Topband: Flag antenna.

[Rune Egil Øye]

Hi all

Just done my softrock V6.3 radio that i am going to use for receive here back home.
My plan is to construct Flag antenna for RX, but i don't have the binocular cores that are mentioned from different sources.
>From what i understand it is important to use isolated prim and sec winding this due to common mode current etc.
I have some 140-77 or was it 140-73 core and wonder if that can be used to make the transformer since i don't have the binocular core here.

Any sugestion here ? how many winding on prim and sec. 

73 Rune LA7THA.