[Amps] 160m mosfet linear amplifier problem with ferrite cores

[sasas asasas]

i think that the proper material is 43 or 77 for frequences between 1-2mhz. i search in some internet sites and i found these:
31 Material
A MnZn ferrite designed specifically for EMI suppression applications 
  from as low as 1 MHz up to 500 MHz.  This material does not have the dimensional 
  resonance limitations associated with conventional MnZn ferrite materials.  
  Round cable EMI suppression cores, round cable snap-its, flat cable EMI suppression 
  cores and flat cable snap-its are all available in 31 material.

43 Material
This NiZn is our most popular ferrite for suppression of conducted EMI 
  from 20 MHz to 250 MHz.  This material is also used for inductive applications such 
  as high frequency common-mode chokes.  EMI suppression beads, beads on leads, SM beads, 
  multi-aperture cores, round cable EMI suppression cores, round cable snap-its, 
  flat cable EMI suppression cores, flat cable snap-its, miscellaneous suppression cores, 
  bobbins, and toroids are all available in 43 material.

So, the 31 material supresses frequences from as low as 1 MHz up to 500 MHz! So, i think that is not suitable for 1-2mhz operation. What do you believe????

Also see here: http://users.catchnet.com.au/~rjandusimports/ft_mat_1.html  <-- you can see that 43 or 77 material is suitable for 1-2mhz frequences. For 31 material no one refer.