How to wound two turns on a troidal core

How to wound two turns on a troidal core (for use in the range of 100kHz to 1MHz)

Takayuki HOSODA

In brief, we concluded that below 200kHz, winding silver-plated stranded wire evenly in three or more strands would cause less transmission loss,
and at higher frequencies up to 1MHz, winding wide insulated copper foil would cause less transmission loss.
PVC-coated wire and insulated stranded wire, whose only feature is their thickness, had no advantage above 50kHz.

D.U.T.
Core: Amidon, FT-50-43
Primary winding: 60T (30T of bifilar wounded ^φ0.3mm UEW wire) S21
Advantest, R3754A
Po=+5dBm Secondary winding |S21| @freq=1MHz |S21| @freq=50kHz

^t35μm×6mm
copper polyimide strip -4.766dB -0.909dB

3×12/0.18(0.3mm²)
silver plated FEP wire -5.927dB -0.394dB

2×0.3mm²
silver plated FEP wire -8.269dB -0.537dB

No image 1×0.3mm²
silver plated FEP wire -10.817dB -0.834dB

1×1.25mm²
PVC wire -11.742dB -0.595dB

21×^φ0.3mm
UEW wire -12.559dB -0.618dB

EXTERNAL LINKS

Fair-Rite Products Corp.

D.U.T. Core: Amidon, FT-50-43 Primary winding: 60T (30T of bifilar wounded ^φ0.3mm UEW wire)	S21 Advantest, R3754A Po=+5dBm	Secondary winding	\|S21\| @freq=1MHz	\|S21\| @freq=50kHz
		^t35μm×6mm copper polyimide strip	-4.766dB	-0.909dB
		3×12/0.18(0.3mm²) silver plated FEP wire	-5.927dB	-0.394dB
		2×0.3mm² silver plated FEP wire	-8.269dB	-0.537dB
No image		1×0.3mm² silver plated FEP wire	-10.817dB	-0.834dB
		1×1.25mm² PVC wire	-11.742dB	-0.595dB
		21×^φ0.3mm UEW wire	-12.559dB	-0.618dB