Broadband signal search and direction finding at UHF frequencies

Abstract

A technique for finding the strongest signal's power and direction using a receiver system in the lower UHF band is presented. For this purpose, a log-periodic dipole array antenna, a power sensing RF circuit and a microcontroller system for controlling a stepper motor are designed and tested. The receiver system rotates the antenna 360 degrees in azimuth with the stepper motor and measures RF power. The measured power is represented in the form of a DC voltage and stored in the memory of the microcontroller for comparison. Once the strongest signal and its direction are found, the antenna is rotated to that position and locked.