nanovna-users@groups.io

Re: Calibration standards - pl-259?

[email protected]

I got a set from Amazon for like $15 US. 2 so239 and 2 pl259

Re: Calibrating to a long coax? #applications #calibration #measurement

#13625

Why are the two measurements not taken in the same display format?  One
graph is in SWR one is in RL.

Tony VE3DWI.

On Tue, May 19, 2020 at 17:24 Roger Need via groups.io <sailtamarack=
[email protected]> wrote:

On Tue, May 19, 2020 at 12:48 PM, <sj@...> wrote:

I would say NO.
Sorry to say, but have worked with VNA's for 30 years and as soon as youcome
near 1/8 wavelength the measurement errors are taking over.I respectfully disagree.  My NanoVNA was calibrated from 2 to 50 MHz using
NanoVNA Saver.  Then I measured a 20M dipole at the feedpoint and saved the
results as an S1P file .  I added 55 feet of RG58 to the NanoVNA and
re-calibrated at the end of the 55 feet of coax.  Connected the antenna to
the RG58 and saved the results.  Then plotted in NanoVNA Saver using both
sweeps (one as the reference).  The results are in the pdf file below.  It
is almost a perfect overlay of the two sweep measurements so the 55 feet
was successfully calibrated out.

Roger

Re: Captured in the wild #bying #internals #buying

#13624

Thanks Roger!

Re: Captured in the wild #bying #internals #buying

#13623

Here is a photo of a Hugen 3.4.  looks the same as Jason's

Version 3.4.jpg

Re: Captured in the wild #bying #internals #buying

#13622

Close up of the other one

20200519_144444.jpg

Re: Captured in the wild #bying #internals #buying

#13621

Close up of white one.

20200519_144434.jpg

Re: Captured in the wild #bying #internals #buying

#13620

Jason,

It could be a genuine Hugen 3.4. Hugen posted that he does sell them with "sandwich" type construction instead of in a plastic case with the gift box. 

Roger

Captured in the wild #bying #internals #buying

#13619

Captured in the wild. I am aware the white one is an inferior clone but the black one appears to have a newer pcb and has a version 3.4 screened on the pcb. Is this a genuine one? It has a different board layout that brings uart p3 contacts to the edge along with p1 (dfu) and p2. 

Thanks,
Jason

20200519_144408.jpg

Re: Calibrating to a long coax? #applications #calibration #measurement

#13618

| On Tue, May 19, 2020 at 09:48 PM, <sj@...> wrote:
=
|
| I would say NO.
| Sorry to say, but have worked with VNA's for 30 years and as soon as you come
| near 1/8 wavelength the measurement errors are taking over.
| You know, in the analyzer the matrices that are multiplied together, the error
I matrice will start to influence significantly. It is very difficult to say
| that it always will not work when exceeding 1/8 (because you are closing in to
| 1/4 and the matrice in play will get 0's and infinite in some places) because
| let's consider you are clever and you measure in a narrow sweep where your
| cable length is not any close to a 1/4 wave multiplum, then it can actually
| work to some extend.
| 
| Generally if you can't evaluate when you are measuring correct, I recommend
| you to keep your calibration point as close as possible to the analyzer and
| respect you might have significant errors if your CAL point exceeding 1/8 wave
| length away from the port. 
| 
| People believing they can calibrate out 20 meter of coax at any frequency,
| does not have any idea what they are talking about.
=
+1

Re: Calibrating to a long coax? #applications #calibration #measurement

#13617

Here is a file containing the R+jX comparison from the experiment above.  Sweep at feedpoint and at end of 55 feet of RG58 overlay on top of each other.

Roger

Comparison R_jX.pdf

Re: Calibrating to a long coax? #applications #calibration #measurement

#13616

On Tue, May 19, 2020 at 12:48 PM, <sj@...> wrote:

I would say NO.
Sorry to say, but have worked with VNA's for 30 years and as soon as you come
near 1/8 wavelength the measurement errors are taking over.I respectfully disagree.  My NanoVNA was calibrated from 2 to 50 MHz using NanoVNA Saver.  Then I measured a 20M dipole at the feedpoint and saved the results as an S1P file .  I added 55 feet of RG58 to the NanoVNA and re-calibrated at the end of the 55 feet of coax.  Connected the antenna to the RG58 and saved the results.  Then plotted in NanoVNA Saver using both sweeps (one as the reference).  The results are in the pdf file below.  It is almost a perfect overlay of the two sweep measurements so the 55 feet was successfully calibrated out.

Roger

Comparison.pdf

Re: NanoVNA dealers in Europe?

#13615

We have a couple of small dealers selling them.

Re: What is the latest hardware version of NanoVna #buying

#13614

Yes, intended to put "(small screen)" after SAA ...

Show quoted text

On Tue, 19 May 2020 at 21:39, Jos Stevens <jrs@...> wrote:

Sorry the- H4 has a bigger screen and a lot of extra's in DiSlord
firmware , I think you mean the H.

Op 19-5-2020 om 17:27 schreef Dragan Milivojevic:
Way too expensive. The different versions are explained in the wiki:
/g/nanovna-users/wiki
Choice is practically between 3 versions: F (large screen), H4 latest
revision by Hugen of the original nano (small screen)
and "nanoVNA2" (S-A-A 2) that is a completely new project with better
performance but you will have to wait for it.
Safest bet is probably H4 directly from Hugen store.

On Tue, 19 May 2020 at 14:00, Andrea <sbarelman@...> wrote:
Hi to all
I would buy NanoVna but i'm little confused :) There are many version H- F....??

Any Advice ?
Thanks



or

Re: Trouble buying from China

#13613

Stevepilot;

It was being held.  Apparently, no aircraft cargo space was available until just a very few days ago.
-- 
*Mike* , K0JTA
/g/Visible-Cell-Phone
?袄冲(ツ)冲/? 

Re: Calibrating to a long coax? #applications #calibration #measurement

#13612

I would say NO.
Sorry to say, but have worked with VNA's for 30 years and as soon as you come near 1/8 wavelength the measurement errors are taking over.
You know, in the analyzer the matrices that are multiplied together, the error matrice will start to influence significantly. It is very difficult to say that it always will not work when exceeding 1/8 (because you are closing in to 1/4 and the matrice in play will get 0's and infinite in some places) because let's consider you are clever and you measure in a narrow sweep where your cable length is not any close to a 1/4 wave multiplum, then it can actually work to some extend.

Generally if you can't evaluate when you are measuring correct, I recommend you to keep your calibration point as close as possible to the analyzer and respect you might have significant errors if your CAL point exceeding 1/8 wave length away from the port. 

People believing they can calibrate out 20 meter of coax at any frequency, does not have any idea what they are talking about.

Re: What is the latest hardware version of NanoVna #buying

#13611

Sorry the- H4 has a bigger screen and a lot of extra's in DiSlord firmware , I think you mean the H.

Op 19-5-2020 om 17:27 schreef Dragan Milivojevic:

Show quoted text

Way too expensive. The different versions are explained in the wiki:
/g/nanovna-users/wiki
Choice is practically between 3 versions: F (large screen), H4 latest
revision by Hugen of the original nano (small screen)
and "nanoVNA2" (S-A-A 2) that is a completely new project with better
performance but you will have to wait for it.
Safest bet is probably H4 directly from Hugen store.

On Tue, 19 May 2020 at 14:00, Andrea <sbarelman@...> wrote:
Hi to all
I would buy NanoVna but i'm little confused :) There are many version H- F....??

Any Advice ?
Thanks



or

Re: Calibration standards - pl-259?

#13610

Calibration using SO-239 or PL-259  connectors is marginally useful at lower frequencies like the HF band because it is not an impedance controlled connector.  The link below is the only commercial set I know of and they are UHF to SMA connectors with SMA loads attached which you can buy from Amazon much cheaper. 

A review of these Array Solutions cal loads was done by someone in this group.

/g/nanovna-users/topic/71375643#11047

You can make easily make better ones and there are several YouTube and web links that tell you how.

Disclaimer:  There are a couple of topics on this group that have discussed the disadvantages of using UHF (SO-239 and PL-259) connectors with the NanoVNA.   

/g/nanovna-users/topic/71097146#10935
/g/nanovna-users/topic/71523607#11501

Roger

Re: Trouble buying from China

#13609

Question is Mike - why from 6th May to now to get to USA ? Hong Kong is the problem and has been pre Covid too :(

Calibration standards - pl-259?

#13608

Does anyone have a source for a set of calibration standards on PL-259 / 239 connectors?    Yes, I know I could “make them”, but I’d rather buy them!  ;)

-- 
Regards,
Chris

Re: What is the latest hardware version of NanoVna #buying

#13607

Way too expensive. The different versions are explained in the wiki:
/g/nanovna-users/wiki
Choice is practically between 3 versions: F (large screen), H4 latest
revision by Hugen of the original nano (small screen)
and "nanoVNA2" (S-A-A 2) that is a completely new project with better
performance but you will have to wait for it.
Safest bet is probably H4 directly from Hugen store.

Show quoted text

On Tue, 19 May 2020 at 14:00, Andrea <sbarelman@...> wrote:

Hi to all
I would buy NanoVna but i'm little confused :) There are many version H- F....??

Any Advice ?
Thanks

or

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