Hi friends, I am designing a common mode choke, EE5.0 core, impedance is 1200ohm MIN at 80M, L is 400uH MIN, I made many samples to test, however it is difficult to meet 1200ohm MIN at 80M, would you please give good suggestion! thanks in advance.

 

What is "M'?

 

I can only guess op means 80-meter or 3.75MHz.

 

"I can only guess"

That is exactly why those who want specific help need to explain their problem as clearly as possible, with schematics, pictures and CORRECT USE OF STANDARD ABBREVIATIONS so that those who might offer help do not have to guess what they meant and go of on some sort of tangent

M = mini, micro, mil, mega, meter, many, mine, monday ????

 

sorry, my friends, I did not say clear, 80M is 80MHz , need impedance 1200ohm MIN at 80MHz, thanks!

 

80MHz is a bit different from 3.75MHz. I guess I guessed wrong.

 

No, you guessed right, given the context. He stated the problem clumsily.