ECE 4760: Final Project

Radio Station Tracker


Alexander Brady(

Peng Tian (


Our project is inspired by the commercial product, PicoDopp, which uses a similar scheme for foxhunting. Foxhunting is a contest where participants try to locate a transmitter, called the fox, simply by monitoring the signals it transmits.

Typically this is done using highly directional antennas — antennas that only receive signals from one direction. However, over short distances, especially within distances less than a mile or so, reflected signals can make these systems difficult to get accurate readings from. The only way to overcome this limitation is to use systems that do not rely on magnitude measurements.

We switch between antennas to simulate sinusoidal multiplication. We then measure certain frequencies our switching scheme injects into, which allows us to measure the phase difference between different antennas. Using the phase difference we can calculate path differences, and thus generate an estimate of where the signals are coming from.

We used multiple antennas to measure phase changes over different path lengths to get a bearing on a selected FM radio station. The image on the left shows the antenna we built for our project.


The antenna we built

pre amplifier mux circuit

Pre amplifier circuit and mux circuit hanging on our antenna