Topics

NanoVNA V2

hwalker
 

I gleaned the following information from one of the other nanoVNA user groups regarding nanoVNA version 2.

1. The nanoVNA will eventually reach 3GHz (and at a similar price to version 1).
2. It's going to be based on the adf4350 + si5351.
3. The 3 mixers are replaced with one higher spec mixer (ad8342) that is switched between the 3 channels.
4. A variable gain amplifier is added at baseband using one opamp and switched feedback resistors for improved dynamic range.
5. The Audio codec is removed and the stm32 built in ADC is used instead.
6. The performance should be comparable or better to V1.
7. Info about the baseband VGA design: A RFIC switch is used to switch the shunt resistor in the feedback path. The switch is basically "transparent" because the off state capacitance is in the femtofarad range (it is an RF switch) which is negligible at the IF frequency. The on state resistance is small compared to the resistors being switched in. Since the amplifier gain is mainly dictated by the feedback network, and the switch is "transparent", there is nothing other than the tempco of the physical resistors that can cause a temperature dependence. The RFIC used is the same as for the receiver RF switch, and it turns out all the maxscend switches do not have the shunt diode problem (most RF switch ICs have parasitic diodes from RF input to ground which will start to conduct at lower frequencies), so it has no theoretical lower frequency limit and can be applied at the IF frequency. This is a big improvement over using normal analog switch ICs which have capacitance in the pF range.
8. Info about linearity: The code will perform a calibration of each VGA step on boot up. Since there is no temperature dependence the calibration only needs to happen once.

A preliminary block diagram is attached. You might want to treat this as hearsay until the design appears on GitHub. The design of the original nanoVNA was released in 2016 and it took almost three years for Hugen to take the ball and run with it.

IW2FDH
 

I think that the adf4351 would be better:

Main improvements compared to the ADF4350:

* Improved 1/f in-band phase noise (5 dB)
* EVM improvement of up to 30%
* Lower PFD spurs
* Wider output range: 35 - 4400 MHz
* Small frequency/phase jumps possible without band select.

Yes, it can be used as a drop-in replacement. It is fully pin and software compatible with the ADF4350.


Andrea IW2FDH

Il 24/09/2019 04:24, hwalker ha scritto:
I gleaned the following information from one of the other nanoVNA user groups regarding nanoVNA version 2.

1. The nanoVNA will eventually reach 3GHz (and at a similar price to version 1).
2. It's going to be based on the adf4350 + si5351.
3. The 3 mixers are replaced with one higher spec mixer (ad8342) that is switched between the 3 channels.
4. A variable gain amplifier is added at baseband using one opamp and switched feedback resistors for improved dynamic range.
5. The Audio codec is removed and the stm32 built in ADC is used instead.
6. The performance should be comparable or better to V1.
7. Info about the baseband VGA design: A RFIC switch is used to switch the shunt resistor in the feedback path. The switch is basically "transparent" because the off state capacitance is in the femtofarad range (it is an RF switch) which is negligible at the IF frequency. The on state resistance is small compared to the resistors being switched in. Since the amplifier gain is mainly dictated by the feedback network, and the switch is "transparent", there is nothing other than the tempco of the physical resistors that can cause a temperature dependence. The RFIC used is the same as for the receiver RF switch, and it turns out all the maxscend switches do not have the shunt diode problem (most RF switch ICs have parasitic diodes from RF input to ground which will start to conduct at lower frequencies), so it has no theoretical lower frequency limit and can be applied at the IF frequency. This is a big improvement over using normal analog switch ICs which have capacitance in the pF range.
8. Info about linearity: The code will perform a calibration of each VGA step on boot up. Since there is no temperature dependence the calibration only needs to happen once.

A preliminary block diagram is attached. You might want to treat this as hearsay until the design appears on GitHub. The design of the original nanoVNA was released in 2016 and it took almost three years for Hugen to take the ball and run with it.

Dr. David Kirkby from Kirkby Microwave Ltd
 

On Tue, 24 Sep 2019 at 03:24, hwalker <herbwalker2476@...> wrote:

I gleaned the following information from one of the other nanoVNA user
groups regarding nanoVNA version 2.

Wow.

What after that - a NanoVNA VNA version 3 with 4 receivers supporting
unknown thru calibration?

In all seriousness, I feel the biggest problem with the NanoVNA is the size
of the screen.

Dave

--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...
https://www.kirkbymicrowave.co.uk/
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

Wolfgang Kiefer
 

Instead of the AD8342 I would suggest the type IAM81008 in the mixer stages.
It is specified up to 5 GHz and has an easily solderable package.

Wolfgang DH1AKF

Wolfgang Kiefer
 

Hello, Mr. Kirkby,
would it be possible to reduce your unnecessary lines to the essentials?
It would increase the readability of your inflated messages...

erik@...
 

If you want a really big screen you can easily build on yourself using very similar HW and some ebay modules.

Two ADF4351 generators, a resistive bridge and some AIM81001 mixers dead bug style on a PCB is all you need.

https://erikkaashoek.blogspot.com/2019/02/tuning-25ghz-cavity-filter-with-home.html

But I'm happy with 10% accuracy where others on this group may need 0.01% accuracy

pluto@...
 

I suggest the ADF5355 also but it is much more expensive than the ADF4351 (especially if you need two of them)...
https://www.analog.com/media/en/technical-documentation/data-sheets/ADF5355.pdf

About the screen, an interesting idea could be to use one of the Nextion Enhanced Series (2.4”, 2.8″, 3.2”, 3.5”, 4.3”, 5.0” and 7.0”)
https://nextion.tech/enhanced-series-introduction/

Diego

RFy
 

I saw his schematics and RF simulation files too when it was public repository.
https://groups.io/g/nanovna-users/message/2148

Seems NanoVNA2 dev hiding his works...

Dr. David Kirkby from Kirkby Microwave Ltd
 

On Tue, 24 Sep 2019 at 09:43, Wolfgang Kiefer <@DH1AKF> wrote:

Hello, Mr. Kirkby,
would it be possible to reduce your unnecessary lines to the essentials?
It would increase the readability of your inflated messages...
The name of my company, it's company number, where it is registered, and
the registered address is required under UK law.

I would have thought my messages are shorted than most, as I only quote
relevant content, and remove all irrelevant stuff.

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
https://www.kirkbymicrowave.co.uk/
Tel 01621-680100 / +44 1621-680100

Dr. David Kirkby from Kirkby Microwave Ltd
 

On Tue, 24 Sep 2019 at 11:01, <erik@...> wrote:

If you want a really big screen you can easily build on yourself using
very similar HW and some ebay modules.

Two ADF4351 generators, a resistive bridge and some AIM81001 mixers dead
bug style on a PCB is all you need.


https://erikkaashoek.blogspot.com/2019/02/tuning-25ghz-cavity-filter-with-home.html

I don't have the time to build a VNA. I wish I did, but given I have 4
VNAs here going up to 20 GHz, building another is not high on my priority
list. Perhaps if I was retired, it is something I would do.

When I briefly showed the NanoVNA at my radio club, several remarked they
could not see the screen as it was too small. I would add, the average aget
of the members in my radio club must be late 60's, with the oldest being in
their 80's, and the youngest in their 50's, so their eyesight is probably
not as good as a youngster. Unfortunately, at least in the UK, there are
not that many young hams.

But I'm happy with 10% accuracy where others on this group may need 0.01%
accuracy
I would be happy with somewhere between the two for a portable unit 😀 I
mentioned some places (NPL, METAS) and papers on measurement uncertainty in
another post since someone asked about it.

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
https://www.kirkbymicrowave.co.uk/
Tel 01621-680100 / +44 1621-680100

Pierre Martel
 

Hi to everyone,

About the nanovna2. I really dont mind the screen size. I have the first
one and find it ok. The only thing is that if used outside it is low in
lights. But the size, not a problem, I have glasses and that what they were
ordered for, helping me see smaller thing clear.

the size of the beast is what I am looking for as I can take this little
gem and brint it with me in my shirt pocket on the top of the tower. And if
I need a bigger screen I can run nanovna Saver to display the result on my
laptop screen. Heck I could even make a small 3d printed box with a
nanovan, a raspberry pi4 and a touch lcd screen and run all this out of a
few lipo battery to have a nice large display. But it would not floor me in
top of the tower up to that point.

Making it run up to a few ghz on the same screen for about the same price
would be for me the best selling point of a nanovna2

Size does matter, but not always for the same reason.


Le mar. 24 sept. 2019 à 07:45, Dr. David Kirkby from Kirkby Microwave Ltd <
drkirkby@...> a écrit :

On Tue, 24 Sep 2019 at 11:01, <erik@...> wrote:

If you want a really big screen you can easily build on yourself using
very similar HW and some ebay modules.

Two ADF4351 generators, a resistive bridge and some AIM81001 mixers dead
bug style on a PCB is all you need.


https://erikkaashoek.blogspot.com/2019/02/tuning-25ghz-cavity-filter-with-home.html

I don't have the time to build a VNA. I wish I did, but given I have 4
VNAs here going up to 20 GHz, building another is not high on my priority
list. Perhaps if I was retired, it is something I would do.

When I briefly showed the NanoVNA at my radio club, several remarked they
could not see the screen as it was too small. I would add, the average aget
of the members in my radio club must be late 60's, with the oldest being in
their 80's, and the youngest in their 50's, so their eyesight is probably
not as good as a youngster. Unfortunately, at least in the UK, there are
not that many young hams.

But I'm happy with 10% accuracy where others on this group may need 0.01%
accuracy
I would be happy with somewhere between the two for a portable unit 😀 I
mentioned some places (NPL, METAS) and papers on measurement uncertainty in
another post since someone asked about it.

--
Dr David Kirkby Ph.D C.Eng MIET
Kirkby Microwave Ltd
Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, CHELMSFORD,
Essex, CM3 6DT, United Kingdom.
Registered in England and Wales as company number 08914892
https://www.kirkbymicrowave.co.uk/
Tel 01621-680100 / +44 1621-680100



hwalker
 

Additional tidbits of information.

1. The V2 PCB is 4 layers.
2. The schematics will be posted soon, at the same time as the launch on taobao,
3. Design objectives include keeping BOM cost below $100 and compatibility with current software base.

A contact located in China indicated that the schematics are available now but only via private request. I haven't seen any info regarding screen size, but Hugen has posted in the past about prototyping with a 3.5-inch LCD. I would expect something that size or larger to keep up with the nanoVNA-F that is now being sold.

QRP RX
 

Hope they will not use integrated ADC, because it will reduce performance a lot.

David J Taylor
 

From: Dr. David Kirkby from Kirkby Microwave Ltd

The name of my company, it's company number, where it is registered, and
the registered address is required under UK law.

I would have thought my messages are shorted than most, as I only quote
relevant content, and remove all irrelevant stuff.
===========================

David,

I do like that you make an attempt to include a brief summary of the topic to which you are replying. All to often this is missing, making it more difficult for those of use reading the group via e-mail.

BTW: four lines of signature is the recognised Internet etiquette.

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

hwalker
 

qrp.ddc wrote …
Hope they will not use integrated ADC, because it will reduce performance a lot.
---------------------------------------------------------------------------------------------------------------

qrp.ddc,

That issue was raised and the reply was:

"The VGA will extend dynamic range to 100dB, plus ADC dynamic range is nowhere near being the bottleneck"

"ADC dynamic range is far from being the bottleneck. If the ADC is sampling at 1Msps and the VBW is 1kHz, a 60dB ADC dynamic range leads to a 90dB measurement dynamic range, which is more than sufficient."

"I have a prototype of a NanoVNA variant using the built in ADC on the stm32. The measurements using it are nearly identical to the audio codec variant. The reason all NanoVNAs on the market do not use this version is because of software compatibility."

Hope they the design team is correct and we don't see the degradation in performance you anticipate by removing the audio codec.

Herb

Michael
 

Well, Dr. David Kirkby from Kirkby Microwave Ltd is using this form as advertising for his business... clearly.

Michael, WT9V

On 9/24/19 11:22 AM, David J Taylor via Groups.Io wrote:
From: Dr. David Kirkby from Kirkby Microwave Ltd

The name of my company, it's company number, where it is registered, and
the registered address is required under UK law.

I would have thought my messages are shorted than most, as I only quote
relevant content, and remove all irrelevant stuff.
===========================

David,

I do like that you make an attempt to include a brief summary of the topic to which you are replying.  All to often this is missing, making it more difficult for those of use reading the group via e-mail.

BTW: four lines of signature is the recognised Internet etiquette.

73,
David GM8ARV

London Calling <punkbiscuit@...>
 

On Tue, Sep 24, 2019 at 12:27 PM, Dr. David Kirkby from Kirkby Microwave Ltd wrote:


The name of my company, it's company number, where it is registered, and
the registered address is required under UK law.
With the greatest of respect, you are not on a professional forum, or any forum that requires your company details.
The forums that you inhabit are typically hobbyist in nature.
As such there is no need to company addresses, adverts or inferred forms of self aggrandisement within your messages.
Sorry, just sayin'.

- Andy -

London Calling <punkbiscuit@...>
 

Dave K wrote:-

When I briefly showed the NanoVNA at my radio club, several remarked they
could not see the screen as it was too small. I would add, the average aget
of the members in my radio club must be late 60's, with the oldest being in
their 80's, and the youngest in their 50's, so their eyesight is probably
not as good as a youngster.
Reading glasses.
I finally decided this year to bother having some, rather than rely on "DX glasses".
Makes a world of difference.
None of us are getting younger ;-)

73 de Andy

GM4CID
 

New forum for the V2 at https://groups.io/g/nanovna-f/topics and more info from official store https://hamelec.aliexpress.com/store/5261225

Bob GM4CID

hwalker
 

GM4CID wrote ...
New forum for the V2 at https://groups.io/g/nanovna-f/topics and more info from official store https://hamelec.aliexpress.com/store/5261225
--------------------------------------------------------------------------------------------------------------------------------------

Bob,
The links you referenced are for the nanoVNA-F, it is a different beast than the nanoVNA V2. It is FreeRTOS based with an 4.3 inch IPS LCD already being offered for sale as you noted. It does not support the current nanoVNA software base, although I'm sure developers will give it a look see over time. Its firmware also is not as upgradeable as the nanoVNA.

The nanoVNA V2 will be follow the same architecture as the nanoVNA, which means that out of the box it will have access to the software base that has already been developed for the nanoVNA. It hasn't been released for retail sell so we'll have to see in what aspects, if any, it actually improves on it predecessor. I think it may eventually be renamed the nanoVNA-H or nanoVNA-H V2 to distinquish it as Hugen's product.

Herb