I've been trying to put together an impedance transformer on the Amidon
BM-73-202 binocular core. It is to be used on a flag RX antenna for 160m so I
need about a 950:50 (19:1) transformation. The published AL is 8500 mH/1000
turns. This translates to 8.5 mH per turn. From a Handbook formula, I
calculated I need 1.4365 mH on the HI Z side and 0.0765 mH on the Lo - Z side.
As you can see, even one turn thru the core exceeds these by a large margin.
Do I need a core with a lower AL? Seems like many folks recommend the
BN-73-202 though with a 3:12 (W7IUV) or 1:4 (W8JI) turns. But I can't arrive
at these numbers by equation. I'd like to learn how this works rather than
just build it without learning.
Thanks all. Steve KK7UV.
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