What kind of Ferrite Core ?

Hi, SOmebody can help me to choose a ferrite core .

I have signal between 800 Khz and 5 Mhz !

I would like to have a minimum insertion loss for this bandwith!

The most popular FT-50-43 have an Fmin too High
:( :(
Best Regards.

this might helps

there are more at
http://www.pulseeng.com/Products/Literature/default.htm

Ferrycube (fore philips)have many good high frequecy ferrite products.

you can probe this...

http://www.mag-inc.com/library.asp

just I want it too