[Elecraft] my KPA1500 and 160M

[Josh Fiden]

No.  At low frequencies hysteresis loss dominates. Soft ferrites have high resistivity. Eddy currents increase with frequency but 160m is still fairly low. 

In SMPS transformer design we look at applied volt*seconds. When the applied v*s goes up, as would be the case with high SWR, you push further out the BH curve increasing hysteresis loss. With each cycle, the area inside the BH curve determines the loss (heating). As you approach the horizontal part of the curve (saturation), inductance collapses and the winding looks like a short. Same if core hits Curie temp then mag domains can no longer be aligned. 

Soft ferrites are not permanent magnets, they are NOT in fixed alignment. Magnetic domains are flopping around with the applied field. 

Hope this clarifies something. Hihi

73
Josh W6XU 

Sent from my iPad

> On Sep 2, 2020, at 10:58 PM, Adrian <vk4tux at gmail.com> wrote:
> 
> core heating is affected only by the AC (induced eddy *currents*) content of the signal.