DF6QV 4-Square Antenna Analysis: Theory, Simulation, and Practical Construction

This technical document provides an analysis of 4-Square antenna systems, covering theoretical principles, simulation results, and practical construction considerations. The resource details components such as radiators, couplers, phasing lines, and ground systems. It examines the influence of ground conditions and element spacing on antenna performance. Various 90-degree couplers, including the 3 dB hybrid coupler and the Reed Fisher coupler, are analyzed using the LTSpice simulation program. Data presented includes power splitting, phasing, and bandwidth characteristics. The document quantifies power, voltage, current, and losses within a 4-Square system, addressing relays, capacitors, inductors, radiator radial systems, and cable losses. System impedance, bandwidth, SWR, isolation, and mutual coupling are discussed. Practical aspects cover radiator construction, common mode chokes, phasing boxes, dummy loads, and remote control systems. Field test observations for 40m 4-Square antennas are included, with specific examples from operations like 5A7A and VP6DX.