Topband: QST Jun 06 RX Loop

Richard (Rick) Karlquist richard at
Thu May 18 09:56:51 EDT 2006

> Place ferrite beads over the ends of the shield adjacent to the 
> shield gap.  
> You will now find that the shielded loop no longer receives anything.
> What happened to the shield's permeable magnetic coupling to the center 
> wire?  Could it be that currents on the shield's surface were travelling 
> around the end of the gap to enter the inside of the shield and 
> then couple 
> to the center wire?  Or mebbe the ferrite beads destroyed the shield's
> ability to continue to be magnetically permeable?
> If someone can explain this, I would like to hear it.
> 73, Doug / NX4D

Explanation:  the ferrite beads are also surrounding the inner "antenna".
So that "explains" why it goes dead.

Rick N6RK

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