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Filter response is very dependent on terminations. Higher load Z than filter designed load will increase coupling between filter elements, widening bandwidth and usually increases loss. Lower load Z will decrease coupling between elements and narrows filter bandwidth. Loss and ripple may decrease if the filter design was in Chebyshev region or loss could get greater if original design was Butterworth or Gaussian. The S21 input port Z is not very good so attenuator pad will help reduce the load variation. Spectrum analyzer has similar issue on its input. Any reactance in the load will detune the filter elements.

You did not mention the filter design frequency.

I have a nanoVNA, nanoVNA-F, and N1201SA units. The N1201SA is much better performance then nano's for S11 measurement. N1201SA at 1 GHz has about 50 dB dynamic range where the nano's are lucky to get 30 dB. Number on Z readout on N1201SA is much more stable and doesn't jump around like nano's.

The main difference in the N1201SA with its ADF4351 synthesizer is providing fundamental Tx signal where the nano's using the Si5351B must rely on harmonics for Tx above 300 MHz. Both use harmonic LO downmixer with the SA612 mixer.

I looked up specs for the synthesizer chips and the jitter for the Si5351B is very poor. The ADF4351(or ADF4350) is very good. The Si5351 is between 70 and 100 ps of jitter where the ADF4351 is less then 0.5 ps. That is a dramatic difference. The Tx jitter and Rx jitter are mostly independent since they are different dividers so their jitter stacks up to make things worse.

This impacts the dynamic range. The jitter at harmonics on the nano's is likely so bad that it is 'fuzzing up' the 5 KHz downconversion output to the point that it impacts the ability to measure the signal accurately.

There may be other factors such as if and how any smoothing averaging may being done or even layout/power supply noise differences. I am going to look at the Tx signals on spectrum analyzer on both units.

Measured 50 Ohm and 75 Ohm, the results were pleasing.
I'll tell you how-
The CH0 channel in Format is REAL and the CH1 channel is SMITH, the frequency is set to 50 kHz-10 MHz.
I connect the line to CH0 and at the end of the line I hook a variable carbon resistor with linearity A 470ohm. Slowly rotate the thread from maximum resistance until the Real line becomes perfectly flat. We look at the resistance readings - this is the resistance of the line. At 50 ohms, it practically lies on the center line, at the 75th it goes higher, just like in the Smith diagrams.
Meryl cables 75 and 50 ohm - an absolute coincidence in resistance.
On the screen, a piece of cable 1 meter of 75 ohm with two adapters of 50 ohms each showed a total resistance of 71.5 ohms.

A feature suggestion: Is it possible to get a delay in picoseconds directly from TDR. That would make it easier to get a starting point. I tried several values from 200ps to 50000ps and did not get a anything sensible on the Smith chart. I hoped to see a dot.
Earlier I noticed there are no impedances in polar form, that is magnitude<phase angle. There is no angle character in my keyboard.

Anyway, I use always nanovna_saver with a pc. Thank you.

Greetings, struggling with the nanovna-saver software for linux mint 19.3 mate for over a week now.I am definitely not a linux guru by any means, more like a semi dummy.
following the instructions at github.com/mihtjel/nanovna-saver I believe i have all the dependence satisfied.
When I run the pip installation python3.7 -m pip install . this the error baffling my poor head.
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-s_o_dw26/PyQt5/
Tried --upgrade pip etc.
Formatted HD, re installed Linux 19.3 Mate I have tried everything I can think of.
If anyone can point and old dummy like me in the right direction please don't be shy.
Laptop is Gateway NV53 64 bit by the way.

Thanks Jim KC2DHU

On Fri, Nov 22, 2019 at 08:22 AM, Dr. David Kirkby, Kirkby Microwave Ltd wrote:

Any male short standard would be nothing like 180 degrees. So the lack of a
properly implemented calibration routine would cause *very significant
errors* with the N connector.

Could this be resolved by using a proper (read: not cheap) N cal kit?

If N connector is only an option and not forced on all users, it seems to me that it would be acceptable to expect the user who wants it to fork for the proper cal kit, at least until the proper cal routines are developed. Since that would be only software, it can be done at a later date.

I am not sure how one is supposed to calibrate a VNA without a cal kit anyways. Simply having the option of simulating an open by not having anything connected to the instrument in the best case only solves the open issue. You still need the short and the 50 Ohm.

Hans, DJ7BA wrote: Anyone interested in more detail of (b), is invited to ask me for the derivation of (b).

Hans, because of real world losses, in a system with only one matching network, instead of a lossless system-wide conjugate match we can only have a conjugate match at a single reference plane. In most amateur systems, the matching plane is located at the Z0-match at the tuner input. My question is: Given that maximum power transfer occurs at the conjugate match reference plane, in a typical amateur radio system, where should that matching plane be located? (1) At the tuner input, (2) At the antenna feedpoint, (3) Somewhere else

Hello, Bo,
You will probably agree with me that only odd multiples of the fundamental frequency can be used for our measurements. They have amplitudes much higher than the even ones. I beg you not to create any further confusion, especially since many beginners are reading this.
I have worked on the further development of the EU1KY analyser and know what I am talking about.
73, Wolfgang, DH1AKF

I also just ordered the 4" nano using PayPal

73

Glen K4KV

Hi

In this old message I posted some pictures of the Si5351A output as the fundamental frequency approaches 300 MHz:
/g/nanovna-users/message/3285?p=,,,50,0,0,0::Created,,pll,50,2,0,34315096

A clarification of the clarification :-) The Si5351A does indeed outputs odd harmonics but also even ones and spurious too.

Bo

Thank you. I did not notice it at first. There was a discussion about Vna_saver 0.21 which didn't look very interesting at first, but there was info about this. I should have read it first

It looks like, tha we have slightly differen PCB layouts.
My PCB layout was posted in number 9245.

I have the new version as posted in 7768.
The Board doesn't work as it should. Number 8 is very bad and number 10 can be better.

Enter the delay in the calibration panel (negative number) the graphs will be updated realtime, no need for new sweep

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK

Dr. Kirkby,
I posted one day regarding safe payment with Alibaba.com
I am also not willing to enter my actual billing information!
I recently learned of I used this service to place my NanoVNA order and it worked fantastic! It does tie to your funding source but you can generate single use maximum value credit cards all day! I created a single use card that could charge me exactly once for a value up to the order total of the NanoVNA and the card dies. No further changes possible ever!

Maybe worth consideration

My only regret was waking today to find the 4” model now available for very little more money than what I just paid for a 2.8”

Good Luck Sir,
73 de Seth - W8FG

On Fri, Jan 10, 2020 at 10:03 AM, bill K7WXW wrote:

Hugen - Nice work. I am looking forward to working with the improved version.

On the alibaba page, the four inch model is the more expensive of the two listed, correct?
======================================================

Bill,
I just ordered the new 4.2 version via Paypal by directly contacting Maggie King at the Alibaba page. The higher $75 cost is for express shipment by DHS. Maggie explained that DHS shipping costs have increased. The lower $60 cost is for free shipping via post (slow boat from China).

If using Paypal, don't press the "start order" button. Start a conversation with Maggie and she will send you her Paypal email address , send her the payment via Paypal and ask her to let you know when it is received. Maggie will send the shipment to the address associated with your Paypal account.

- Herb

- Herb

Under the assumption that one of the devices, vna or sa is Bad, pad the sa or the vna with say 10 db of pad. This will force a decent match, to the tune of a 20db return loss. Then do your filter loss measurements, you better get same numbers.

As a check try the same measurement with just a pad. Try a 3 or 6 db whatever pad you may have on hand. The suspect area I believe is either source or load termination either from the vna or the sa. One of these devices is NOT providing a proper 50 ohm termination. Under the assumption that the filter is designed to be source and load terminated into 50 ohms, if these terminations are not proper, than the loss will be off between the measurement devices. The experiment with the pad may provide a clue as to what is producing this error.

To anybody who is wondering how the switch works internally, mine was broken, so I tore it apart and photographed it. Then I enhanced the photo to explain the contacts.

-Pete
K7PEB

Its in the files section of the Nanovna group under presentations.?



On Fri, 10 Jan 2020 at 4:23 PM, uni berry<uniden355@...> wrote: Hi Luc, Could you please show me the link for the english translation of
your presentation? I can not find File Section on your website.

Regards

On Mon, Jan 6, 2020 at 5:16 AM Randall Steffens II via Groups.Io <pomology=
[email protected]> wrote:

Thank you Luc, very helpful!
Randy
NC8U

On Jan 5, 2020, at 11:09 AM, Roger Need via Groups.Io <sailtamarack=

[email protected]> wrote:

?Thanks Luc for taking the time to write and translate this document.

Very well done...

Roger

On Fri, Jan? 3, 2020 at 08:31 AM, Luc ON7DQ wrote:

Hi Folks,

I finally did the translation myself, I realized it is difficult for

someone

else to get the meaning of what I wanted to tell ...

I have an open circuit on the other end of some 50cm of coaxial cable. What is the easiest way to insert some delay to tune off that cable. NanoVna_save seems to need to calibrate the Vna after every delay. That is not very good because I don't know delay exact delay yet, I wish to test different delays until I see an "open" in charts.

Yes, that’s exactly what I see