[RFI] Bitcoin Mining GPU interference

[Jim Brown]

I didn't trust Steve's designs, so I checked them out by buying 40 cores 
from four vendors over two months, measuring and selecting cores at the 
limits of measured characteristics, and winding chokes on cores at those 
limits values. I could not reproduce his results. The issue is 
production tolerances and the much higher Q of the #52 material.

The ONLY material suitable for HF chokes is #31.

Steve was a very good technician, but not a good engineer, because he 
didn't understand product manufacturing tolerances. He measured only a 
few cores. For my work on chokes, I measured more than 100 #31 cores.

As a young EE at Motorola, I learned that every part out of the box has 
to work, with every other part out of the box. Ferrites are wide 
tolerance parts.

73, Jim K9YC

73, Jim K9YC

On 3/24/2026 2:27 AM, vk3od--- via RFI wrote:
> The G3TXQ Type 52 filters looks very impressive wound on 3 X Type #52 cores that will just about cover most of the HF spectrum with high choking impedance. It will however double my cost.