You have it backwards. The 1/2 wave coaxial balun converts 300 ohm Balanced to 75 ohm Unbalanced. Balanced means neither side is grounded like in a folded dipole. Unbalanced means one side is grounded like the shield of coax.You use a 1/2 Wave balun to get 300 Ohm unbalanced to 75 Ohm Balanced. I am looking to get 150 Ohm unbalanced to 75 OHm balance. So is it a simple matter to replace the 300 Ohm Resistor which a 150 Ohm restor ?
The 300 ohm resistor you see in the diagram is not an actual resistor that is part of the balun, it represents the 300 ohm impedance of the antenna for the simulation. The two diagrams above were originally posted on this forum by Brian Beezley K6STI.
What are you trying to connect to 75 ohm coax?