Topband: Ferrite Rods for Common mode choke?

[Jim Brown]

On Mon, 29 Aug 2005 11:48:23 +0200, Raoul Coetzee wrote:

>I have quite a few ferrite rods, the type used for loop stick antennas in
>portable radios, and was wondering if it could be used as a common mode
>choke if a bunch of them could be arranged  around a co-ax cable so that it
>forms a 'pipe'
>around the co-ax with no gaps between them?

Depending on the material and the frequency you need to suppress, it may be 
possible to use the parts you have effectively. See my applications note on 
this topic on my website, then try to find data on the rods you have to get 
some idea about what impedances they might provide. 

http://audiosystemsgroup.com/SAC0305Ferrites.pdf

http://audiosystemsgroup.com/Ferrites-Ham.pdf

73,

Jim Brown K9YC