Topband: Beverage Feed Line Choke Installation

[Jim Brown]

On Mon, 1 Jun 2009 19:43:43 -0400, n4is wrote:

>My place is very noisy and I may be over killing the common mode noise.

I understand your logic of creating a two-stage common mode filter with 
chokes and multiple ground rods, with each choke being a series element and 
each ground rod being a shunt element. When overkill is easy and 
inexpensive, and when there are no tradeoffs, by all means do it!  I also 
agree with your strategy of choking other cables in the vicinity. 

Several months ago, I measured the common mode impedance of all the 
telephone RFI filters I could find. I was surprised at how much common mode 
impedance was for those that had a repution of success. In the world of 
common mode chokes, more is definitely better so long as you're not 
degrading the differential circuit, and nothing we do with coax can hurt 
the differential circuit short of making the coax too small to handle the 
power. 

Many thanks for sharing your work on this. 

73,

Jim Brown K9YC