I'll send you enough solderable RG-59 (Belden 1505A) for free to make the harness and you can get two PL-259s and a T adapter at any R/S and that will mate with 50 ohm coax. Or I'll make a harness using F connectors and an F type T adapter for 75 ohm connection for $5 + shipping. Send me your address off line and let me know which one you want.
I'm sorry for the misunderstanding. I looked at RS website and they don't even have RG59 that is solderable. So i'm not sure if it's easy to come by locally. Then i've have to order online and then order connectors and all that. I don't even know what F T connector to use as RS site only shows splitter and diplexers. I didn't realize you were going to test it. we can do it your way if you still want.