There is an unknown ferrite toroid. I would like to figure out whether it can be used in an audio transformer, or maybe in a 1:4 transformer on given HF frequency.
The experiment I came up with is following. I can wind a 1:1 transformer using this core, connect one winding to a signal generator and the second winding to the oscilloscope with a 50 Ohm dummy load. Then I can measure Vpp vs frequency with and without the transformer and calculate power loss as 1 - (Vpp_with/Vpp_without)^2.
Is this an adequate experiment? Using this method I could also estimate pase shift and temperature stability. Is there anything else I should be mindful of?