Re: I added copper shields and it didn't turn out as expected ...
Mike, any chance that the shield is shorting out C26 or C27?
Jeff, k6jca
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Re: I added copper shields and it didn't turn out as expected ...
That's a great case, I'm going to print one today :)
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On Mon, 21 Oct 2019, 11:04 Mike_nano, <biounit.mike@...> wrote: To the first nano I got (the one with the white 3D printed case) I added
my own carefully-made copper shields. I recently got another Nano (the one
with the orange case). It also came with no shields. However, I noticed
something - the second one has a better return loss with load for CH0 and a
better noise floor for CH1. Better than the Nano I had added shields to. I
did a lot of experimenting and calibrating and swapping of cables and
loads, and it's clear - the second one with no shields seems to behave
better in the two aspects noted before. Also, the two PCBs are identical -
no differences in design or components.
In the picture you see one of the shields removed because I wanted to see
what was going on. When I removed it, it also improved the CH1 response
(blue trace) more like the "orange" nano. I have not yet taken off the
other shield yet. I first wanted to ask the community to help me understand
this. It sure seems to me that the shields are not helping things. What am
I missing? Did I do something wrong?
.
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I added copper shields and it didn't turn out as expected ...
To the first nano I got (the one with the white 3D printed case) I added my own carefully-made copper shields. I recently got another Nano (the one with the orange case). It also came with no shields. However, I noticed something - the second one has a better return loss with load for CH0 and a better noise floor for CH1. Better than the Nano I had added shields to. I did a lot of experimenting and calibrating and swapping of cables and loads, and it's clear - the second one with no shields seems to behave better in the two aspects noted before. Also, the two PCBs are identical - no differences in design or components.
In the picture you see one of the shields removed because I wanted to see what was going on. When I removed it, it also improved the CH1 response (blue trace) more like the "orange" nano. I have not yet taken off the other shield yet. I first wanted to ask the community to help me understand this. It sure seems to me that the shields are not helping things. What am I missing? Did I do something wrong?
.
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Are some NanoVNAs shipping with the D2 voltage sensing diode installed? None of the ones I have in hand populate the diode and I did not notice it any of the online photos of the interior that I looked at. I see some levels of the firmware show a battery icon. Is that used?
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From what I can tell here, most all the NanoVNAs you order work. The first thing to watch out for when ordering lowest cost is "no battery included". Most people will need this and unless you can buy a battery for less than the delta cost and are comfortable tack soldering the battery into your nanoVNA, order one with a battery.
Another place where low cost vendors scrimp is in the calibration kit. Cheaper vendors may omit all or parts of the calibration kit. You must have some kind of calibration kit to use any VNA. The SMA calibration kit that ships standard with the nano will serve although experts on this site say it is not the best.
Low cost vendors may not package the unit appropriately for shipping. People have reported some orders were unusable.
There is debate on this site about the value of the rf shields. To my knowledge, there is no proof that the shields help performance.
The units that I have with shields also have a Qr-code on the inside cover pointing to www.nanovna.com. I think that website has fairly good documentation that is well organized. Although, at a glance, the documentatin there may assume that you have upgraded the firmware inside the nanoVNA. So, read carefully.
If you are comfortable doing these firmware upgrades, some of the devices will work to some extent up to 1.5GHz. and new functions like TDR are supported.
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Re: Authorized Distributor with 6mo Warranty?
I tried to find AURSINC but my search foo must be broken, can someone post
up a link please.
Btw that TaoBao express site is a complete black hole, I'm cancelling that
order. Nothing has happened for more than a week!
Colin
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On Mon, 21 Oct 2019, 05:42 n5kzw, <n5kzw@...> wrote: I, also, bought the AURSINC unit and am quite happy with it. I don't
regret paying a little more as at the time of purchase, they were the only
ones I saw that were shielded.
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Re: Who has used the nanoVNA wiki to find information?
#wiki
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That worked, thanks.
Mel, K6KBE
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On Sun, Oct 20, 2019 at 9:14 AM Kurt Poulsen <kurt@...> wrote: Hi Mel
Please copy from .. Until pdf and paste into your URL in a
browser. Watch out for the inserted >
Then it works
Kind regards
Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af Mel
Farrer, K6KBE
Sendt: 20. oktober 2019 18:05
Til: [email protected]
Emne: Re: [nanovna-users] Measuring ferrite beads #test-jig
Sorry the link does not open???
Mel, K6KBE
On Sun, Oct 20, 2019 at 8:54 AM Kurt Poulsen <kurt@...> wrote:
Hi Ulrich
First of all I give you the link to another document not published but
in small "circles" and it will interest you I am sure
to the Test Chamber and Measurements
above 500MHz.pdf It might be entered in the browser directly as the io
groups messages does no like my notation ?
Regarding the adaptor, to which the male centerpin is engaging, is a
straight forward threaded SMA female female adaptor with a hex nut on
either side of the top plate, with a toothed washer on the top side.
For the male centerpin to find the female center bushing I just press
inserted a small 2mm long section of the Teflon part for a male SMA
adaptor. It has a hole of 1 mm and that is enough guidance for the
male pin to home in on the female bushing. I insert an image of both
sides, and in my case it was a bulkhead adaptor used but it does not matter what you use.
No wear to consider.
Just for the fun of it I show you my mico-chamber Regarding the DC
biasing I have no experience, but I do not see a big problem in that
either. The center pin resistance is very low so not much DC blocking
required to protect the VNWA TX out. The biggest problem is to know
the impedance of the RF isolation between the DC supply and the center
pin to be high enough. I imagine a SMA T adaptor and some sort of
resistive or inductive impedance to block the low impedance of the DC
supply. The impedance of the T adaptor seen from the RF isolation is
removed by the calibration on the output side of the T-adaptor
connected to the test chamber (with no DC current applied). So the
impedance for determining the inductance of the internal ground rod
without the toroid and with toroid is straight forward measurement as
such. How many Amps the SMA adaptors can carry is a matter for studying.
In my last mail I said some nonsense about the spreadsheet, which is
used for determining the rod impedance and that only. How to subtract
the inductance for the measurement with toroid is a matter of some
mathematics I think is covered by already available material else
revert to the matter Kind regards Kurt
-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af
UlrichKraft
Sendt: 20. oktober 2019 15:25
Til: [email protected]
Emne: Re: [nanovna-users] Measuring ferrite beads #test-jig
Hello Kurt,
that is a wonderful description of what you three did a while go when
measuring the performance of ferrite materials. Very cool stuff and
because I'm just looking in exactly that topic I have a few questions
questions to your fixture. I'm still on a "beginner level" using VNA
for measuring ferrite impedances, so sorry for any stupid questiosn.
When you have inserted the ferrite bead and turning the adjustment
knob it will contact the SMA F connector at some point. What type of
SMA connector did you use? I would imagin that the inner conductor
gets damaged pretty fast after using the fixture a few times? Or is that a "special"
type of SMA with more robust inner-conductor design ?
Do you know if something similar is commercially available?
Secondly, I like to characterize the ferrits with DC-BIAS current from
0 up to 10 Amps.. That changes ferrite impedance and frequency,
depending on saturation of the material.
See
cable-emi-suppression-cores/ For relatively large ferrite cores it
might be easy just adding an additional wire through the inner
dimeter, with a DC-current. That way the
RF- and DC wires are separated.
But for smaller components like wound-beads (e.g. Fair-Rite
2961666671) I need to "inject" the DC current into the signal line of
the VNA. Do you have any experience how to do that best? What kind of
RF-filtering / DC-blocking needs to be build ? How is calibration
performed then? The additional filtering will definitely change the
overall S11 response, but I want to see only the ferrite effect on the
Impedance and not any effect of that filter. The intended frequency
range is up to 500 MHz for #61 material, but ideally for full span of nanovna up to 1 GHz.
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Re: NanoVNA-Saver 0.1.3 MAC
Ok, I rescan isn¡¯t finding anything, so I will try manual also
Thx
Dana
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On Oct 20, 2019, at 14:22, ericm@... wrote:
Hi Dana,
In OSX the nanoVNA is shown as "/dev/cu.usbmodem4001"
Normally rescan will automatically connect. You could try however to manually enter the string above
Eric
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Re: errors of "error" models
Dr. David Kirkby from Kirkby Microwave Ltd
If you do get in a position to produce a PDF that at least resembles
*¡¯ A scientific paper, with labels on the axes of graphs.
* A draft scientific paper, with labels on the axes of graphs.
* A professional report, with labels on the axes of graphs.
* An interim professional report, with labels on the axes of graphs.
please email me a copy privately. However, temporarily at least, I am going
to mute this topic, so will see no further posts on the topic unless sent
privately.
Dave.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...
Telephone 01621-680100./ +44 1621 680100
Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom
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Re: errors of "error" models
#65 : [TheLeastVNA] Code - Update 20191020 Hello, Allow us, please, to inform you that we just uploaded the new version of our /F/L/O/S/S/: Take into account, please, that with this version The Common User computes the Impedance Z of an unknown load he connects to his [NanoVNA] from the console outputs of PuTTy, as we detailed at: #64 : A further simplification of our [LeastVNA] /g/nanovna-users/message/5351and in an almost obvious analogy with what we instructed at: #59 : UPDATE : [LeastVNA] : version 20191020 /g/nanovna-users/message/5269Sincerely, gin&pez@arg 65#
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Re: errors of "error" models
GIN & PEZ;
Up to the presentation of your [LeastVNA] formula: G=(g-l)(o-s)/[(g-o)(s-l)-(g-s)(l-o)], and provided in executable form as BBC BASIC source code, I interpret as an alternative calibration algorithm.
As currently being performed in the traditional manner, it requires 3 reference measurements (SOL), which are combined mathematically with the measurements of an unknown (DUT) in order to compute accurately the reflection coefficient of the DUT FACUPOV. It there a comparison to make that will differentiate and otherwise highlight the virtues of using your algorithm?
Your 36 character long formula is misleading and imprecise as presented in, A3 of #62 : On the Most Reasonable Questions with the Most Clear Answers.
It is a compact presentation of 36 typed characters, but the variables are neither defined nor identified as complex. This may be obvious to knowledgeable readers, and those who dissect your source listing.
The NanoVNA outputs its raw results represent the uncorrected measured reflection coefficient in cartesian form. Is this a condition of your BBC BASIC implementation, or is the reader to assume the measurements can be in either rectangular or polar form?
The output of [AnyVNA] is generally understood to be S-Parameters. S11, S22,...Snn, are in fact reflection coefficients. Each of the input variables in your formula are reflection coefficients of the form S11, S22,... Snn, etc.
"No errors" implies absolute accuracy. That's going to be a tough sell.
... better yet... You might be better served if you purge the long list at the end of A3 altogether... It discloses your passion, but the content is confusing and does nothing to support or defend your claims.
My questions and comments here need not interrupt the progress of your report, but are instead offered for your consideration whilst the pdf version of your final report is being composed.
--
73
Gary, N3GO
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Re: NanoVNA-Saver 0.1.3 MAC
Hi Dana,
In OSX the nanoVNA is shown as "/dev/cu.usbmodem4001"
Normally rescan will automatically connect. You could try however to manually enter the string above
Eric
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Re: NanoVNA-Saver 0.1.3 MAC
Hmmm, Larry, so it may be a Catalina issue as it doesn¡¯t find the usb¡
I¡¯ll try it on Mojave and see if that works¡thanks for the comments.
Oh by the way what version of Python are you using??
Dana Ve3DS
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On Oct 20, 2019, at 13:41, Larry Goga <lgoga@...> wrote:
Hello Dana,
I have been running most of the recent releases of NanoVNA-Saver on my iMac under Mojave 10.14.6. I declined the upgrade to Catalina because several of my expensive software purchases would no longer work. The procedure I use is to plug the NanoVNA into my MAC, turn on the NanoVNA and then launch the Saver program V0.1.3. When the screen paints the USB port is already properly identified and I simply select "Connect to nanoVNA". It all works perfectly and has for every release of Saver that I tried starting back at about V0.0.6.
Again, this is all under Mojave, not Catalina. If you find the correct incantation for Catalina please let us all know.
Good luck,
Larry, AE5CZ
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Re: NanoVNA-Saver 0.1.3 MAC
Hello Dana,
I have been running most of the recent releases of NanoVNA-Saver on my iMac under Mojave 10.14.6. I declined the upgrade to Catalina because several of my expensive software purchases would no longer work. The procedure I use is to plug the NanoVNA into my MAC, turn on the NanoVNA and then launch the Saver program V0.1.3. When the screen paints the USB port is already properly identified and I simply select "Connect to nanoVNA". It all works perfectly and has for every release of Saver that I tried starting back at about V0.0.6.
Again, this is all under Mojave, not Catalina. If you find the correct incantation for Catalina please let us all know.
Good luck,
Larry, AE5CZ
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Re: errors of "error" models
#64 : A further simplification of our [LeastVNA]
Hello,
Allow us, please, to enhance even more more our [LeastVNA]
description, by hiding even more of its internals from The
Common User who simply does not want to know even the
slightest about "those ratios", as follows:
- - - - - - (c) gin&pez@arg (cc-by-4.0) 2019 : start - - - - - -
In our sow and facupov, the [LeastVNA] of Characteristic Zo
(usually 50 Ohm) Computes the Nominal Value for the Impedance
Z of an Unknown Connected Load to its associated [AnyVNA],
after the measurements g, s, l, o, in just two 2 steps, of a total
length of 52 characters long, as follows:
G=(g-l)(o-s)/[(g-o)(s-l)-(g-s)(l-o)] : 36 chars
Z=Zo*(1+G)/(1-G) : 16 chars
while this procedure, does not exclude The Common User, who
is interested more in his [AnyVNA] internals, to indeed proceed
further with "those ratios".
- - - end : (c) gin&pez@arg (cc-by-4.0) 2019 - - - - - - - - - -
Anyway, this fact will be included in the next Update of our
/F/L/O/S/S/ [LeastVNA] for the associated [NanoVNA] of
anyone Common User like us.
Sincerely,
gin&pez@arg
64#
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Re: errors of "error" models
Good afternoon GIN and PEZ: Briefly; Yes I have read your contiguous report @ This is much improved and helpful to me; but please understand that its falls considerably short of Dr. Kirby's stated desires and expectations. Perhaps the frustration expressed by Dr. Kirby, and shared by myself an others that may be following or attempting to follow may best be communicated by example. I have attached and renamed (for my own convenience), the first of a well written 5 part series of which a link was provided us early in this thread. This example represents the form of a well written report and I believe also represents Dr. Kirby's inference of a document entitled "Full Final Report". I should also point out that after approximately 10 minutes of searching the forum, I gave up on locating your post that provides the links to your documentation and the link to this document specifically. I finally resorted instead to providing my own downloaded copy to serve here as a prototype example of a report that an uninformed reader might expect when being presented with closing arguments of an informed third party's research. Respectfully; This is intended as a technical criticism of your communication style, and not a personal one. Our frustrations have been expressed sufficiently and clearly to this point that nonstop repetition should be unnecessary. Perhaps in your own words... The writers have been warned. My own recent post: /g/nanovna-users/message/5075... at the time of this writing... can be mostly ignored. I see the important content is being addressed. I acknowledge your response as noted and I will attempt to refrain from revisiting this topic, and hopefully limit my comments to productive or otherwise constructive ones. I will also acknowledge that it is your intent to terminate this thread with a more or less formal presentation of your work here with the NanoVNA, the introduction of your AnyVNA definition, summary of results, refinements of your algorithm(s), and ... most anticipated... your conclusions. Finally, I gratefully acknowledge your responses to my questions, guiding my understanding, and in sharing of ownership in the task of breaking through the barrier of communications. I see responses to my questions as this is being composed, so I will maintain patience and permit you time to respond. 73 Gary, N3GO -- 73 Gary, N3GO
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Know what you are buying for a test fixture. Thanks for the Coilcraft pointer. I wonder about their test jig. My "mickey mouse": * thru cal using resistor divider approximating advertised transformer ratio, - e.g. 47 + 6.2 Ohms # for ~ 9:1 considering CH1 ~ 50 Ohm loading - measure transformer as step-down with 6.2 Ohm load * hope that performance is reversible for 1:9 step-up e.g. 50 to 540 - then 390 in series with CH1, if not back-to-back stepup-stepdown
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Re: The Male Calibration Kit for AliExpress
Hi Rudi It was just my sense of humor who got me carried away. You link got me down the memory lane to the NWT4000 I also have. I wrote once a huge manual which suddenly showed up when google'd NWT4Win Kind regards Kurt -----Oprindelig meddelelse----- Fra: [email protected] < [email protected]> P? vegne af reuterr@... Sendt: 20. oktober 2019 18:10 Til: [email protected]Emne: Re: [nanovna-users] The Male Calibration Kit for AliExpress On Sun, Oct 20, 2019 at 12:02 PM, Kurt Poulsen wrote: Do not expect the NanoVNA to beat a more advanced VNA
Hello Kurt, Thank you for the detailed analysis. I do not want to tune the nanoVNA to a competitor of a HP VNA. I just want to make the best out of it with little effort, finding the weak spots and improve them, like: 73, Rudi DL5FA
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Re: Authorized Distributor with 6mo Warranty?
I, also, bought the AURSINC unit and am quite happy with it. I don't regret paying a little more as at the time of purchase, they were the only ones I saw that were shielded.
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gin&pez@arg
Oristo
Kurt Poulsen