Topband: RX antenna transformer winding (pure resistance transformation issues)

[Richard (Rick) Karlquist]

On 8/16/2013 8:06 AM, Don Kirk wrote:

> discussions included material type, and style (toroid vs. binocular), but I
> found no mention about problems regarding the use of conventional toroid
> cores in which a pure resistive load on the secondary appears to be a
> complex impedance (resistance and inductance) on the primary side of the

The way out of this dilemma is to use a smaller toroid core than
the 1.14 inch diameter core you currently have.  This is a
RECEIVING antenna after all.  What you are seeing is leakage inductance.
The leakage inductance should scale linearly with core diameter.
The capacitance should also scale.

Having said that, the small amount of leakage inductance you are
seeing even with the large core with separated windings is
nothing to worry about.  I would rather tolerate that and get
the benefit of the reduced capacitance from winding to winding.

Rick N6RK