Automatic antena measurement sation

    In this project I participated with my two colleagues Ferdinand and Thomas. Our goal was to make a functional mechanism for antenna radiation pattern measurement, driven from PC.
    According the reciprocity theorem, transmitting and receiving parameters of an antenna are the same, so because of the simplicity we made the system with reference antenna static and  measured antenna turning around its vertical axis. For the test purposes we were using directional Yagi antenna.

Mechanism:

    There were a lot of factors, we had to consider such as stability, bearing capacity, universality as for antenna holder diameter, and so on.
    Because there was no time for experimentation with new mechanisms, the simplest way to fulfill the stability and universality criteria was to use two aluminum stripes for antenna holder attachment.
    For turning the mechanism with required precision, we used worm gearing with 1:44 rotating ratio. Thanks to that, we were able to turn measured antenna with not very strong DC motor. We used a geodetic stand as base of the mechanism and connected it together with special adaptation pad. Whole system was putted inside an metal box. The motor we used was small 12 V powered DC motor with encoder for an angle control (there were jokes about it being removed from electric toothbrush). The vertical angle of antenna can be set by this motor, or manually, using simple built in mechanism and protractor.

Controlling:

    For controlling the mechanism there was a simple circuit board designed, using Arduino module. Its job is to receive PC commands and generate motor driving signals. The circuit was put inside waterproof plastic box on the side of mechanism.

PC software:

    PC software was designed in MATLAB as exe app. It is able to automatically generate signals for motor controlling circuit according to user entered parameters. It automatically connects to spectral analyzer over Prologix GPIB-ETHERNET, sets its parameters and pulls out measured data for each rotation angle.
    Measured data can be exported as .txt, .bmp, .png, .jpg.

Reference (transmitting) antenna with generator:

PC Software:

Mechanism with one of my colleagues doing some sort of raindance: