FAQ

Connect the DUT to the NanoVNA-F3's port, run the OSL calibration wizard first for an accurate result, set Start/Stop [Hz] to bracket the frequency range you care about, and press Single. Switch to S11/SWR or Return Loss - both come from the same S11 sweep, just plotted differently.

Connect the DUT between the NanoVNA-F3's two ports, run a THRU calibration step (part of the OSL wizard) for an accurate reading, set your frequency range, and press Single. The S21 view plots gain (dB) against frequency; S21 Phase and Group Delay give you the phase side of the same sweep without measuring again.

Any S11 sweep already carries impedance - switch to Smith for the full chart (constant-resistance circles, constant-reactance arcs) or R+jX for resistance/reactance plotted straight against frequency. Click a point on the Smith chart, or a marker anywhere, to see Q, parallel-equivalent R/X, equivalent inductance/capacitance, return loss and VSWR for that exact frequency in the MARKERS list.

Connect the cable under test to the NanoVNA-F3's S11 port, run a sweep across a wide enough range to resolve the fault, switch to TDR, and set the cable's own Velocity Factor from its datasheet. The band-pass impulse locates prominent reflections; the low-pass step needs a harmonic frequency grid and estimates the unmeasured DC value. A prominent reflection is not automatically the cable end. Check the result against a known cable before relying on its distance or impedance.

Raise Segments (up to 16) in the SWEEP panel. RF Lab splits your Start/Stop range into that many back-to-back sweeps at the device's own point cap each, and stitches the results into one continuous, evenly-spaced trace - no duplicate or missing frequency at the segment boundaries.

Every connector, adapter, and length of cable between the NanoVNA-F3's ports and your DUT has its own small response that isn't zero, especially as frequency rises. The OSL (Open/Short/Load) wizard measures three known reference standards and computes a correction from them on the PC side - RF Lab keeps its own correction math, rather than relying on the device's internal calibration state.

Completed calibrations are saved as separate profiles between sessions, but none is applied automatically after reconnecting. Select and explicitly activate a profile only with the same VNA and unchanged cables, adapters and reference plane; the saved frequency range and point count must match the next unsegmented sweep.

It compensates for a fixed length of cable between your calibration reference plane and the actual DUT, expressed as an electrical delay in nanoseconds - S11 is corrected for the round trip, S21 for the one-way path. Use it when you calibrate at the end of a cable but can't move the reference plane there physically. Like calibration itself, a new value takes effect on the next sweep, not retroactively.

Only the bands that overlap your current Start/Stop sweep range - a band entirely outside what you're viewing is left out, so turning the overlay on never distorts or stretches the frequency axis to include a band you're not even looking at.

Yes - Load Touchstone... reads a standard .s1p/.s2p file (as produced by NanoVNA Saver or similar tools) into a memory trace for comparison. A .s1p file only contains S11 and is excluded from transmission views. Files referenced to an impedance other than 50 Ω are rejected to avoid incorrect impedance readouts. Export writes measured S11 as .s1p; Sweep CSV contains both measured S11 and S21.

Yes - press Demo in the ribbon instead of entering a COM port. It drives every view mode from a simulated sweep. The ordinary sweep uses one ideal series RLC circuit between two 50 Ω ports to calculate both S11 and S21. Demo data are not measurements.

RF Lab uses the NanoVNA text console over USB CDC/COM, including scan, frequencies and data 0/1. Real-hardware testing in this project covers a NanoVNA-F series unit reporting NanoVNA-F_V2 firmware. The NanoVNA classic, H/H4, F/F V2/F V3 and LiteVNA 62/64 are text-console model families, but their individual firmware versions have not all been tested with RF Lab. See the compatibility table.

No. The OwOComm NanoVNA V2 (SAA2/SAA2N), V2 Plus/Plus4 and V3 use a different binary protocol and are not supported. NanoVNA-F V2 belongs to the text-console family. The similar names do not indicate protocol compatibility.

Everything - sweep results, calibration, memory traces, preferences - stays on your own computer, under %LocalAppData%\RfLab, and wherever you choose to export files. RF Lab has no server, no account, and no telemetry - see the full privacy policy.