Using two lengths of coax as twin feed
If you are in a situation where using ladder line or open wire feeder is not an option or difficult where you have to run it through a wall and you cannot screen it, then consider using coax two pieces of identical length which can be run almost anywhere.
For a wire delta loop or dipole simple connect the inner cores of the coax cables one to each side of the antenna at the feed point and join the braids from each length together and insulate with electrical tape or heat shrink.
Run the two lengths of coax into your shack as required attach the inner cores to each side of your Balun 1/1 or 4/1 and join the braids of each length together again the same as the feed point and insulate them .
Then use a patch lead to connect your Balun to your ATU as normal unless your ATU has an inbuilt Balun where you can connect the feeder directly