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Writer's picturextgaby

9:1 transformer for K9AY antenna.

Updated: Mar 8, 2021

Picture Schematics


primary 2 turns secondary 6 turns

Used material: 3 cores of 73 material Fair-Rite 2873000202


Input = 2 turns / Output = 6 turns

2 square = 4 / 6 square = 36

36 / 4 = 9

When Input impedance = 50 Ohms,

Output impedance wil be 9 x 50 Ohm = 450 Ohms













At 21.3 MHz impedance is 46 ohms + j10 ohms


Compensation is 34 pF @ 21.3 MHz









S21 Insertion loss for 2 devices:


The K9AY antenna is used at 160 meters and 80 meters.


The setup:





Insertion loss at 160 meters =


0.33 dB / 2 = 0.17 dB


This means a loss of 4 %





Insertion loss at 80 meters =


0.35 dB / 2 = 0.18 dB


This means a loss of 4 %











S21 insertion loss for 2 devices:



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