[TowerTalk] Common-mode choke

[Jim Brown]

On 5/20/2014 7:05 AM, Jim Thomson wrote:
> if any choke is high resistance, it will work..provide the Z is sky high.
> Power is still I squared x R.

Yes. I have shown in my tutorial why choking Z on the order of 5K ohms 
resistive is a suitable design goal for most installations, and W8JI has 
reminded us of some where that's not enough. The only string of beads 
choke material that can get anywhere close to 5K on HF is the #73 
material that W2DU chose, and you need several hundred of them to get 
there. You would need that higher value for the high power amps you like 
to use. The largest #73 material bead is just large enough to fit coax 
like RG303. There's a discussion of his choke in the two referenced pdfs.

73, Jim K9YC