开云体育

I just received a new nanoVNA-H that I bought from Hugen. And, man, am I impressed. I'm comparing it against clone I got from another source (which has been classified at the worst of the clones). The difference is like night an day. Hugen's came via DHL in a little over 7 days (I ordered it just before the weekend). The instrument itself was packaged in a neat storage box which was then foam wrapped and placed in an outer corrugated container. It was then sent in a DHL envelope. Arrived in fine shape with no damage.

It came with two short coax cables with SMA male connectors each end. The calibration standards and a SMA - SMD female connector. It also came with TWO usb cables, one USB-C mini (micro?) and one USB-A to USB-C mini (micro?).
Most of the clones come with only one USB cable if you get that.

Powering it on and checking the version shows that it has the latest of Hugen's code. Oh, did I say the this instrument is enclosed in a case? Yup. None of the clones seem to have one and you'll pay 12 or 13 dollars for an aftermarket case. That's a bargain right there.

It came with a memory structure map printed on glossy paper. Most of the clones come with nothing.

I might also mention that the battery diode is already installed. No need to open the case to install one like you do on most of the clones.

The only issue I might find is how to open the case if you have to put it in DFU mode to load new software. But, of course, you can select DFU mode from the CONFIG menu. If you DO have to open the case, how to do it isn't intuitive but, then,
I hope I don't have to do that; I'll cross that bridge when I come to it.

I paid $50 for the clone which came foam wrapped in an envelope and shipped via slow boat from China.

I paid $60 for Hugen's from his store (Alibaba) which came DHL in about 7 days.

Whyin'ell would anyone want to pay $50 for a beat up Ford when you can buy the Cadillac express delivered for $60?

I don't know, but I've learned my lesson.

Gonna go have fun now.

BruceN / K4TQL
--
*"To invent, you need a good imagination and a pile of junk"* -- Thomas Alva Edison (1847-1931)

You are entitled to your opinion of course. But I would like to know who you actually are? On this occasion I do not totally agree with you. I am sure that you don't reside at Bag End so who are you? How do we know that you are not a business rival?

David does make excellent cal kits and is very knowledgeable, I think his agenda is to try and stop people getting carried away with what these products we are discussing actually are. Convenient, cheap, remarkable value for money. However they are not professional pieces of equipment and have short comings. That seems to be David's agenda, he seems to put the brakes on and try to stop folklore becoming fact. That is a useful contribution in my opinion.

Obnoxious and over bearing? At times, yes!

Regards

Conrad Farlow, PA5Y

I experimented with this Lambda/8 method using the program TLD (transmission Line Details) and got within .4 ohms of the cable impedance after doing a number of different tests. TLD contains the characteristics of many kinds of cables and calculates input impedance at various frequencies/line lengths based on a user input load impedance.

TLD is a free program and is available here >>> . Highly recommended

He wasn't just banned because his criticising the connectors, he was banned also because of his obnoxious and overbearing posts.He seems to have his own agenda besides shamelessly promoting his own business.
I often wondered why he had not been banned for good long before that episode.

-Bilbo

Yes, agree.
I will re visit this and with another choke as I need one in the input, grid side of the amp.

73' Alan

Hi,

wave-theory of open transmission-line (Z_l = inf) is Z =
-jZ_line*cot(beta*len_line).
If the line has a length of the line is labda/8 this gives cot(pi/4), which
is one.

Thus we have Z = -j*ZLine | lengh_line = labda/8

And we have just the wave-impdenace of the line left in the equation.

Correct me, if I'm mistaken here please, but sounds like a clever idea :)

Best Regards,
Martin


Am Fr., 27. Dez. 2019 um 16:49 Uhr schrieb Corneliu via Groups.Io
<coralenka@...>:

On Fri, Dec 27, 2019 at 06:34 AM, <nanovnagroup@...> wrote:

….. I chose this listing as the seller seemed to have overall good feedback rating, and the unit seems to include all the accessories and the ABS housing, and everything seems to be neatly organized inside a nice case.

…..
===================================================================
The packaging and included accessories are indicative of the current hugen NanoVNA-H model. The positive feedback rating, total number of sales, and reasonable delivery time make the eBay seller seem pretty safe. I've never had a problem getting my money returned on eBay if the purchase turned out to be a scam.

About the only other consideration I can think of is hugen has made some worthwhile improvements which he has included in Version 3.4 of his PCB. If you order from his official store your NanoVNA-H will have the ver 3.4 PCB installed. If you order from eBay or elsewhere there is no guarantee which version PCB will be installed.

- Herb

Hi Hans,
Thank you vm for for sharing your method with us.
I do not know which is the explanation behind this method but I can confirm it is working very well.
I have 2 pieces of professional made high quality 50 ohm cables about 38 cm long and they both measured 50 ohms +/- 0.1 ohms.
The cables supplied with nanoVna measured 53.7 and 55.2 Ohms respectively.
Thank you very much!
Merry Christmas!
73! de YO4AUL

Hi Alan,

thank you for the info. I think it is a good thing to save the measurement
files, they are taking very little space and can be re-analyzed in the
future with various software tools.
Also can be used as reference for future measurements of the same DUT, to
see any modifications.
Actually I wanted to look at other graphs, for example S11 R and X, more
comfortable for me to see resonances.
I totally agree the choke should be measured in place.
For S11 measurement of course no shorting is needed, both ends are
connected to CH0. For GDO like measurement, shorting is needed to close the
circuit.
It would be interesting to compare S11 measurements with GDO and also with
NanoVNA in GDO mode (small coupling coil on CH0).

73 Ady

I am new to this group and this is only my second post. I am happy to have found this specific thread as I was going to order what looks like one of the latest units of the original design NanoVNA (V1?) unit on ebay (it seems an "-H" release, as I have now recently learned to recognize that last letter has a meaning). But now after following this thread and seeing that good progress is apparently being made it seems it would be a good idea to hold and wait for this newer and much improved version to get released. I am in RF engineering mainly focused on 2-way radio systems design and commissioning, and having a portable tool that does so much and that still fits in a shirt pocket instead of lugging around bulky equipment would have sounded almost like SciFi only a few years ago (HP35 ~analogy intended).

But if I still decide to go ahead and make the purchase of the other unit (after all its only $47), and as I do not wish to unintentionally detract this thread from the original subject, I started a new one to ask for comments about the unit I am considering buying on ebay to make sure it is the real deal:

/g/nanovna-users/topic/wait_for_v2_design_or_but/69286381?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,69286381

Thank you.
Alex

I am new here and this will be my first post. I have been reading some of the threads of this group, and came across the one bellow that is dealing with the release of the new V2 version of the NanoVNA.

/g/nanovna-users/topic/68761814

I was about to order one of the current models off ebay, and was wondering if I could ask for advise about the particular listing bellow being of the latest (and desirable) version (apparently "-H") as I have recently learned to make that distinction. Or should I rather be looking at some other listing? Or perhaps just hold until V2 is released.

In any case if I still decide to go ahead and make the purchase of the current unit (after all its only $47) wanted to ask if this listing is the real deal, or if I should rather be looking at some other ebay seller? Since they all look very much alike to me, I am at this point really too new to this device to be able to tell the finer differences that would distinguish the real deal from a perhaps cheap copy, and I gather most of this groups members would notice that immediately without even needing a second glance. I chose this listing as the seller seemed to have overall good feedback rating, and the unit seems to include all the accessories and the ABS housing, and everything seems to be neatly organized inside a nice case.



Due to preferences and logistics I usually favor buying off ebay and generally stay away from Amazon, unless its the only option. But any other source suggestions would be welcomed.

Thanks for any and all advise.
Alex

On Thu, Dec 26, 2019 at 08:33 AM, DJ7BA wrote:

the Lambda/8 method:

Do you have any citations for this method?

On Fri, Dec 27, 2019 at 02:42 AM, David J Taylor wrote:

You might like to post questions about the NanoVNA-F in its own group:

I'm sure the developers would appreciate your suggestion for new firmware features and extended frequency range. I expect many users would appreciate
these features!
==================================================================================

Hi David,
After Dr. Kirby was banned by the NanoVNA-F group's owner for expressing negative opinions about the connectors used on the Demo board , I try to only offer assistance to other user's on that group. This group is by users for users and freely accepts the exchange of ideas. When a group is created by a retailer, as is the NanoVNA-F group, it can tend to be less receptive to any perceived criticism of its product. Dr. Kirby was eventually re-instated after other members complained about the quick yank, but the initial response was to me un-democratic.

Hopefully the NanoVNA-F's production team will start pouring more of its resources into fulfilling its promises on the software and firmware side. We all want to see products like the NanoVNA-F become successful, but we also want to see continued after market contributions such as hugen has done with the NanoVNA-H. So far I've seen words, but not action.

Happy holidays.

- Herb

#95.5: [SOLVED] : The "Mystery" of the Identical Results Using Different VNAs

Hello,

Allow us, please, to announce that in the sequence of our three guesses in time :
"Moebius" [#95.1], "Hardware" [#95.3] , and "dB" [#95.4], the very first of them is
fulfilled : "Moebius" - the details are following.

Sincerely,

gin&pez@arg

[#95.1] : On a Sufficient Condition for Identical Measurements Using Two Different VNAs
26 December 2019 - /g/nanovna-users/message/8657

[#95.3] : On the Sufficient Conditions for Identical Measurements Using
Two Substantially Different VNAs - Our Research has been Completed
27 December 2019 - /g/nanovna-users/message/8669

[#95.4] : On the Analogy of Difference of Ratios but not of Ratios
27 December 2019 - /g/nanovna-users/message/8674

:#95.5

Maybe you can share with us some files that one can convert to .stl to 3D
print?

I like the case very much.

Cheers!


73 de Luis, CT2FZI



<>
<>

Herb,

You might like to post questions about the NanoVNA-F in its own group:

/g/nanovna-f

I'm sure the developers would appreciate your suggestion for new firmware features and extended frequency range. I expect many users would appreciate these features!

Cheers,
David
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Hi Ady.

I only did a screen capture. The measurement and cal are one port only. So I would have only S11 data available.

The main thrust of the post is you need to capture a reasonable number of data points, 10 bands for 100 kHz to 30 MHz was used. You can probably get by with much less. Perhaps 401. The series loops appear with no added short applied. The choke is measured in place on the chassis. Take care with this placement if you are concerned about a problematic loop near an operating band!

A one port measurement appears sufficient.

I can capture a S data file. Might be of interest if you desire some other form of display or post processing. Although this is all very nice, I am not parting with my GDO!

Alan

Dear Alan,

thank you for sharing the measurements. I assume you used NanoVNA-saver.
Can you please share the s1p or s2p files if saved?

TNX, 73 Ady YO2NAA

Re visit this topic as I am looking at plate chokes for a tube amplifier.

I used 1010 points from 100 kHz to 30 MHz. There are 3 chokes shown here. The older National R175 shown in a prior post with its problems of 2 in band resonant conditions, a 230 uH homebrew choke for 160 - to - 40 meter. Fine but horrible beyond 15 MHz and finally a fairly nice choke at 100 uH on a ceramic core complete with a 500 pF/20 kV bypass capacitor. This choke shows a single resonance but is out of band.

It appears unnecessary to provide a short across the choke to pick up these loops if a shunt S11 measurement is used. In all cases the parallel resonate point crosses the open circuit side of the chart. A short across the choke simply rotates the reflection towards the short circuit side of the chart however the series loops stay in tact.

Alan

#95.4: On the Analogy of Difference of Ratios but not of Ratios

Hello,

- - - - - - - - - (c) gin&pez@arg (cc-by-4.0) 2019 : start - - - - - - -
This may be the result of measuring only levels and of measurements
only in dB.
- - - - - - - - - finish : (c) gin&pez@arg (cc-by-4.0) 2019 - - - - - -

Sincerely,

gin&pez@arg

:#95.4