Connection requirements, measurement controls and data handling.
RF Lab communicates through a USB CDC virtual COM port using the NanoVNA text console
(ch>). It sends info, scan,
frequencies, data 0, data 1 and
cal off. It does not implement the OwOComm binary register protocol or SCPI
for VNA measurements. Firmware must accept these commands and return the expected text format.
| Model family | Status in RF Lab |
|---|---|
NanoVNA-F series with NanoVNA-F_V2 firmware (project's NanoVNA-F3) | Measured with real hardware; 11–201 points per scan on the tested unit. |
| NanoVNA classic; NanoVNA-H / H4; NanoVNA-F / F V2 / F V3; LiteVNA 62 / 64 | Text-console families listed in the project's compatibility notes. Other models and firmware versions have not been validated here; the required command and response format must match. |
| OwOComm NanoVNA V2 (SAA2 / SAA2N), V2 Plus / Plus4, V3 | Not supported: these use a different binary protocol. |
| Siglent SSA3032X + tracking generator | Not available in the current GUI. |
NanoVNA-F V2 is not NanoVNA V2. The former is in the text-console family; the latter is in the binary-protocol family. On an untested text-console model, select a valid point count and frequency range for its firmware. RF Lab does not automatically determine every device limit.
Enter the COM port assigned by Windows and press Connect. The
Auto button probes available COM ports using info; an identification
response alone does not prove that all sweep commands will work. Press Demo
to use synthetic data without hardware.
The ordinary Demo sweep is an ideal series RLC circuit between two 50 Ω ports. S11 and S21 are calculated from the same impedance. Its resonance is placed near the center of the selected sweep; the circuit values change when the overall sweep range changes. Demo has no measurement noise or instrument errors. The separate 10 m cable example is intended for TDR and uses a different model.
Set a Start/Stop frequency and point count, and press Single.
One scan command captures S11 and S21 for every point at once - you never
re-measure just to switch what you're looking at.
The tested NanoVNA-F firmware caps a single scan at 201 points. Raise Segments above 1 (up to 16) to split your Start/Stop range into that many separate scans and combine them into one trace. The device's own point-count and frequency limits still apply to each scan; other firmware can have different limits.
Raise Averages to repeat each segment's sweep that many times and average the result, trading speed for a cleaner trace on a noisy connection or DUT.
The VIEW tile grid switches how the same captured sweep is drawn - none of these re-measure:
Press Start Calibration to begin the 4-step wizard: connect an OPEN standard (or leave the port unconnected) and press Measure OPEN; connect a SHORT standard and press Measure SHORT; connect a 50 Ω LOAD and press Measure LOAD; then optionally connect a THRU between the two ports and press Measure THRU for an accurate S21, or Skip if you only need S11/Return Loss/SWR/Smith. RF Lab computes the correction itself from these four measurements and stores them locally. The button for the current Measure step is highlighted throughout the wizard. While a standard is being read, a progress card names the standard and shows that the NanoVNA is still working; the next step appears when reading ends. If SHORT or LOAD looks like a previously measured standard, or THRU transmits about as little as the open ports, the wizard shows a warning and stays on that step. Check the connection and press Measure again. These comparisons catch clear setup mistakes; they cannot certify the quality of a calibration standard or every frequency point.
Before calibrating, optionally enter a setup name. RF Lab keeps each completed calibration in the Saved calibrations list with its time, frequency range, point count and S11/S21 type. After a restart or disconnect, saved calibrations remain inactive. With the same VNA and unchanged cable/adapter setup, set the original Start/Stop frequencies and point count with one segment, then select the matching calibration. Selection applies it immediately. Clear Use calibration to show and acquire raw data without erasing the profile; checking it again reapplies the selected calibration. Changing the selection or checkbox also recalculates the current sweep without measuring again. If the physical reference plane changed, run the calibration wizard again. Delete selected asks for confirmation before permanently removing that profile, even while disconnected. The next saved profile is selected automatically (or the previous one if the deleted profile was last).
Enter a value in Port Extension [ns] to compensate for a fixed length of cable between the calibration reference plane and your actual DUT - it corrects S11 and S21 by the extra electrical delay before each new sweep is drawn. Changing it takes effect on the next sweep, the same as calibration itself.
A new sweep normally fits the chart automatically. After zooming or using Hold scale, press Fit to data above the chart to reset that chart's zoom. The button in the separate chart window fits that window only. A fixed SWR range remains fixed; select Auto in the SWR range control to include all finite SWR values.
Click Save in the MEMORY panel to freeze the current sweep as an overlay trace - each trace gets its own color, and saving again with nothing changed since the last save is a no-op. Rename a trace in place; the new name takes effect as soon as you press Enter or click away from the edit field. Mark one trace as the reference to draw it thicker/emphasized than the rest.
Load Touchstone... reads a standard .s1p/.s2p file
(as produced by NanoVNA Saver or any other VNA tool) and adds it to your memory traces for
comparison. A .s1p file only carries S11 and is excluded from transmission
views. Files referenced to an impedance other than 50 Ω are rejected.
Touchstone S11 (.s1p)... exports measured S11; use Sweep CSV for both
measured S11 and S21.
Turn on Show amateur radio bands to shade the amateur bands that fall inside your current Start/Stop range directly on the chart - bands outside the swept range are left out, so the axis always stays scoped to what you actually measured.
Click a plotted data point to add a marker. The left panel scrolls to the new marker row, including for TDR and Group Delay markers. Each marker gets its own color, matching between its chart glyph and its row in the MARKERS list. On the Smith view, a marker's row also shows Q, parallel-equivalent R/X, equivalent L/C, return loss and VSWR - the same detail available from the hover tooltip, without needing to hover.
The current sweep can be exported several ways from the SWEEP panel:
# comments record the data and export times,
source/correction state, frequency range, point count, averaging and segments.
Disable Include measurement info in Sweep CSV in Settings
when a CSV reader requires the column header on the first line..s1p file..md report (plus its sibling
.csv) with S21 gain/phase, S11 SWR, return loss, Smith,
impedance and phase chart blocks for
MD Visor. The charts use the
selected linear/log frequency axis, SWR range and phase unwrap setting;
the companion CSV starts with # metadata comments recording
the data timestamp, export time, source, sweep range and point count
(plus averaging and segment count for a VNA sweep). It contains all finite
derived values, including SWR values outside
the displayed range. The Smith chart uses the S11 reflection coefficient
with a fixed unit circle. For raw
S11/S21 complex data, use Sweep CSV.
Open Settings... from the title bar to switch between the
Blueprint Light and Studio Dark color themes. Your theme
choice, window position, instrument address, and last-used sweep settings are all remembered
automatically between launches - stored only on your own computer under
%LocalAppData%\RfLab, never uploaded anywhere. You still press Connect/Run
yourself on the next launch - nothing auto-connects.
F1 - open this manual in your browser.