开云体育

I looked at?Aliexpress but saw no one offering a battery. All of the descriptions seemed to be actually the same. Since there seem to be variations among those offered, it is a great help to know which have the lasted updates, before buying.?I have a bunch of excellent 18 GHz SMA male 50 ohm terminations. Each has been tested on a network analyzer. The return loss at 900 MHz will be 40 dB or greater. I can offer a very reasonable price.
k6yaz@...
Stuart K6YAZLos Angeles, California USA

The dates are slightly different when firmware is installed. I used the firmware dated June 11 (20190611). But when I checked the firmware info inside the NanoVNA it said June 12, so that is what I quoted to you. So we probably have used the same software. Sorry for the confusion.

Most of the NanoVNAs being sold have the older F/W. So there is the question, that many users face, of upgrading the F/W .

Yes, I was very lucky with the Gecko auction. It ended late at night with many of the other bidders probably asleep!

Spot on Dave, I agree. Addressing this process would provide a nice value added capability.

Alan

________________________________
From: [email protected] <[email protected]> on behalf of Dr. David Kirkby from Kirkby Microwave Ltd <drkirkby@...>
Sent: Wednesday, July 3, 2019 2:57 PM
To: nanovna-users
Subject: Re: [nanovna-users] Calibration coefficients - can one change them?

Okay, I get what you are saying now.

That problem should I guess be resolvable in the firmware, although it will
take a very careful look at the firmware to see how to resolve it. But the
problem should be resolvable.

Dave

On Wed, 3 Jul 2019 at 14:31, alan victor <avictor73@...> wrote:

I guess to make the point clear, 3.5 mm SMA standards DO NOT APPEAR as
IDEAL SHORT, OPEN on the chart. The fact that they DO on the nanoVNA SAYS
IN ITSELF... There is an issue!

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892

Tel 01621-680100 / +44 1621-680100

I just ordered the black unit with cables and battery and you're right, the Gecko unit is slightly inferior.
Have you found the source code repository for the June 12 versions of F/W? All I have are DFU files dated June 11.
You were lucky with the auction - several vendors have reserve bids that are almost the same as the normal selling price.

Regards,
Larry

Okay, I get what you are saying now.

That problem should I guess be resolvable in the firmware, although it will
take a very careful look at the firmware to see how to resolve it. But the
problem should be resolvable.

Dave

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892

Tel 01621-680100 / +44 1621-680100

Hi Larry,

You did a good job with the command list. No problems found!

Yes, there are several versions of the NanoVNA firmware. I have found that the June 12 version is the best. It fixes the problem of communication/interpolation while recalling Cal settings. Not sure how you would find commands from the binaries.

My application is running now on PC Win XP laptop. So far, I am impressed with the little NanoVNA. I have two versions, the black version (gen111.taobao.com) and the white clone (Gecko) model. Picked up the Gecko at auction for US$28. I wanted to compare the two models.

They are very similar but Taobao model seems a bit better. It has stronger type C USB connector vs micro on Gecko. Boot pads on PCB are much bigger on Taobao model. On/off switch is nicer on Taobao, with nicer feel that Gecko. Battery is larger on Taobao and the PCB looks better too, more finished. But both units seem to work. Calibration kit accessories are better on Taobao and you get a set of sma cables, thru connector and USB cable too, things not included with Gecko.

But if you have big hands/fingers you might find the units too tiny to use comfortably.

I have transferred June 12 firmware to Taobao VNA and it works well. Will do same with Gecko soon.

In next few days (or so) will be using my app to compare the impedance measuring accuracy of NanoVNA to my trusty AIM4160 impedance analyzer, which goes to 180 MHz.. As I said, this tiny little unit is amazing so far. It has already proved its worth in measuring crystals and plotting transfer functions of filters.

When measuring things like SWR for antennas in the field the handheld NanoVNA works well. Several of my antennas were found to be spot on compared to my other analyzers. But in my home lab, I like to use PC app (like NanoVNA Sharp or my own app) with the NanoVNA to measure components like coils, crystals, filters and so on.

Regards,
George

Oh I use banggood all the time. I am more of "when is it coming" does
anyone know. I ordered it on may 26th.... But its a waiting game i guess.
Just being impatient :P
Definitely need to get a batter for it thought.

Banggood, Gearbest, Tomtop and a few others are like Aliexpress and eBay (buy it now mode) - they are an umbrella of many vendors that take a % of sales.
You shouldn't have a problem - I've bought through BG many times.
Unfortunately though, sometimes it can take a couple of months of you chose free shipping.
Other times, I've received my item in 2 weeks (China to Canada) with paid shipping.
BG offers shipping insurance - buy it for a little extra and pay with PayPal so you have 2 avenues you can pursue if you need to claim a refund.
BG has warehouses in China, Europe and the US.

I had originally ordered the Gecko white unit without a battery but I just ordered a black unit with battery and cables for $10 less on Aliexpress.
Hopefully, it will take 3 weeks like the 1st one.

Cheers,
Larry

I pre-ordered my Nano-VNA from Is this a legit seller? If so does anyone have an idea on how long we will be waiting for the next batch of shipments?

I guess to make the point clear, 3.5 mm SMA standards DO NOT APPEAR as IDEAL SHORT, OPEN on the chart. The fact that they DO on the nanoVNA SAYS IN ITSELF... There is an issue!

I am quite familiar with the error. Please read my post carefully. I point this measurement observation out as this is a STRONG HINT that something is NOT correct!

In any case, I measured their "standards" independent and I found the 50 ohm load at 58.5 + j 11.5 ohm at 900 MHz.

The short and open are 412 pH and 190 fF respective.

I suspect no polynomial L or C coefficients are loaded to a table in the nanoVNA to reflect these deviations.

On Wed, 3 Jul 2019 at 13:19, alan victor <avictor73@...> wrote:

I should add, that after a calibration with their standards, the resulting
short, open and load are PERFECTLY located on the chart. Really! Wow, I
have to pray that a set of APC-7 or my sophisticated cal standards could do
so well. That said, this is a neat box and applying a little care to the
measurement and compensation for the short comings can rectify some of
these issues.

I'm afraid to say you are stepping into the error many people make. They
first calibrate with a set of standards, then see those standards look
perfect on the Smith Chart. I have hayfever at the moment, but made my
first YouTube video yesterday to show the problem.



Please ignore the sniffles I have and the fact I only used a mobile phone.


Tel 01621-680100 / +44 1621-680100

I should add, that after a calibration with their standards, the resulting short, open and load are PERFECTLY located on the chart. Really! Wow, I have to pray that a set of APC-7 or my sophisticated cal standards could do so well. That said, this is a neat box and applying a little care to the measurement and compensation for the short comings can rectify some of these issues.

Hello David,

I mentioned in a much earlier post, I have no idea what is in the firmware definition for the standards supplied with the nanoVNA. In addition, based on the physical description of the standards provided, i.e. the 50 ohm load a pair of 100 ohm chip resistors soldered in parallel, that they may not represent the state of the art! However, if there were a way to measure and characterize them as a entry to the unit, such as a classification table, that would be helpful,

I did measure their 50 ohm load after an independent 3.5 mm SOLT cal on a hp 8753 VNA and found their load standard at 900 MHz was at best 17 dB return loss. Another measurement of a second independent 50 ohm load from Weinschel on the 8753 at 900 MHz demonstrated a significantly better return loss. However, on the nanoVNA the Weinschel showed the same 17 dB return loss.

Is there an issue here? YES!

I might add, folks who use this instrument should consider obtaining SMA connector savers. It will not be long before the poor SMA connectors on the nanoVNA are tainted.

Alan

And with battery upgrade. My unit doesn't have a built in battery, so I found one, for now works... but pretend to update the connections and the battery itself, this one is a "little" big for the place (24x30x5mm) but should be 20x30x5

73's
Nuno CT1JQJ

no attachements...

On Wed, 3 Jul 2019 at 00:17, dreschel via Groups.Io <dreschel=
[email protected]> wrote:

Some photos of my NanoVNA measuring a "6.5MHz" Butterworth LP

I don’t see any attachments!

Dave, G8WRB
--
Dr. David Kirkby,

On Wed, 3 Jul 2019 at 04:04, <hugen@...> wrote:

Yes, calibration data can only be modified with electrical delay.

What exactly do you mean by that? Are you saying that the firmware has the
ability to allow one to adjust the delay of the calibration standards? If
so that’s good news. Just being able to enter a delay for the standards
will be a vast improvement over having no control whatsoever.

But someone else wrote ideal standards were assumed.

For better accuracy, I customized the shortest and most accurate

calibrations kits possible.

There’s no need to make the shortest calibration standards possible, *IF*
one can enter the delay of the standards.

*The internet is full of people claiming incorrectly the need to have the
shortest possible delays on calibration standards. * If you look at the
delays on professional calibration kits, you will find they are *longer* on
modern high-end kits than they were on obsolete kits!

The obsolete HP/Agilent 85032B type-N calibration kit had delays of



Female Short = 0.000 ps
Female Open = 0.093 ps

Those are the shortest possible delays one can make on female N.

Now if you compare those figures to the current $20,690 high-end 18 GHz
85054B kit, you will find the delays are much longer in the modern kit.



Female short = 27.990 ps
Female open = 22.905 ps

For the lower cost ($2410) 9 GHz 85033F 9 GHz kit, the delays on the female
parts are:



Female Short = 45.995 ps
Female Open = 41.170 ps

*So very approximately, for female N calibration standards:*

Obsolete 6 GHz kit - delays around 0 ps
Current $2410 9 GHz kit - delays around 43 ps
Current $20,690 18 GHz kit - delays around 24 ps

Clearly on female N parts, it’s possible to make delays close to 0, but
Keysight don’t use them.

The same general principle is true for the male N standards, but in that
case it is impossible to make a zero delay. If you check the links I gave
above, you will find the following.

*Very approximately, for male N calibration standards:*

Obsolete 6 GHz kit - delays around 17 ps
Current 9 GHz kit - delays around 43 ps
Current 18 GHz kit - delays around 60 ps

For obsolete HP 3.5 mm kits, the delays were from memory were around 17 ps,
but any of the modern kits (85033E, 85052D or 85052B) all have delays of
about 30 ps.

Naturally, the accuracy of professional

calibration parts cannot be achieved.


That statement is a bit ambiguous.

If you are saying that a high end VNA is best used with a professional
calibration kit, I would agree with you.

However, if the NanoVNA firmware always assumes idealised parts with a
delay of zero, then things would change *dramatically*. One could easily
make more suitable opens and shorts than would would have if one spent
$2410 on an 85032F. Spending even more, buying the $20,690 85054B would
give you even less suitable open and short standards.

The loads from the $20,690 kit would always be the best loads, but of
course it would be crazy to use loads that probably cost $1500 each on a
VNA costing less than $100.

Unfortunately, some clone makers do not understand the role of the

calibration kit, providing a poor quality load to act as a calibration kit,
which can result in worse measurement results.

Yes, clone makers often don’t appreciate or care what crap they turn out.
But a lot of self-proclaimed experts, writing web pages about how to make
calibration kits don’t understand what they are doing.

My own company, Kirkby Microwave, does care and we have enough knowledge to
understand most of the intricacies. I cringe at some of the stuff I see
written on the internet about VNA calibration kits.

hugen
gen111.taobao.com

Dr. David Kirkby
Kirkby Microwave Ltd.



<>

--
Dr. David Kirkby,

Yes, calibration data can only be modified with electrical delay. For better accuracy, I customized the shortest and most accurate calibrations kits possible. Naturally, the accuracy of professional calibration parts cannot be achieved. Unfortunately, some clone makers do not understand the role of the calibration kit, providing a poor quality load to act as a calibration kit, which can result in worse measurement results.

hugen
gen111.taobao.com

Hi George,
I scarfed the commands by going through main.c (and a few posts here) and there is some ambiguity on how to format a few of them as well as how executing some might affect others.

If you could verify and/or notate the command list while writing your application, I'm sure others would appreciate it.

Also, there are 3 versions of nanoVNA firmware but no one has released the sources for them (that I can find) and I'm sure there may be new commands or options not listed in the original git repository. For this I'm going to go through the binaries for more info.

Thanks
Larry