Hi Stewart
Even at 7MHz it is unlikely that you will not be seeing some stray inductance and stray capacitance, so I am more surprised, at the 0 -j50 ohms. Unless your test jig is very good and the actual capacitor is leadless you are unlikely to get exactly 0 -j50 ohms.
73
Jeff G8HUL
________________________________________
From:
[email protected] <
[email protected]> on behalf of Stewart Baker <baker@...>
Sent: 08 March 2025 14:51
To:
[email protected]Subject: [nanovna-users] Smith Chart accuracy - what am I missing ?
Hi,
I am trying to get to grips why I am not getting the same Smith Chart results with my NanoVNA as I am with my DG8SAQ VNA. I have got to the stage of trying to make everything as simple as possible. I am using the same connectors, cables and calibration standards.
To make things even simpler I am just using a quality HV mica capacitor which measures 442 pf. According to Pasan software this should be 0 -j50 ohms at 7.2MHz. When I use the DG8SAQ VNA I get milli ohms -j46 ohms, which to me is close enough.
Using the NanoVNA with an identical setup I get 11 ohms -j49 ohms. Which is pretty useless. What is going on ?
T.I.A.
Stewart G3RXQ
