Re: Inductance of Hoop Loop transformer windings


Bill M <radioexray@...>
 

> Like I said, it depends how nutty a fellow wants to be with this. (Jim,
> you're a good candidate - haha - You do have to be kinda nutty to sit
> down and wind up a bunch of LW-range cores for comparison!).
Thank you, Bill! I'm still stuck sitting most of the day, so it gives me something to do. W8DIZ, who owns Kits and Parts, once posted on QRP-L about permeability variations in -43 mix, but this is the first I've heard of variations in -61. Selecting toroids gets expensive at what they charge for the larger ones. A hard-core DXer living in a populated area might want to try it, though.
My experience has been mostly with -61. Haven't seen permeability variations in that the predicted inductance varied all that much. IOW, you could count on the same number of turns but the Q would be radically different. Maybe that only an insignificant change in permeability, for whatever its cause, might relate to be a Q-killer? Even if the answer were known I'm not sure that any vendors would/could address that.

I don't know what I don't know about these birds!

Jim, if you've got a bunch of wound coils hanging around and would like to see them with Q-test numbers I'd be happy to look at them on my Heath Q-meter. Its hardly a precision instrument for finite numbers but it suffices for comparing one against another.

-Bill

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