[TowerTalk] [Bulk] Cutting a FT-240 type 33...in half

[Steve Hunt]

Jim,

That is such a revolutionary statement that I felt I must investigate 
it. So I loosely wound 4 turns of PTFE wire on a Type 43 toroid - the 
wire was barely touching the toroid. The impedance measured around 200 
Ohms at 10MHz - almost entirely resistive. I connected it across my 
tuner, adjusted for a good match, and then applied 20W at 10MHz for 5 
minutes.

At the end of 5 minutes I touched the wire and then the toroid. The wire 
was barely warm, but I scolded my finger on the toroid!

There's no doubt at all that the dissipation mechanism is within the 
ferrite toroid, not the wire; if the wire gets hot it's because it's in 
contact with the toroid.

Or perhaps I completely misunderstood what you are claiming?

Steve G3TXQ



On 10/02/2015 21:18, Jim Brown wrote:
> There is dissipation in a ferrite core choke in the resistance coupled 
> from the ferrite core. It is the coax shield that gets hot, not the 
> ferrite (although the heat in the coax may be transferred to the 
> ferrite material).