UPDATE

So, we checked my radio on a friend's setup in his car. The radio booted fine, so I thought I must have had the pinout wrong. I started over, followed the diagram exactly, and it didn't work (same error). This was a 6" piece of Cat5, mind you. I then made a loop in the wire, tried it again ...

Hi everyone,

New here, please excuse the question if it's already been answered.
I have a VHF high power astro spectra, model T04KLH9PW3AN designed for the W3 head. I'm attempting to make my own cable, since the "Y" cable seems to be unobtanium, either from cost or availability. I wired a male ...