Re: Smith's book. free download
thank you On Fri, Aug 5, 2022 at 1:38 PM Larry McElhiney via groups.io <lmcelhiney= [email protected]> wrote: Free PDF download here:
Just downloaded it.
Larry
AC9OX
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Re: NanaVNA H4 battery indicator shows full but unit powers off after a minute
Scott,
This may not help, but try leaving it charging overnight and see if that helps. It could be just the battery went bad.
73,
Cliff, AE5ZA
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On Aug 5, 2022, at 15:10, Scott Ginsburg <k1oa@...> wrote:
My battery indicator icon shows a full charge but the unit turns off after about a minute.
I charged it for about 5 minutes, unplugged the USB cable and it stayed on for about the same amount of time then turned off again, acting as if it needed a charge.
I have seen the indicator show a partial charge in the past.
I haven't used it in a few months, don't recall how much charge was on it when it was last used.
Is this a known issue?
tnx and 73,
Scott
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NanaVNA H4 battery indicator shows full but unit powers off after a minute
My battery indicator icon shows a full charge but the unit turns off after about a minute.
I charged it for about 5 minutes, unplugged the USB cable and it stayed on for about the same amount of time then turned off again, acting as if it needed a charge.
I have seen the indicator show a partial charge in the past.
I haven't used it in a few months, don't recall how much charge was on it when it was last used.
Is this a known issue?
tnx and 73,
Scott
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Re: Smith's book. free download
Here are the ISBN numbers for his book:
ISBN: 1-884932-39-8?
ISBN 13: 978-1-8849-3239-7
You may be able to find an electronic copy by searching the ISBN
numbers. ?I hope that helps.
Sincerely,
Everett McArthur
KE5QVC
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On Fri, 2022-08-05 at 19:39 +0000, W0LEV wrote: Thank's, Jim (Lux)!? I'm an old fart (75) and still much prefer a
printed
copy.?? With ARRL so non-technical these days, I seriously doubt we
could
convince them to, once again, carry the reprints?
At the time, $400 was all I had in my pocket in travel money from my
employer.? He knew what he had!!!? I'll never forget that meeting.? I
can
still review it in my mind's eyes......
Dave - W?LEV
On Fri, Aug 5, 2022 at 7:34 PM Jim Lux <jimlux@...> wrote:
On 8/5/22 11:38 AM, Charles Young wrote:
Smith Chart lovers:
A few months ago I downloaded a free copy of Mr. Smith¡¯s book. I
have
mislaid the URL. Keep looking. I am sure you will find it.
Chuck KF8TI
"Electronic applications of the Smith Chart
in waveguide, circuit and component analysis"
Phillip H Smith
It's not on archive.org
--
*Dave - W?LEV*
*Just Let Darwin Work*
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Re: upgrade old version NanoVNA H vers 3.4
Hi, I know the config DFU setting, but with my HW modification it is even faster to enter DFU mode - switch off, press the jog, switch on, release the jog - this helps me when I test my own FW modifications - and more important this works also when something goes wrong and the device doesn't respond anymore (luckily you cannot brick the NanoVNA, because the bootloader is built in HW and cannot be damaged).
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Re: Smith's book. free download
Free PDF download here:
Just downloaded it.
Larry
AC9OX
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Re: Smith's book. free download
On 8/5/22 12:39 PM, W0LEV wrote: Thank's, Jim (Lux)! I'm an old fart (75) and still much prefer a printed
copy. With ARRL so non-technical these days, I seriously doubt we could
convince them to, once again, carry the reprints? I'm not sure it would really be worth it - there are lots of later books which might have a better tutorial. So you'd be possessing it for its historical significance - for which the $400 might be reasonable. Amazon will sell you a copy for $90, hardcover, as an import from 1969. Abebooks will sell you various copies for more. They've got a first edition, fifth printing for $854 I used to use Bowick's RF Circuit Design which I see on Amazon is about $42 for the 2nd edition. Something like that might be a better choice for someone starting out.
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Re: Smith's book. free download
Thank's, Jim (Lux)! I'm an old fart (75) and still much prefer a printed
copy. With ARRL so non-technical these days, I seriously doubt we could
convince them to, once again, carry the reprints?
At the time, $400 was all I had in my pocket in travel money from my
employer. He knew what he had!!! I'll never forget that meeting. I can
still review it in my mind's eyes......
Dave - W?LEV
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On Fri, Aug 5, 2022 at 7:34 PM Jim Lux <jimlux@...> wrote: On 8/5/22 11:38 AM, Charles Young wrote:
Smith Chart lovers:
A few months ago I downloaded a free copy of Mr. Smith¡¯s book. I have
mislaid the URL. Keep looking. I am sure you will find it.
Chuck KF8TI
"Electronic applications of the Smith Chart
in waveguide, circuit and component analysis"
Phillip H Smith
It's not on archive.org
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
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Re: Smith's book. free download
On 8/5/22 11:38 AM, Charles Young wrote: Smith Chart lovers:
A few months ago I downloaded a free copy of Mr. Smith¡¯s book. I have
mislaid the URL. Keep looking. I am sure you will find it.
Chuck KF8TI
"Electronic applications of the Smith Chart in waveguide, circuit and component analysis" Phillip H Smith It's not on archive.org
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Smith's book. free download
Smith Chart lovers:
A few months ago I downloaded a free copy of Mr. Smith¡¯s book. I have
mislaid the URL. Keep looking. I am sure you will find it.
Chuck KF8TI
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On Aug 5, 2022, at 2:14 PM, W0LEV <davearea51a@...> wrote:
Again, that's why SimSmith is an indispensable tool when dealing with
complex impedances and over different frequencies. It is a universal
presentation tool in the professional RF and microwave world.
In my career, I once and only once ran across another engineer who had an
ORIGINAL publication by Mr. Smith of his book which introduced the Smith
Chart in the mid 1950's and its multiple uses. I offered him $400
on-the-spot. Unfortunately he knew what he had. He refused my offer!!
?? Several decades ago ARRL used to offer a reprint which I had but lost
in a forest fire. They no longer offer it.
Dave - W?LEV
On Fri, Aug 5, 2022 at 5:42 PM F1AMM <18471@... <mailto:18471@...>> wrote:
And I say that if we represented the Smith as attached, it would be much
clearer. This is also how we project impedances on the Smith.
It has, in addition, the great interest of materializing the S11 that we
wonder, a little, why we were to invent that. The Smith diagram was
invented when there were no computers. Placing an impedance using the
abacus is tedious and very inaccurate. On the other hand, presenting the
impedances on the chart shows a good synthesis.
However, do not forget that the chart was designed for work at a fixed
frequency. We generally use it at variable frequency and the cursors are
essential to identify the frequency. Or you have to label points on the
graphs
--
F1AMM (Fran?ois)
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
Dave - W?LEV
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Re: At which point do we take the value of impedance to tune an antenna?
Again, that's why SimSmith is an indispensable tool when dealing with
complex impedances and over different frequencies. It is a universal
presentation tool in the professional RF and microwave world.
In my career, I once and only once ran across another engineer who had an
ORIGINAL publication by Mr. Smith of his book which introduced the Smith
Chart in the mid 1950's and its multiple uses. I offered him $400
on-the-spot. Unfortunately he knew what he had. He refused my offer!!
?? Several decades ago ARRL used to offer a reprint which I had but lost
in a forest fire. They no longer offer it.
Dave - W?LEV
toggle quoted message
Show quoted text
On Fri, Aug 5, 2022 at 5:42 PM F1AMM <18471@...> wrote: And I say that if we represented the Smith as attached, it would be much
clearer. This is also how we project impedances on the Smith.
It has, in addition, the great interest of materializing the S11 that we
wonder, a little, why we were to invent that. The Smith diagram was
invented when there were no computers. Placing an impedance using the
abacus is tedious and very inaccurate. On the other hand, presenting the
impedances on the chart shows a good synthesis.
However, do not forget that the chart was designed for work at a fixed
frequency. We generally use it at variable frequency and the cursors are
essential to identify the frequency. Or you have to label points on the
graphs
--
F1AMM (Fran?ois)
-- *Dave - W?LEV* *Just Let Darwin Work*
--
Dave - W?LEV
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Re: At which point do we take the value of impedance to tune an antenna?
And I say that if we represented the Smith as attached, it would be much clearer. This is also how we project impedances on the Smith.
It has, in addition, the great interest of materializing the S11 that we wonder, a little, why we were to invent that. The Smith diagram was invented when there were no computers. Placing an impedance using the abacus is tedious and very inaccurate. On the other hand, presenting the impedances on the chart shows a good synthesis.
However, do not forget that the chart was designed for work at a fixed frequency. We generally use it at variable frequency and the cursors are essential to identify the frequency. Or you have to label points on the graphs
--
F1AMM (Fran?ois)
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Re: upgrade old version NanoVNA H vers 3.4
hi HO-Ro - thanks for the reply. Currently with the firmware of dslord 20211230 it works for me (I also noticed that it has many new parameters,) I was wondering if this firmware was the ideal one, that's all. I didn't need to make internal jumpers, because to enter DFU mode and upgrade the nanovna, I just need to do it from the CONFIG submenus. Since I purchased it, I have only made one firmware update, always entering the CONFIG submenus. I think perhaps that with previous firmware of my version it needed to open the cover and make jumpers to be able to enable the update mode
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Re: New owner of nanovna-H and H4, However pondering the next step in precision
On 8/5/22 8:17 AM, F1AMM wrote: The "raw measurement" that the NanoVNA makes is essentially a filtered sum of 48
samples. [...] Thank you very much for this explanation. To say that I understand everything would be inaccurate but I now understand the principle.
I will integrate your text (in French :)) in my summary document that I am currently writing on the use of nanaoVNA. My document is called:
? A nanaoVNA but it's very simple ? a postiche to Eug¨¨ne Aisberg's book: "La radio mais c'est tr¨¨s simple" (The radio but it's very simple)
It's far from over but this chapter was missing
No problem.. The whole "uncertainty analysis" for a VNA can be remarkably complex - people spend their entire life researching it, getting a PhD along the way. If you think about something simple, like a voltmeter, there's typically two kinds of uncertainty - the "% of full scale" kind of thing (usually related to resolution) and the "% of measurement" (scale factors). But it's pretty simple for something like an ohmmeter or voltmeter. The "equation" for the DMM is something like DigitalNumber * Calibration Scale Factor = Number in Engineering Units. You've got an uncertainty in the Digital Number (raw measurement), you've got an uncertainty in the scale factor (how many millivolts per LSB), maybe an offset, and that's about where it ends. Calibrated Voltage = (Scale factor +/- uncertainty) * (raw measurement +/- uncertainty) + (offset +/- uncertainty) Even on a power meter, you need to roll in things like the mismatch uncertainty, but it's still fairly simple. Calibrated Power = [(Scale factor +/- uncertainty)* (raw measurement +/- uncertainty) + (offset +/- uncertainty)] * (mismatch +/- uncertainty) But here, you've got not only the resolution/accuracy issue on the underlying measurement, the effects of the Unit Under Test, and the significantly more complex calculation involved in turning the raw measurement into a calibrated S11 measurement. here's the equations from the NanoVNA firmware - each of the inputs has some uncertainty associated with it. static void apply_error_term_at(int i) { // S11m' = S11m - Ed // S11a = S11m' / (Er + Es S11m') // CAUTION: Et is inversed for efficiency // S21m' = S21m - Ex // S21a = S21m' (1-EsS11a)Et }
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Re: At which point do we take the value of impedance to tune an antenna?
Roger, you make an excellent point. I would however like to point out that I believe your 100 +j0 and 25 +j0 are swapped. 25 should be on the left side and 100 should be on the right side of the graph. Am I wrong? Still trying to learn Smith Charts.
73 Mike N7ATC
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Re: New owner of nanovna-H and H4, However pondering the next step in precision
The "raw measurement" that the NanoVNA makes is essentially a filtered sum of 48
samples. [...] Thank you very much for this explanation. To say that I understand everything would be inaccurate but I now understand the principle. I will integrate your text (in French :)) in my summary document that I am currently writing on the use of nanaoVNA. My document is called: ? A nanaoVNA but it's very simple ? a postiche to Eug¨¨ne Aisberg's book: "La radio mais c'est tr¨¨s simple" (The radio but it's very simple) It's far from over but this chapter was missing -- F1AMM (Fran?ois) -----Message d'origine----- De la part de Jim Lux vendredi 5 ao?t 2022 14:13
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Re: New owner of nanovna-H and H4, However pondering the next step in precision
On 8/4/22 11:55 PM, F1AMM wrote: Hello
I follow your discussion with interest but my language is not English - thank you Google. If you could avoid using acronyms such as "ADC". What does it mean ?
Could you develop a little more what follows sure.. ----o----
One other thing..
The "raw measurement" that the NanoVNA makes is essentially a filtered sum of 48 samples. The raw adc samples are probably about 1 part in 10^4 (call it 1E-4 fractional uncertainty) so 48 samples will be sqrt(N) better, or 1.4E-5. (ignoring arithmetic precision). The way the NanoVNA receivers work is by taking the input signal and mixing it with a LO that is 5 kHz away and doing an analog low pass filter. That audio 5 kHz signal is fed into a standard multichannel audio codec[1]. The audio signal is sampled into 16 bit samples at 48 kHz for 1 millisecond. The Analog to Digital Converter (ADC) in the particular chip used is a bit tricky, but it's easiest to think of it as a straight 16 bit ADC, with a specified noise SNR of 80dB (min) 95 dB (typ), and a THD+N spec of -85 dB (typ) -70dB (max). 80 dB is 1 part in 10,000 for voltage. So I assume that each sample has an uncertainty of 1E-4 full scale. That is, if I put 1 volt into the digitizer, the samples have rms noise of 0.1 mV. (This is approximate, there's lots of caveats on this). If you average a bunch of samples, the noise voltage is reduced by a factor of sqrt(N), where N is the number of samples. So the estimated noise is 0.0144 mV, not 0.1 mV. But to turn that into an uncertainty on a measurement, we need to know the level of the signal. We know the noise (after averaging) is 0.0144mV, but we're probably not putting a full scale signal in. I assumed we'd put in 0.1*full scale. So our measurement uncertainty is 0.0144 mV out of 100 mV. [1] The ADC is a TLV320AIC3204IRHBR multi channel audio chip (Ultra Low Power Stereo Audio Codec, as TI calls it). That's voltage, not power, relative to full scale.
In reality, the input signal isn't full scale, it's more like 0.1 full scale or 0.05 full scale, so the uncertainty is about 0.1%
The reflection coefficient is calculated as the algebraic combination of two of those measurements, so the uncertainty is roughly doubled (0.2%)
----o----
- thank you
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Re: New owner of nanovna-H and H4, However pondering the next step in precision
On 8/4/22 10:16 PM, Chris Gardner via groups.io wrote: Yes of course, the ohmic, or DC resistance itself in the context of the antenna impedance measurement?is a far less significant contributor than the reactance's; capacitive, and inductive. But, in terms of the device?calibration the DC components are all we use. So, I was wondering that how flawed (or not) any subsequent?analysis might be as a result of using a 50 ohm calibrator that was somewhat less or greater than 50 ohms.?I suspect not much at all.
As long as you tell the calibration algorithms the impedance of the 3 test loads, then it doesn't matter a whole lot. There are better and worse values, of course, but ultimately, it's a "solve three equations for three unknowns" kind of thing. By convention (and practical ease) the 3 standards are 0 ohms, infinite ohms, and 50 ohms. If an open is truly an open, and not some sort of capacitor, then all is good. The problem is that, particularly as the frequency gets higher, an "open" starts to look like a capacitor. It's the capacitance between the end of the center conductor and the end of the shield - imagine a dot and a ring on a PWB. There's not a lot of capacitance, but there is some. Where does it become a problem? That's hard to say without running some example cases. 1 pF at 1 GHz is -160j ohms. That's a long way from infinity (or more to the point, the reflection coefficient is 0.822-0.569j, not 1.0) And this gets back to "how accurately do you want to measure?" That 1 pF is about 35 degrees. Say you want to get to 0.1 degree. That needs zload to be at least -50,000j or, at 1 GHz, 0.032 pF. That's pretty small. My recollection is that two parallel 50 mil traces 50 mils apart would be about 0.5 pF/inch. And I'm too lazy to go hunt down the capacitance between a dot and a ring. But if we're looking at 0.141" semi rigid coax, the center conductor is 0.036" and the outer conductor is about 0.011", the dielectric is about 0.041". Let's just take that 0.041" * 0.5 pF/" and we get about 0.021 pF. So, at 1 GHz, just cutting the end squarely off 0.141 semirigid is probably a decent "open". But at 10 GHz, nope. I just happened to have a datasheet for 141 here, but one could do the same sort of calculation for a SMA connector. Or, even better, load a CAD model into a field solver (which is what mfrs do now). When you get a fancy calibration standard set, typically, there's also a set of files that come with it that give the Z for each standard vs frequency. Some VNAs let you load that in (e.g. a 3.5" floppy on an 8753C, USB stick or over the wire on newer VNAs). Be aware that you can really go down a rabbit hole on this. Once you start worrying about 0.1% kinds of uncertainty, you need to worry about all kinds of things, like mate/demate repeatability, temperatures, etc. On Friday, August 5, 2022 at 12:00:35 AM EDT, Dragan Milivojevic <d.milivojevic@...> wrote:
You are thinking in DC, switch to AC + calibration plane, fringing
capacitance etc.
On Fri, 5 Aug 2022 at 05:08, Chris Gardner via groups.io <seaman98=
[email protected]> wrote:
? Pondering a simple question relating to SMA calibration devices as in
those that are generally supplied with a newly purchased Nano VNA as an
example. Open is Open, that is obvious. The connector simply shields
the the female connector from any outside interference during calibration.
The short is obvious as well, 0 (Zero Ohms) resistive load. But, more to
the point, my biggest concern is with the supposedly 50 Ohm resistive
calibration load. I have 3 such devices from various sources, and none are
precisely 50 Ohms. My most recent purchase has a calibration sticker
enclosed in the kit indicating the 50 ohm load is 48.9 ohms. I confirmed
that value with my DVM. Would that be considered adequate, or good enough.
How significant does that difference in the ohmic resistance become in the
final sweep product. Of course assuming I am calibrating the VNA at the end
of the feed line just before the actual antenna.
? ? On Thursday, August 4, 2022 at 09:36:02 PM EDT, Donald S Brant Jr <
dsbrantjr@...> wrote:
? I got my cal kit from Dr. David Kirkby kirkbymicrowave.co.uk.? It
includes not only extensive characterization data but also optionally
verification standards which will allow you to check the quality of your
calibrations.
73, Don N2VGU
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Re: At which point do we take the value of impedance to tune an antenna?
Hi Roger,
This is an (educational) presentation, not a paper. My talks are always for radioamateurs and this formula is best known. This triggers the audience to listen before it gets more 'complicated' :-)
If you look into this presentation a few pages more, the complex impedances are explained and shown. Even the 40+j30 and SWR=2.
73
Arie PA3A
Op 4-8-2022 om 18:30 schreef Roger Need via groups.io:
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On Thu, Aug 4, 2022 at 05:32 AM, Arie Kleingeld PA3A wrote:
Lets put it simple without too many formulas. There has been a lot of
math to come to the SWR formulas but we can think about it.
Lots of things to tell about that subject. The following might be
interesting for you:
Arie,
Thank you for posting your paper. I suggest that you correct the text below to state that this formula is only true when the reactance X is 0. I have seen on many occasions people thinking that the magnitude of impedance |Z| can be used in this formula. For example if the complex impedance is 40 + j30 then |Z| =50 and the SWR is 2.0 (when the reference impedance is 50 +j0 ohms). Someone misusing the formula would think |Z|/50 = 1.0 for the SWR which is incorrect.
Roger
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Re: upgrade old version NanoVNA H vers 3.4
Hi, I have the same HW as you and update the FW regularly with the latest DiSlord versions. His project is very active and brings a lot of improvements: It supports NanoVNA-H (default) as well as -H4 (config option). You can easily switch back to your 20211230 version if you're not happy. There's no risk of bricking your device, just open it, connect the two pins of P1 and switch on -> DFU mode where you can load a new FW. Or add one wire to enter DFU mode when you hold the jog switch down during power on: /g/nanovna-users/message/10026If you want to see the 3.4 schematics just go to Hugen's place, he has also the newer HW revisions with SD card, that is supported by DiSlord's FW. HTH Martin
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Martin Glazer
Ho-Ro
Larry McElhiney
Arie Kleingeld PA3A