Topband: RF choke/balun

[MR TREVOR DUNNE]

Hi All

I am planning on making an RD Choke for my 160m inverted L and was wondering what others use,

I was thinking of 3 stacked ft240-43 cores and maybe 10-12 turns of some rg316 or the like small coax,

With 61 or 31 be a better material to use and do I need more or less turns,

I'm loosely working from the G3TXQ website where he did like of measurements on different chokes, but not we're great on 160m,

I'd like to end up with something like a balun design 1116d but with a lot less money in it,

Thanks
Trevor
EI2GLB