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When using the nanoVNA at frequencies above 300MHz it switches to harmonics mode
First attached picture shows the harmonics till 1600MHz of the SI5351 output when set at 100MHz.
The 9th harmonic is at 900MHz only 34dB below the fundamental at 100MHz.
To validate the performance of the SA612 I soldered two wires to output of the REF mixer and observed the output using a balanced USB audio input
Second picture shows the 8k audio FFT when the nanoVNA is set to 1MHz. About 100dB SNR at this small audio BW.
The nanoVNA uses less points (48) in its calculations and has therefore substantial less SNR
The third picture shows the output when set to 2GHz. The SNR is reduced to something between 20 and 30dB
This 80dB signal reduction is much larger as the reduction of power in the harmonics but can probably be attributed to the mixing loss in the SA612 as it it operated way out of spec (max 500MHz)
The fourth picture shows the roughly 50dB SNR you get when you operate the nanoVNA at 2GHz from a clean 5V supply. A very welcome improvement making S21 measurements possible.
A quick calculation based on the schematic suggests the REF mixer has the highest signal levels while the TRAN mixer is 10dB lower and REFL is 20dB lower
If I have enough courage I may change the attenuators for the REFL and TRAN mixer to get more balanced power levels.

On Thu, Oct 17, 2019 at 11:45 AM, QRP RX wrote:

can anyone show the circuit and photo where this 5.1k resistor should be
installed. Is it possible to install it on NanoVNA-H pcb?

Have a look here:

You need to attach 5.1K resistors to ground from cc1 and cc2.

Scroll up the webpage to see the pins

can anyone show the circuit and photo where this 5.1k resistor should be installed. Is it possible to install it on NanoVNA-H pcb?

Martin
5:37am #5091

Martin - G8JNJ wrote: Owen is one I'd always listen to, even if personally challenged by what he has said or written. It's happened to me, I've learnt a lot in the process, and continue to respect him.

Ditto for me. After I decided to ignore the irrelevant emotional content, I learned a lot from Owen Duffy.

Some people said that you can solder anything you see, so get a magnifying glass.

"Some people" have never experienced familial palsy.

"Some people" have good depth perception

From: sala nimi: Some people said that you can solder anything you see, so get a magnifying glass.

"Some people" have never experienced familial palsy.

I have been using a fixed L and a fixed C on 3.5 and 10 MHz. Works very
well in getting a quick check of calibration.

Mel, K6KBE

<>
Virus-free.
www.avg.com
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

#52 : Update : The compact SLO formula for [AnyVNA]
-
after
/g/nanovna-users/message/5081 - 17 October 2019
/g/nanovna-users/message/5075 - 17 October 2019
by Gary O'Neil
-
@Gary O'Neil:

Dear Gary,

Thank you very much for your most valuable comments !

Allow us, please, to ask you to give us enough time to prepare
our replies.

Meanwhile, take into account, please, that you already motivated us
to attempt to write a minimal set of statements, valid more-or-less
in ANY computer language having NO internal type of COMPLEX
variables and only a REAL one, regarding :

#42 : The compact SLO formula for [AnyVNA] - 12 October 2019
/g/nanovna-users/message/4747

in order to be ready for embedding them in ANY related program
by the interested reader of- and/or contributor to- this thread of
messages.

However, during the transferring of that formula to statements,
and after we found and corrected an existing typo in it, we
finally succeeded a further compactification of it, and thus
we updated it, as follows:



that is in a super-mini form most appropriate for this
particular work : Thank you - Please, stay tuned

Best regards,

gin&pez@arg

52#

Perhaps a 500 ohms reactance would work in measuring.

Perhaps calibrating nanoVNA THRU using an RF Active Probe, e.g.

Hugen,


If I order a NanoVNA-H today will it have the 5.1k Type-C CC resistors installed?


What is the link to your Nan0VNA-H site?


If someone does not have a NanoVNA with the resistors does this workaround when connecting to a USB Type-C port:


USB Type-C to USB Type-A Male cable (supplied with NanoVNA) to Type-A Female USB Type-C cable


Mike N2MS

Hi

Perhaps the caption should have been "nanovna-saver – a premature look".

I mean it is of version 0.1.0. I took a different approach than writing a blog entry, or webpage, about it, namely to engage in the evaluation, and report my findings and suggestions to Rune. So from a kind of "aaaahhhh, no thanks" to "OK, interesting - let's see what this can become."

Indeed I had my head scratching moments too. The very first one was the NanoVNA and -Saver and the indiscriminate use of CH#, Port# and S## (My NanoVNA measures S00, and S10 instead of S11 and S21 etc.). I did a lot of wrong calibrations. Yes, the return loss, S11 (S00), reflection coefficient are not three different names for the same thing. But I am sure we will get there.

With the very best of intentions
Bo

Wow - you have a lot of time to look up all of these posts!Are you going to put all this in the application notes section of the wiki?

On Thursday, October 17, 2019, 9:40:12 a.m. GMT-4, Oristo <ormpoa@...> wrote:

> I have one of the $9.00 eBay bridges, and a noise source.

With a SDR as a detector I can do some Nano to Bridge comparisions, I hope.

Enhancing nanoVNA by an eBay 3GHz RF bridge is interesting.

Before getting nanoVNA, I considered using SDR and noise source with
eBay clone

Warren Allgyer seemingly reported comparable results
/g/nanovna-users/message/2484
using 3GHz bridge with nanoVNA vs nanoVNA alone,
which resistive bridge was analyzed by alan victor
/g/nanovna-users/message/1252

QRP RX described using nanoVNA to measure 3GHz bridge directivity
/g/nanovna-users/message/2880

Erik, PD0EK uses 3GHz bridge in his 35MHz - 3GHz breadboard VNA
/g/nanovna-users/message/2054
/g/nanovna-users/message/3422

I have one of the $9.00 eBay bridges, and a noise source.
With a SDR as a detector I can do some Nano to Bridge comparisions, I hope.

Enhancing nanoVNA by an eBay 3GHz RF bridge is interesting.

Before getting nanoVNA, I considered using SDR and noise source with
eBay clone

Warren Allgyer seemingly reported comparable results
/g/nanovna-users/message/2484
using 3GHz bridge with nanoVNA vs nanoVNA alone,
which resistive bridge was analyzed by alan victor
/g/nanovna-users/message/1252

QRP RX described using nanoVNA to measure 3GHz bridge directivity
/g/nanovna-users/message/2880

Erik, PD0EK uses 3GHz bridge in his 35MHz - 3GHz breadboard VNA
/g/nanovna-users/message/2054
/g/nanovna-users/message/3422

Hi Rune , very happy for the new improvement on the 0.1.3 of nanovna-saver.
Suggestions for the future version :

1 Save the settings of nanovna , start stop center number segments , sweep mode , when saving the calibration ,not necessary as separate file , better in the same file. Recalling calibration file , the parameters will be update automatically.

2 Have a marker over the graphic for the main parameter , as a choice instead to display all data.

Many thanks again for your effort to improve the SW that is making the nanovna a very powerfull piece of hardware.

Best regards
Maurizio IZ1MDJ

That said, there are number of useful tutorials on YouTube. Listing them
would also help new users.

Citing in messages helpful specific URLs applicable to nanoVNA (and
why) has value.

On Wed, Oct 16, 2019 at 09:22 PM, Martin wrote:

I've got some other info that may be of help, but I can't find the document at
the moment.

Hi Rune,

I still can't find my old paper notes on the subject of Cs, Cp, Ls and Lp but this Keysight document seems to be the closest to what I was looking for.

Section 1 of this document



Section A1-5 of the following is also useful and Table A1-3 in this document define the various formulae



Regards,

Martin - G8JNJ

On Thu, Oct 17, 2019 at 12:54 PM, Bilbo wrote:

why would anyone care what Mr. Duffy has to say?

Because in my experience he is usually correct in what he says, and his blog postings lead to greater understanding of various subjects, mainly due to him challenging what others may take for granted, or worse still, may be inadvertently propagating as false information.

There is a lot of misinformation on the internet, and there are very few who seem to be bothered to try and correct it when uncovered.

Owen is one I'd always listen to, even if personally challenged by what he has said or written. It's happened to me, I've learnt a lot in the process, and continue to respect him.

Regards,

Martin - G8JNJ

"NanoVNA-H V3.3" tag

A dedicated USB attachment,
stripped of display, battery, and switches
would be nicely light weight and efficient

The question is, why would anyone care what Mr. Duffy has to say?

Yes I thought that something like that would happen. If I put a tuned circuit on the collector/drain and match it to 50 ohms, it will not tell the true Hfe. Perhaps a 500 ohms reactance would work in measuring.

LM