On 8/20/2013 1:00 PM, Tom W8JI wrote:
By squeezing or spreading turns to change mutual coupling between
turns, a T157-2 core can have almost 2:1 impedance shift! That tells
us it has considerable flux leakage.
So-called "self-shielding" and it's inverse, leakage flux, also depend
on permeab
On Tue, Aug 20, 2013 at 3:00 PM, Tom W8JI wrote:
> The ARRL in some publications, for example, teaches us toroids are
> "self-shielding". In fact, many toroidal cores have significant flux
> leakage.
>
That is for sure. I was following a thread in an SWL or AM BCB group a few
months ago, where
I had additional offline conversations with Rick (N6RK), and Carl (KM1H),
and below is my official response to my original post about RX antenna
transformer windings and complex impedance measured on the primary side of
the transformer depending on how they are wound.
There are several things th
On 8/20/2013 11:31 AM, Don Kirk wrote:
But I saw the complex impedance phenomena even with smaller diameter cores
(using different grade of material), and here is my actual FT 50-43 data as
an example.
One missing piece in understanding what you're seeing is the fact that
mu (permeability) is
If I can add my $0.02 worth here...
I have never found a better ferrite core for RX antenna transformers than
the Amidon BN-73-202 (Fair-Rite 2873000202). I also used to use
side-by-side stacked ferrite beads (eight FB-73-202 in two tight stacks of
4) to make "binocular cores", but that never work
I had additional offline conversations with Rick (N6RK), and Carl (KM1H),
and below is my official response to my original post about RX antenna
transformer windings and complex impedance measured on the primary side of
the transformer depending on how they are wound.
Rick N6RK said
> The way out
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 ind
Digging back through the archives I found lots of discussion about the
"best" transformer to use with flags, pennants and beverages. The
discussions included material type, and style (toroid vs. binocular), but I
found no mention about problems regarding the use of conventional toroid
cores in whi
