开云体育

Hi newbie here,
I have to admit I was tempted to buy a 'nanoVNA' off Ebay without knowing about this group or the plethora of different nanoVNA's, their extended ranges and 'clones' .
So the one I have displays Gen11.TAOBAO on the splash screen and doesn't seem to have some of the menu items mentioned by other contributors on this forum.
So I guess I have a 'basic' 50k-900MHz clone?
Question....
Is the nanoVNA upgradable to extend the range to 1.5GHz as it would have been good to cover the 23cms band, or did I mess up?
If it is upgradable, can someone link me to a 'dummies guide' how to do this please?
Thanks in anticipation
Dave

Everything you always wanted to know and much more:
/g/nanovna-users/wiki

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

Hi Erik
Thanks for your swift reply.
I was aware of the wiki but haven't found reference to how you ascertain if a particular nanoVNA is (or isn't) upgradeable to higher frequency operation. (1.5GHz)
Also, I can't find a menu option to display what version of the software my nanoVNA is running. Unless the momentary 'splash' screen Gen11 is a clue?
Other contributors seem to have a CONFIG option in their menus.
Dave

Hi Dave,
First You must upgrade the hardware of Your device.
- remove R29, R30 and R31
- replace R13 by 0 Ohm
- replace R9 by 200 Ohm
- replace R24 by 91 Ohm
- replace R22, R23 by 49.9 Ohm
- replace R25 by 11 Ohm
In order to use the full frequency range (10 kHz to 1500 MHz) You must update Your Firmware.

Regards Bert

The wiki states:

All original nanoVNA and nanoVNA-H with 2.8" display can run the latest firmware. (NOT F, H4 and V2)
Using DfuSeDemo you can backup your current FW (using the "Upload" action )
and then update to a newer FW (using the Upgrade action) so you can go back if something goes wrong.

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

This HW change is optional.
A newer FW will work even without the change

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

Hi Bert thanks for the hardware information.
However .... I don't see some of the resistors mentioned on the only
schematic of the nanoVNA (12/29/16 @11:31AM) I can find.
I was interested to see which resistors needed changing before delving
inside. Is there an (earlier/later) schematic somewhere?
Dave

Hi Dave. You can find the schematics in the Wiki in the Documentation section.
regards Bert

On Mon, May 18, 2020 at 04:23 PM, <bert_winkler@...> wrote:

- remove R29, R30 and R31
- replace R13 by 0 Ohm
- replace R9 by 200 Ohm
- replace R24 by 91 Ohm
- replace R22, R23 by 49.9 Ohm
- replace R25 by 11 Ohm

Hello Bert,

Thank you very much for the hint to improve the nanoVNA hardware.
I ordered on ebay: 0603 Practical SMD/SMT ±1% Resistors Sample Book for about 20 EUR.

Now I have replaced the resistors (R22, R23= 51 Ohm) and it works great.
But you need good eyes, or a good forehead magnifying glass in my case.
See the attached screen shots from nanoVNA-saver.

73, Rudi DL5FA

Hi Dave,
I recommend the content of my web page about nanoVNA to a new user. You may also want to view the content of the links by clicking on the highlighted text. Yes, most people just like to get an answer to the problem they raise. If you want to make the most of the features of the device, it is worth learning the basics and you will have great pleasure in further experiments.
I wish you a successful use.

73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( ) ***

Hello Bert,

There is a schematic from the H4 design version 4.2.1 from 2020-02-13 which is the last version, see:

Unfortunately in the schematic the printed year is 2019, but it is from 2020.

Then the replace list is (SMD size 0603):
- remove R29, R30 and R31
- replace R13 by 0 Ohm
- replace R9 by 200 Ohm
- replace R24 by 56 Ohm
- replace R22, R23 by 51 Ohm
- replace R25 by 51 Ohm
- add a 100 nF capacitor parallel to C40, C42, C44 (SMD 0603)

Additional calibration with the software nanoVNA-saver (version 2.2) with 4 segments (404 points) and average of 4 will bring a few dB better values,
if you calibrate from 50 KHz to 1300 MHz (especially for THROUGH).

73, Rudi DL5FA

Hello Rudi,

In hugen79 H4 schematic there ara two versions of the RX input bridge.
From version 4.2
R24 - 91 Ohm
R22, R23 - 51 Ohm
R25 - 11 Ohm
From version 4.2.1
R24 - 56 Ohm
R22, R23 - 240 Ohm
R25 - 49.9 Ohm
In my NanoVNA i use
R24 - 56 Ohm
R22, R23 - 49.9 Ohm
R25 - 11 Ohm
I also tested R22, R23 - 51 Ohm - does not make big difference.
The firmware i use is version 0.9.3.3 beta FAT16/FAT32 SD card by DiSlord. This combination of hardware and firmware gives good results up to 1.5 GHz.
The S11 up to 1.5 GHz is better than 50 dB.
The S21 up to 1.5 GHz is better than 60 dB.

Best regards
Bert

Hello Rudi,

Sorry, in my NanoVNA R24 - 91 Ohm.

Bert

On Fri, Jun 19, 2020 at 10:56 AM, <bert_winkler@...> wrote:

The firmware i use is version 0.9.3.3 beta FAT16/FAT32 SD card by DiSlord.
This combination of hardware and firmware gives good results up to 1.5 GHz.
The S11 up to 1.5 GHz is better than 50 dB.
The S21 up to 1.5 GHz is better than 60 dB.

Hello Bert,
I am using the same firmware version 0.9.3.3.
Congratulation about the good hardware you have.
Mine is not so good.

If you want to show your screenshot in the forum, it is better to convert .BMP to either .jpg or .png format.
See attached screenshot Bert_50D35603.png
73, Rudi DL5FA

Hello Rudi,

The performance of my device was initially very poor. It was one of the early "bad clones" without shields.
The S11 at 900 MHz was in the range of -30 dB, S21 -40 dB.
So i made some modifications.
I added two shields to the RF parts (0.5 mm brass sheet) and a 68 uF / 10 V tantalum capacitor from the 5 V trace to ground (near the TCXO).
I also added 3 100 nF caps to C40, C42 and C44.
Before soldering the shields to the PCB i modified the TX and RX bridges as mentioned above.
Last i soldered C38 - 4.7 uF and TF1 - the SD card holder (below the LIPO pack, unpopulated on my PCB).
I replaced the LIPO by a 2100 mAh (Samsung).
The screenshot You saw are the results of theese modifications when connecting two good SMA 50 Ohm terminators (Teleg?rtner) to the two ports.

Best regards
Bert