QRP 4:1 Balun for OCFD

thingiverse

he QRP 4:1 balun is for an off center fed dipole antenna. It should handle up to 20 watts comfortably. It uses a 2 core 4:1 design. Windings are radial, with no crossover across the toroid opening because of the center support post. Both toroids sit over the center post with a piece of insulating material (cork, foam, etc) to prevent contact. QRP 20 watt 4:1 parts list: 2 type 43 toroid 25.4mmx15.5mmx6.35mm (Mouser part # 5943001301) 2 #8-32 stainless screws 2 #8-32 stainless nylon lock washers 2 #8 stainless split ring lock washers 2 #8-32 stainless nuts 2 spade terminals for internal connection to the lead screws 1 chasis mount BNC female connector 22 guage enamel magnet wire 4 #4-1/2 stainless sheet metal scrws for attaching the lid