开云体育

I uploaded the HW design document for the SimpleVNA to a similar named folder in the upload section of the group.
The description includes a link to github for the PC and Arduino SW
Have fun with the included pictures of my manual build
There will be some updates coming

Are file uploads getting moderated? I just checked, and the files section is completely empty.?

Try uploading again, I just changed some group permissions.

Ok now?

This time it worked. Thanks!

I added a page describing the used measurement principle.
Hope this explains why it is possible to have only minimal HW and still very good performance.
Basically the performance is made possible by the extreme linearity of the PC audio signal path and a perfect DSP IQ mixer.
All IMD in the HW mixers is eliminated and the only requirement is to stay below if 1dB compression point
All harmonics from the SI5351 are also eliminated with the measurement approach.
Calibration will remove the imperfections of the Bridge

I added one page to the already present file

Using an Arduino zero, two ADF4351 eBay modules, a 3000MHz eBay bridge and a triple receiver using the Simple VNA hardware (see file area) I was able to measure complex impedance's and tune filters till above 2.6GHz. It seems the eBay bridge stops working at around 2.8GHz. With a better bridge it should be possible to go till 4.3GHz?
The whole VNA looks like this (no shielding yet)


At the top the Zero
Below two black eBay ADF4351 modules sharing a XCO
Middle left is the green eBay 0.1-3000MHz bridge.
The middle right module is the triple receiver, each identical and consisting of a 14dB attenuator and an IAM81008?
The selection of transmission / reflections is for now with the big blue switch but this can be done with the Zero and some FET's
The grey cable takes the audio output of two IAM81008 into the PC line input.
At the bottom a DUT in the form of a 433MHz IF filter
Building the receivers on bare copper using some teflon tape to isolate components proved to be fairly simple. SMD components are mostly big 0805