[RFI] Ferrite Loops

[rrath at charter.net]

Hello to the group and new to the group. Here is my question:

I bought some ferrite loops to slide over RG/8 type coax. The seller 
does not know of what mix they are made of. I want to help 
eliminate RFI/TVI when transmitting on Hf from my RV. How many 
should I slip on? Is there a site I can go to that would help answer 
this question? I know it would help if I knew what mix they are.  
Thank you for your help.

Rod kc7vqr