[old_tv_nut]

This should be fine.

I can't find info on the TV-4, but assuming the output is 75 ohms, the final check of your lashup is to put 75 ohms (or the nearest resistor value you have, 68 or 82) across the end of the cable (input and ground leads of your detector), and see that the response is still flat. (The 75 ohms will match the cable and swamp out any loading the detector does.)