Saving Calibrations

The NanoVNA-F V3 provides 13 save slots (numbered 0 through 12) for storing calibration data. Each slot preserves the full calibration state — including the frequency range, sweep points, and all correction coefficients — so you can instantly switch between calibrations for different measurement setups.

Why save calibrations?

Calibration takes a few minutes each time. If you regularly measure at the same frequency ranges with the same cables, saving those calibrations lets you power on and start measuring immediately.

Common scenarios for multiple saved calibrations:

• Slot 0: HF range (1 MHz - 30 MHz) for amateur radio HF antennas
• Slot 1: VHF range (100 MHz - 200 MHz) for 2 m antennas
• Slot 2: UHF range (400 MHz - 500 MHz) for 70 cm antennas
• Slot 3: Wide span (1 MHz - 4.4 GHz) for general scanning
• Slot 4: Cable testing setup with specific adapters

The RECALL and SAVE menus

Both menus are accessed from the CAL menu. They each present a list of numbered slots.

Saving

After completing a calibration (OPEN, SHORT, LOAD, THROUGH, then DONE):

1. Navigate to CAL on the main menu.
2. Tap SAVE.
3. Select a slot number (SAVE 0 through SAVE 12).
4. The calibration data is written to non-volatile storage immediately. It persists across power cycles.

Caution

Saving to a slot overwrites whatever was previously stored there. There is no confirmation prompt. If you have a calibration in slot 3 that you want to keep, choose a different slot.

Recalling

To load a previously saved calibration:

1. Navigate to CAL on the main menu.
2. Tap RECALL.
3. Select the slot number (RECALL 0 through RECALL 12).
4. The calibration is loaded and correction is applied. The frequency range and sweep points change to match what was saved.

Note

Recalling a calibration changes the frequency range to match the saved state. If you then change the frequency range manually, the calibration data will be interpolated (indicated by an asterisk * in the status) rather than exactly matching.

Slot 0: The power-on default

Slot 0 has special behavior: it is automatically loaded when the NanoVNA-F V3 powers on. This makes it the natural choice for your most frequently used calibration setup.

If slot 0 is empty or has never been written, the instrument powers on without any calibration active.

Tip

Keep your most general-purpose calibration in slot 0. If you primarily work with VHF antennas, save your VHF calibration there. You can always recall a different slot when needed.

Calibration status indicators

The calibration status area in the upper portion of the screen tells you exactly what state the instrument is in. Here is a complete reference:

Indicator	Meaning
(blank)	No calibration applied. Measurements are uncorrected.
O	Open standard has been measured (but calibration not yet completed)
S	Short standard has been measured
L	Load standard has been measured
T	Through standard has been measured
OS	Open and Short measured (partial calibration in progress)
OSL	Open, Short, and Load measured (one-port cal ready)
OSLT	All four standards measured (full two-port cal ready)
C	Correction is active (calibration applied to live measurements)
C0 - C12	Correction active from the indicated save slot
*	Calibration data is being interpolated because the current frequency range differs from the calibration range
c	Calibration active but with reduced accuracy

Reading compound status strings

A typical status string like OSLT C3 means:

• OSLT — all four standards were applied during this calibration
• C3 — the correction data was recalled from (or saved to) slot 3

If you see OSLT C3*, the asterisk tells you the current sweep range does not exactly match what was calibrated in slot 3. The instrument is interpolating, which is usually fine for moderate range changes but degrades accuracy for large shifts.

Managing your save slots

Since there is no way to label save slots on the device itself, consider keeping a simple log of what each slot contains:

Slot	Frequency Range	Setup Notes
0	1 MHz - 30 MHz	HF, direct connect, no cable
1	130 MHz - 160 MHz	2 m band, with 30 cm RG405 cable
2	420 MHz - 450 MHz	70 cm band, with 30 cm RG405 cable
3	1 MHz - 4400 MHz	Full span, direct connect
4	…	…

Tip

You can also use the CONFIG > USER DEFINED feature to display a short text string on screen. Some operators use this to note which calibration slot is currently active and what it covers.

Transferring calibrations to PC software

When connected to NanoVNA-Saver or similar PC software via USB, the software can read and store calibration data independently. This is useful for archiving calibrations or applying them when controlling the VNA from a computer. See USB Connection for setup details.

Next steps

• Full Calibration — the complete calibration procedure
• Port Extension — compensate for additional cable length
• Calibration Status Codes — full reference for all status indicators