeff
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Re: New to group and thoughts on Return Loss and Loss
On Wed, Aug 21, 2019 at 03:21 PM, Ron Spencer wrote:
Return loss tells you how much of the input signal is reflected. Return loss
is the ratio between the reflected power and input power:
Hi Ron, Be careful here about mixing power definition into return loss calculations. Strictly speaking the Gamma value or reflection coefficient is defined as a ratio of (V_reflected/V_incident). Again, the magnitude of the value of Gamma provides the value of RHO that I posted earlier. In a matched system you could certainly bring power into the definition but what about systems where impedance are mixed? I think you will avoid problems if you stick to VOLTAGE throughout your discussions of return loss and S11. Note, S11 is just GAMMA and as such like GAMMA is characterized with a magnitude value and a phase value. And the magnitude of S11 is just RHO. Gee, I hope I have no typos again... Alan
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Re: Quick compare with HP 8753C...
Nice work. And yes there is no problem with a healthy dose of sceptisicm.
Particularly when results look too good to be true :)
I will double check tonight, to make sure I haven't done something stupid.
Its so easy to be fooled doing this stuff.
This is a Hugen NanoVNA FWIW.
Roger
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On Thu, 22 Aug 2019 at 10:47, Jeff Anderson <jca1955@...> wrote: Thanks, Roger. Apologies for the extra work.
Smith chart plots are attached. One is "full-view", the other is
zoomed-in.
Even zoomed-in, I cannot tell any difference between the two. In fact,
they are so identical that I at first suspected the files might
accidentally have been the same, but they are not.
- Jeff
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Re: New to group and thoughts on Return Loss and Loss
Yes, Jeff. My typo error. Should be GAMMA not RHO!
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K4FMH
F4WCV