Antennas

摘要

Continuing the experimental and measuring theme of last month's 'Antennas' column we will have a look at making polar diagrams of beam antennas. This can be done quite simply at VHf by energising the beam antenna with a QRP transmitter and using a dipole antenna and field strength meter (FSM) to measure the field strength as the beam antenna is rotated. Furthermore, HF beam antennas can be modelled using VHF antennas as described in [1].