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For those who live in the UK seeking a screened NanoVNA, I have just received a black NanoVNA from eBay seller: maybeshewill (2849, 99.6% Positive Feedback). Cost ?43.50

It would appear to be correctly screened. It came with cables and a calibration pack. It appears to power-on correctly, although I haven't tested it yet. Took a while to arrive. Appreciate it is nowhere near the least expensive unit available. Also, appreciate that some feel that the screening doesn't matter.

Best regards, Andrew, G1RVD

If calibrated for amplitude at spot frequencies using nanoVNA,
then could some SDR (e.g. SDRplay has Android API) be useful for spectrum analyses?

What amplitude (dB) and phase (degrees) resolution are credible for nanoVNA?
I read e.g. 0.1dB and 1 degree for other VNAs for amateurs..

Would it be wonderful if there would be, next to the nanoVNA, a nanoSA or nano Spectrum Analyzer?

Well I decided to test what the most simple SA could look like, just good enough to test the harmonics level of your signals till 400MHz and some other, not too complex, measurements.
According to my estimate the BOM of the nanoSA on the photo would be around 12$
Main components are two SI4432 modules, one in RX mode at 443MHz using the RSSI as log detector, one as +20dBm LO for the mixer (443MHz - 886MHz), a 443mHz SAW filter as first IF filter, a Double balanced diode mixer and an arduino zero (3.3 volt) or compatible (arduino micro with 3.3v serial to USB module will also work), adding a LCD will still keep the cost below 25$ or 50$ retail.

The measurement performance is surprisingly useful.
Attached a scan of the harmonics and spurs of a SI5351 at 25MHz
And a scan of the AD9851 ast 25MHz, both connected through a 30dB attenuator

Specs:
Range 0-400MHz (0-200MHz with unmodified modules)
RBW selectable between 3kHz and 600kHz
With RWB=300kHz noise floor below -90dBm
Max signal around -5dBm
Did not yet do the IIP3 measurement but the used ADE-25MH is supposed to be +13dBm
Good enough for many measurements.
Things to further improve:
- 400MHz low pass filter at input
- remove output filter of TX module to get full 400MHz bandwidth
- Put everything in a box.

I hope someone gets inspired and puts everything on a PCB with a LCD as a small standalone SA (nanoSA)

I agree. This is a mess and hard to follow. It should have been a forum from the beginning. Suggest that since this project and others like it will continue into the future, that a forum should be started and all messages (if possible) be moved there. Do this ASAP.

This is my opinion.

Hi First test with the lab card. I'm a little worried about the contacts on the lab card

Something that I have never fully understood is that S21 is supposed to be
measured using a "matched load".

Many VNA receiver ports do NOT precisely match 50 Ohms;
inserting a precision attenuator before CH1 improves matching.

Isn't the "matched load" of a VNA equal to 50 ohms?

nanoVNA bridge and ICs are nominally designed for 50 Ohms;
I don't find a nanoVNA specification for CH1 return.

Are we to assume that 50 ohms is the only possible "matched load"?
Or can a VNA be calibrated for any value of "matched load"?

Software can "calibrate" for other loads,
but e.g. S11 sensitivity is not improved.

For two-port measurements without precision attenuator at CH1,
nanoVNA firmware does NOT compensate S11 for CH1 mismatch (see attached).
Consequently, S11 measurement for 2-port DUT
is ideally terminated by precision load or equivalent, rather than CH1, and
use only S21 measurements for DUT terminated by CH1
while appreciating that S21 are somewhat impacted by CH1 mismatch.

Warren Allgyer's 1-3000 MHz RF bridge method compensates CH1 return..
/g/nanovna-users/message/2484

On Mon, Oct 7, 2019 at 05:36 PM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:

Are there any *firmware* releases that have support for *proper*
calibration kits? By that I minimum of

* offset delay of the open
* offset delay of the short.
* C0 of the open

Did you mean that user will be able to enter offset delay for open, short and load and specify C0 for the open?

I can try to add it at least for C0. Regarding to the delay offset, I'm not sure on how to apply it to the calibration terms.

Is it correct to apply electronic delay before error term calculations?

Hi Dave

Re hashtags:

You can use whichever you prefer, i.e. email client program or web interface.

A post can have more than one hashtag.

Subscribers can mute a a certain hashtag if they prefer, e.g. because it is irrelevant.

Bo

On Tue, 8 Oct 2019 at 10:08, Bo, OZ2M <groups.io@...> wrote:

Hi

I all for using hashtags. A group on groups.io can be set to require
hashtags and also that only the owner and moderators can create hashtags.
The latter might be a good idea too.

Does that mean that users would need to use the groups.io website, and be
unable to post from an email client? If so, I would stop posting anything.

I fully agree that the traffic is too high. I wrote last month that this
group had more posts than any other I would have to start muting topics.

The Keysight VNA forums are nowhere near as active as this one, but they
have five subgroups

* General Use
* Applications
* Programming and remote control
* Calibration and Error Correction.
* Handheld Instruments


Obviously such subgroups would not be appropriate here - in particular
“Handheld Instruments”.

*I have no experience of groups.io <> subgroups*, but if
subgroups were a suitable way forward, I would suggest the following, based
on my experience of the Keysight VNA group and here.



*1) Beginners* I suggest this because I believe any new owners, especially
if they have never used a VNA before, who are going to get overwhelmed by
discussion of firmware changes, NanoVNA-Saver, the mathematics of
measurement uncertainties etc.

*2) Firmware development*

*3 Programming and remote control* - for software like NanoVNA-Sharp,

*4) Advanced applications* *& technical discussion *

*5) Calibration and error correction*

*6) General Use*.

Dave
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

thanks, this is all helpful. I found through a few different evaluations of the info I was getting, a range of R, that got me in the ballpark and made tuning the circuit fairly painless (if anyone considers desoldering and resoldering 0603 smt's painless). I'm hoping to measure the total Q of the network and antenna now, using the nano, is this basically done setting logmag display on channel 1, hooking up the matched network and antenna to channel 1, and putting a small coil on channel 2, putting them in proximity and measuring the falloff rate of channel 1 from the maximum amplitude?

I just released 0.1.1:



This version adds a first version of an analysis mode, which will analyse
low-pass, high-pass and band-pass filters for you. Give it a go, and tell
me how it fails ;-)

Also added is easy sweeping of bands (selectable within Sweep settings),
unwrapping of the phase chart, floating point min/max values for data for
charts, and deleting of calibration standard sets.

The release also includes a display option allowing you to select whether
Return Loss should be presented as a positive or negative value.

This version should behave better with multi-segment sweeps using NanoVNA
firmware 0.2.2. It's slower, though. I suggest users upgrade to 0.2.3, and
the next version of NanoVNA-Saver will start using the "scan" command added
in edy555's firmware to get around these issues.

This version should work with NanoVNA-F, though I have had no way to test
it - I look forward to hearing if it does.

I thank the testers who have been quick, found several bugs that I have
managed to fix, and who have come up with a whole list of items that got
added to the backlog!

As ever, I look forward to hearing your feedback! Please be gentle ;-)

Enjoy,
--
Rune / 5Q5R

For those who may be don't know, my software mod can be found here:

Hi,

this is not really new, but very helpful for 80m DX:

I had a W3DZZ that had a sharp response in the center of the (EU) 80m Band.
But CW or SSB DX is at the band ends.

Before (blue curve) the W3 was only doing a reasonabl job near resonance at
center.

Thanks to SimSmith freeware I could determine the optimum coax length and
use an appropriate L and C to flatten the frequency response.

See both, before (measured with my Rigexpert AA-600) and after (measuered
with NanoVNA)
frequency sweep responses as displayed by NanoVNA-saver's:




(I wish, NanoVNA saver could show SWR circles, too.)

For more info on broadbanding (including the Smith Chart basics) see this
excellent Link:



enjoy,

73, Hans
DJ7BA



--
Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.

Hi

I all for using hashtags. A group on groups.io can be set to require hashtags and also that only the owner and moderators can create hashtags. The latter might be a good idea too.

/g/nanovna-users/settings | Message Policies | Hashtags Required and Hashtag Permissions (only visible to owner)

Unlike accounts on e.g. Yahoo! Groups, an account on groups.io can have a group specific profile:

/g/nanovna-users/editprofile

and also two different group specific standard signatures (web posting and email posting):

/g/nanovna-users/editsub

Thus no need to have same group profile on your NanoVNA account and your local Swinger Club.

Bo

That's why I configure 'no-email'. Now I am using web browser only.
But... I can not BLOCK anymore self promoting 9+ line signature salesman. sigh...

When there's too much traffic from a group I switch to a daily digest. I then only read the messages from the groups.io website. Although I may miss something useful I don't have to wade through unwanted traffic in my email inbox.

--
73
Richard
G4TGJ

From: Roy Appleton

So that's what's going on. From the email readers point of view it's a mess!

Roy
WA0YMH
========================================

100% agreed, Roy! An unnecessary duplication, and a proliferation of e-mails.

Dave: there is a group setting which disables users from editing their messages and would prevent these unwanted multiple e-mails.

73,
David GM8ARV
--
SatSignal Software - Quality software for you
Web:
Email: david-taylor@...
Twitter: @gm8arv

Thank you John for answering/addressing my question. Tried an air cored inductor, and the S21 attenuation was increasing almost linearly with frequency 1-300 MHz. So, as you said the the ferrite core is the reason behind this flat loss response.
I guess this means that I can use this inductor around FT23-43 effectively as an RF choke near Vcc with a bypass cap to ground for this frequency range which was the reason behind this test.

Looks like it to me! Just double the price but you can get them in 3 days
not 3 or 4 weeks! ?

Roy
WA0YMH