Hello all. Just a quick intro and a big question:

70 this year, amateur license 2E0YAH but not active at the moment due to moving from UK to Malaysia where I need to take a new exam  :(
I am (very) slowly designing and building an hf transceiver, which is why I ordered a NanoVNA a couple of days ago.
Unfortunately I only found this forum after I'd ordered a NanoVNA SAA-2, which was very cheap (USD50) so now (after reading here) I'm concerned that it may not be up to specifications.
Question:
Assuming that it powers up, and calibrates, and communicates with QT and Saver,
What simple tests could I do to give me confidence in the SAA-2?

If you attach some coax and can calibrate it at the end of the coax, at different frequencies, that is a very good start. Ideally, after calibration, with the 50 ohm load standard you get a dot on the smith chart, and flat lines on the impedance graphs.

As a basic functional test, you could "build" a rough dipole (say 20 cm legs), attaching wires at the end of the coax and verify that the impedances at and near the resonance point looks correct. (also look for the next resonance point at 3X the frequency).  Just make sure the antenna is some distance off the ground and away from metal objects.

For two-port testing, I think you could build a simple pi resistive attenuation network, although I have never done any two port-work, so I can't say much more.

I don't think this kind of testing proves the device is fully up to spec, but should give some confidence it is basically working.

Gene AE8GS

Good ideas... Thanks.

I especially like the idea of making a quick dipole
Thinking about it, it might be interesting to make two similar dipoles and transmit from one to the other using one port for each... Just for fun.

Yeah, I thought about two antennas to do a two-port test. Even at short distance there will quite a bit of attenuation, and I wasn't sure of the sensitivity of the nanoVNA. But you could have them very close together, to the point it is capacitive coupling rather than radiation.  With short (high frequency) antennas you can do all of this indoors. I have played around with things like this. I use the QT app on Windows so I have a nice big display and can watch the curves as I move things around, or walk to and fro near the antenna.

Try measuring a filter. Be aware that narrow band filters are difficult
the measure with the limited resolution of your instrument due to the wider
resolution bandwidth.

On Fri, Jan 5, 2024 at 10:40 AM <sulaiman000001@gmail.com> wrote:

> Good ideas... Thanks.
>
> I especially like the idea of making a quick dipole
> Thinking about it, it might be interesting to make two similar dipoles and
> transmit from one to the other using one port for each... Just for fun.
>
>
>

Yes. And you can easily see polarization effects by rotating one.
If you want to get fancy, you can make a circularly polarized antenna and show that the sense flips when reflected.