by way of Bill Tippett <> topband-bounces at
Thu Dec 8 17:48:08 EST 2005


If you are using the autoformer (single winding with a tap) design 
from Tom's web site, I'm not surprised to hear about the limited high 
frequency response. Autoformers are not particularly broadband (see 
Fig. 3-12 in W2FMI's Transmission Line Transformers book). And they 
can be sensitive to winding technique, but more so on a toroid than a 
binocular core.

I'd recommend a transformer with separate primary/secondary 
windings.  5 turns / 7 turns on the same BN202-73 core will give you 
an accurate 1:2 impedance ratio and will easily cover from BCB to 20M.

73, Gary

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