Is the IEM transmitter's antenna 75 or 50ohm?

Hi mates, I hope to find somebody here expert of IEM transmitters,
I need to pack mixer, microphone receiver (UHF) and G-MARK G5.1IEM UHF into a Case, cause of the small space available the IEM will be placed over microphone receiver, so the antennas will be very close each other. In this way I’ll probably saturate the microphone RF stage, reducing the coverage, so I want to move far away the antenna of IEM, on the opposite corner, and fix it by a metal square on the case.
Now how can I bring the trasmitting line there, I’ll use a quality cable, but should it be 75 or 50 ohm?
Thank you for you kind answers