NanoVNA-H4 – VSWR only showed how to simplify a NanoVNA to make only VSWR measurements with about the convenience of the traditional hand held scanning analyser.
This article compares measurement of a DUT similar to a common mode choke using NanoVNA and Rigexpert AA-600.
Let’s capture a measurement sweep of a small ferrite cored inductor with a response similar to what you might expect of a good common mode choke for antenna feed lines using a NanoVNA-H4.
NanoVNA-D v1.2.40 firmware
Above is a screenshot of the measurement. The measurement was also saved as a .s1p file to view in other applications.
Antscope2 v1.4.4 (2024)
Above is the file imported into the latest version of Rigexpert’s Antscope2, v1.4.4.
The Y axis is set to the maximum range (-1600 to +1600), clearly inadequate to visualise this data.
Measurement using AA-600
Above is direct measurement of the inductor using an AA-600 and Antscope2, v1.4.4. Whilst the graph is limited in Y range (-1600 to +1600), the visible part reconciles well with previous chart of the measurement made using the NanoVNA-H4, though the AA-600 has more measurement noise. The “subtract coax” facility appeared to not work properly, so the fixture compensation above is not quite spot on.
Analysers with ADC widths less than the 16 bits used by AA-600 and NanoVNA-H4 will have worse measurement noise.
Antscope v4.2.57 (2015)
Above is the file imported into the latest version of Rigexpert’s Antscope, v4.2.57 (2015), an older version from before the crippling of Antscope (Rigexpert’s Antscope takes a step backwards).
The Y axis is set to the maximum range (-5000 to +5000), not quite adequate to visualise this data, but far better than the Antscope2 graph.
Measurement using AA-600
Above is direct measurement of the inductor using an AA-600 and Antscope, v4.2.57. It reconciles well with previous chart of the measurement made using the NanoVNA-H4, though the AA-600 has more measurement noise. The “subtract coax” facility worked properly, so the fixture compensation above quite good.
Analysers with ADC widths less than the 16 bits used by AA-600 and NanoVNA-H4 will have worse measurement noise.
Questions arising
Q: Would I buy another Rigexpert analyser should this one fail, or as an upgrade (say for Bluetooth)?
A: No.
Q: Would I recommend a Rigexpert analyser to anyone?
A: No.
Q: Would I buy a different analyser should this one fail, or as an upgrade (say for Bluetooth)?
A: I do not know of a good candidate, but I have not done deep research… however, unlikely.
Q: Does that mean the day of the portable scanning analyser has passed?
A: I think the functional need remains, particularly for some type of wireless connection to a host computer, but that is only useful if the host computer application is reliable and fully supports the capability of the analyser. I do not know of product that meets that requirement.
Q: Has the inexpensive NanoVNA killed the market for a scanning analyser?
A: Probably, but the makers of scanning analysers helped that with product that did not out perform the NanoVNA, even if for a niche group of users.