[Elecraft] OT; large ferrite toroid core?

[Jim Brown]

On 10/21/2021 6:51 PM, Fred wrote:
> Jim, K9YC, has done a ton of research on ferrites for baluns and 
> chokes.  I think jim at k9yc.com will get you to his published results.  If 
> 6.6 uh/4 turns is correct, you might be able to figures out the ferrite 
> mix from his data.

Unfortunately, 99.9% of stuff like this that falls in our lap are little 
of any value for RFI suppression. This looks like a component intended 
for use as an inductor in power circuits; without winding experimental 
chokes and carefully measuring them with a VERY well calibrated test 
instrument and specially designed test jig, we have no way of knowing 
anything about the part. I measured nearly 1,000 chokes wound on a 
material that I'd already determined was the best choice for use at HF.

Bottom line -- if you need to kill RFI, study the app notes on my 
website, buy the specific parts I recommend, and apply them as 
recommended to wiring on noise sources, or wiring on victim equipment.

73, Jim K9YC