...i cant understand why a 1:1 current balun which isnt a transfromer is so far away from 50 ohms...

Did you try winding the cores with thin coax instead of two parallel wires?

Assuming that you used a two-wire transmission line, with one end connected to the coax and

the other end connected to the load, if the load is a perfect 50 ohms then the impedance seen

by the coax will depend on the characteristic impedance of the two wire line used to wind the

balun and the electrical length of it.

If the two wires have an impedance of 50 ohms, then there shouldn't be any impedance

transformation effect. But it is difficult to make a 50 ohm parallel-conductor line because it

requires a spacing that is less than the wire diameter (at least for round conductors.)

Sometimes you'll see recommendations that the two wires be twisted together before being

wound on the core - this lowers the characteristic impedance even further.

Why does this matter? If the characteristic impedance of the line (made from the two wires

wound on the core) is 100 ohms, then with 1m the SWR would be 2 : 1 on 20m just due to the

impedance transformation. The situation gets a bit more complicated when the turns are wound

adjacent to each other on the core because a single wire can couple to the turns on either side

of it.

Twisting the wires together and/or covering with heat shrink tubing to hold them together may

help by lowering the impedance and/or providing more coupling between the desired wires and

less to the adjacent ones. Winding the core with the same number of turns of coax cable is

even better at providing the desired impedance and minimizing unwanted coupling between turns.