The Vector Network Analyzer, VNA-2180, measures impedance (magnitude and phase) and filter transmission in the range of 5 kHz to 180 MHz.
A PC or a Windows Tablet is used to plot parameters, such as: Impedance, SWR, Return Loss (S11) and Insertion Loss (S21)
The test frequency is generated digitally.
An analog to digital converter digitizes the raw data. This avoids non-linearity associated with diode detectors, and results in very good dynamic range and linearity for accurate magnitude and phase measurements.
The RF generator can also be used as a signal source for testing receivers. The frequency is very stable and it can be calibrated with the WWV signal.
Digitized data is sent to the PC via an optically isolated USB port. Power for the VNA can be obtained from a small DC power supply or a battery. With a laptop computer, the unit is quite small and portable. Measurements can be made at ground level and translated as if they were at the antenna feedpoint by using the refer to antenna function.
The impedance at the antenna itself can be read with the VNA located in the shack at the receiving/transmitting end of the coax. The cable can be any length. The cable’s impedance and loss characteristics are determined by a simple calibration procedure and the antenna’s impedance is then plotted directly during the scan.
Numeric values can be read from the graph data using the mouse-controlled cursor.
The scan data can be saved to disk or printed to compare before and after results. It can also be imported into spreadsheet programs for further analysis.