# Help on Calibration

There are four diagram areas on this dialog. Depending of the selected mode and analyzer type, one or more diagram areas are enabled for usage.

For every visible diagram, a measurement must be made to create a valid main calibration dataset. When all the required calibration data has been created, the SAVE button gets enabled and the UPATE button receives a green background to indicate, that a complete main calibration dataset is now recorded.

The created main calibration dataset can now be used in the application by simply pressing the UPDATE button, which will also close the dialog. If one or more curves do not match the expectations simply rerun the needed calibration by pressing the button below the diagram again.

When closing the dialog using the UPDATE button, the calibration status in the status bar is updated.

## Overscan

To get smoother scans when the measured object s resistance is near one of the calibration references (means i.e. the measured resistance is 50Ohm real which is identical with the reference value 50Ohm) an over scan feature was added.

In the calibration dialog exists an input field , where the number of scans can be entered. This number of scans is executed when the readXXX button is pressed. The calibration curve used is the arithmetic mean of all scans executed. The higher the number, the smoother the calibration data is.

### Remark

The time needed to create a i.e. 5x over scan is about 5 times the duration needed for a 1x over scan. The resulting calibration data file contains no information how many over scans where used during creation

## Scan mode

Starting with release 2.8.5d of vna/J there are two modes for the calibration.

### Mode 1

Depending on the analyzer type, the maximum scan range of the analyzer is divided into 1 or more ranges with different number of calibration steps. This results in enhanced resolution in these scan ranges.

### Mode 2

This mode uses a fixed number of calibration steps in maximum scan range of the analyzer. For some analyzer types, the number of steps can be changed in the driver info dialog.

### User-definedy

These scan ranges can be changed by the user by editing a simple text file. The driver specific text-file is created when the calibration dialog is first opened. The filename depends on the short-name of the driver. The file is located in the preset directory of vna/J. The text-file must contain lines with exactly this format:

[start-frequency]blank[stop-frequency]blank[number of steps]blank[#overscan]

- The frequency must be within the range of the driver. You can check the minimum and maximum frequency in the driver info dialog. The frequency values must be in Hertz.
- The ranges must cover the complete frequency range of the driver.
- The number of steps must be within the range of 10 and 30.000.
- The number of overscan must be between 1 and 10
- The ranges must be listed in ascending order
- The ranges must contain no gaps and no overlap

### Sample for miniVNApro

- 100000 999999 4000 1
- 1000000 9999999 4000 1
- 10000000 29999999 10000 1
- 30000000 200000000 10000 1

### Sample for miniVNA tiny

- 1000000 30999999 10000 2
- 31000000 3000000000 10000 1

### Hint

If you get stuck in using these user-defined scan ranges, simply delete the corresponding file in the preset folder of vna/J