Simulation Results Franklin 4-element by 4nec2 software gives Gain =6.19 dBi & SWR=1.17:
Wire dia = 3mm
Gap between stub wires =6 mm (center-to-center distance between stub wires = 1.5 mm + 6 mm + 1.5 mm = 9 mm)
Optimum cable tap position = 45 mm from open end (or 69 mm -45 mm = 24 mm from shorted end)
franklin-4 element-3mm wire 6mm gap - pattern gain swr-R1.png . franklin-4 element-3mm wire 6mm gap - Sweep for Tap position-R1.png . franklin-4 element-3mm wire 6mm gap - input data-R1.png
Wire dia = 3mm
Gap between stub wires =6 mm (center-to-center distance between stub wires = 1.5 mm + 6 mm + 1.5 mm = 9 mm)
Optimum cable tap position = 45 mm from open end (or 69 mm -45 mm = 24 mm from shorted end)
franklin-4 element-3mm wire 6mm gap - pattern gain swr-R1.png . franklin-4 element-3mm wire 6mm gap - Sweep for Tap position-R1.png . franklin-4 element-3mm wire 6mm gap - input data-R1.png
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