Is it not funny that you talk about 75 ohm for antenna impedance?
The secondairy is around 70 ohms; the two chokes also a bit around the 70 ohms and then the waterbath also a 78 ohms....
Now which parts are part of the powesupply and which parts are part of the LCR load?
Hint: just puzzle a bit...
Look for an honest balance.
Impedance balance of components who have DC resistances that should be in balance for ideal matching...
cheers