Antenna Foxhunt Laboratory

Antenna theory is one of the most challenging subjects to study in electrical engineering. Conversely, the implementation of the theory can be fairly straightforward in certain scenarios. In a recent offering of a wireless communications systems course, students took part in a unique two-part laboratory on antenna basics covering antenna design and construction along with a competitive foxhunt . The antenna design portion of the laboratory had the students choosing an antenna topology from a range of choices including dipole, inverted-V dipole, folded dipole, 2 or 3 element Yagi and diamond or square quad antennas. Constructing these antennas using pegs and pegboard, the students then used an SWR meter to tune to their specific frequency in the FM band. The students further built the proper balun to match and drive their antennas. Since low-power FM transmission is unregulated, the students were then able to measure the radiation pattern of their antennas in order to predict directivity. Taking place in a large open room with minimal obstruction in the near field, the students transmitted across the room to a receiving monopole antenna, measuring both bandwidth and radiation pattern. With this knowledge in hand, the students then constructed a frequency-scaled (hence, spatially-scaled) version of their antenna to operate at the HAM radio band near 450MHz in order to participate in the foxhunt. Using the known directivity and sensitivity of their antennas, the students participated in a competition to locate a hidden HAM radio transmitter