question of transformer used in dipole

1:4 Unbalanced to Balanced transformer used in dipole, what is the meaning of 1:4? Does the impedance ratio mean that of input impedance of dipole or the impedance of each arm of dipole to 50 ohms? Thanks.

an increase in impedance 4 times.
if the dipole is 50 ohm then the imp after the transformer is 160 ohm

4 times 50 = 160 ! Well done, good answer!

Thanks.