You could say splitting hairs that its a unun.
Unbalanced in at 300 ohm, and unbalanced out at 75 ohm.
Being a transformer it'd work either way.
That looks far too small for the FM band at around 100MHz??
Each driven (electrically connected) dipole should be approximately 5% less than a calculated half wave, end-to-end; at 100MHz, 3 metres wavelength, that is 142.5cm (56 inches) end to end.
If the dimensions are wrong by more than a few percent it will simply not work well, if at all.
This is some design info and calculations for building a Yagi style antenna:
It is an interesting design.
Looks like it requires a FM transmitter and need adjustment to receive a specific station.
Glad you caught before I disassembled it.
Could you give more details on how to scale it 3:1?