Measurments on Kenwood YK-88CN CW Narrow filter.

Input / output impedance = 600 Ohms

Measuring setup:

Transformer impedance ratio = 600 / 50 = 12

I have ended with 3 turns / 10 turns.

Insertion loss measurement of the setup showed 0.5 dB witch is negligible.

The results:

- 6 dB Bandwith = marker 5 - marker 3

= 8.83082 - 8.83054 = 280 Hz (spec. min +/- 125 Hz or more ==> > 250 Hz)

- 60 dB Bandwith = marker 6 - marker 2

= 8.83112 - 8.83010 = 1020 Hz (spec. min +/- <<600 Hz or less => < 1200 Hz)