The AIM 4300 antenna analyzer is the latest upgrade from the very popular AIM 4170D. It adds higher frequency range and faster graphing capability. It includes all the same features as the AIM 4170D
It measures the complex impedance (magnitude and phase) at each frequency of interest in the range of 5 kHz to 300 MHz. A PC is used to calculate all RF parameters, including R +/-jX, Magnitude and Phase, SWR, Return Loss, TL loss, and more and plot the results in an easy to read graph and interactive Smith Chart.
The test frequency is generated digitally and bandpass filters are used to reject stray signals (like broadcast stations) that are more than a few KHz from the operating frequency. A 12 bit analog to digital converter digitizes the raw data. This avoids non-linearities associated with diode detectors, and results in very good dynamic range and linearity for accurate magnitude and phase measurements.
Impedance measurements can range up to 10.000 ohms. The true phase angle is measured, so inductive or capacitive reactance can be determined without ambiguity.
The RF generator can also be used as a signal source for testing receivers. The frequency is very stable and it can be calibrated to WWV.
The digitized data is sent to the PC via the USB port. Power for the analyzer can be obtained from a small DC power supply or a battery. With a laptop computer, the unit is quite portable and it can even be mounted up on a tower at the antenna feed point if desired, with power being supplied through the USB cable.
The impedance at the antenna itself can be read with the AIM 4300 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 plotted directly during the scan.