The dominant Ferrite 43 material transformer loss is magnetizing admittance core loss.

Given the following inputs:

μ_{i} = Initial Permeability

Lμ_{i} = uH at Initial Permeability

F = Frequency MHz

μ' μ" = Complex Permeability at F, from
Fair-Rite 43 MATERIAL Permeability (CSV) file

Core Admittance can be computed using the following equations:

L = Lμ_{i} * (μ' / μ_{i})

X_{s} = 2π * F * L

Q = μ' / μ"

R_{s} = X_{s} / Q

Z = R_{s} + i * X_{s}

Y = 1 / Z

Magnetizing admittance is the real part of the complex admittance Y.
Fractional loss equals load admittance divided by sum of load and core magnetizing admittance.
The equation for a 50 Ohm load is:

fractional loss = 0.02 / (0.02 + Re(Y))

dB=10*log10(fractional loss)

Magnetizing Admittance Core Loss at a given frequency, such as 13.5 MHz, can be computed and plotted
over a range of initial permeability inductance values.

Inductance at initial permeability ~= 3 uH

Measured Insertion Loss at 13.5 MHz = 1.39 dB

Mismatch loss for SWR 1.56 = 0.22 dB

Measured Insertion Loss minus Mismatch Loss = 1.17 dB

Plotted Magnetizing Admittance core loss for Initial permeability of 3 uH ~= 1.3 dB

Measured Insertion Loss at 13.5 MHz = 1.39 dB

Mismatch loss for SWR 1.56 = 0.22 dB

Measured Insertion Loss minus Mismatch Loss = 1.17 dB

Plotted Magnetizing Admittance core loss for Initial permeability of 3 uH ~= 1.3 dB

Inductance at initial permeability ~= 44 uH

Measured Insertion Loss at 13.5 MHz = 0.14 dB

Mismatch loss for SWR 1.20 = 0.036 dB

Measured Insertion Loss minus Mismatch Loss = 0.104 dB

Plotted Magnetizing Admittance core loss for Initial permeability of 44 uH ~= 0.1 dB

Measured Insertion Loss at 13.5 MHz = 0.14 dB

Mismatch loss for SWR 1.20 = 0.036 dB

Measured Insertion Loss minus Mismatch Loss = 0.104 dB

Plotted Magnetizing Admittance core loss for Initial permeability of 44 uH ~= 0.1 dB

Inductance at initial permeability = 4.29 uH

Inductance at initial permeability = 23.6 uH

Inductance at initial permeability = 23.6 uH