I finally decided that I am going to mount my Icom 208H in the trunk. Naturally, this will require the purchase of the 23ft separation cable (Part# opc-601/r) for about $50.00. (The cable that came with the radio won't reach)
As an experiment, I tried to extend the mic cable using standard CAT5 computer cable and it worked fine. I used about 25' of cable. So that problem is solved.
Now, before paying $50 for the longer separation cable, I was wondering if anyone has had any success in just cutting it in half, putting connectors on each of the cut ends, and adding a longer piece of cable in the middle.
I haven't cut it yet, but I'll assume there's some type of shield around the inside conductors.