[captainclock1988]

Ok so from what I've seen of pictures of the RCP Model 705A Signal Generator, it seems that the original RF Output plug was basically just a hot lead all by itself and then the ground lead was independent of it and hooked up to the banana plug jack that's marked "GND" next to the AF Output jack.
So it seems that all I need is some RG-58 Coaxial cable that I could wire one side to my already existing mic plug and then the other side wire up to an insulated red colored alligator clip, and then have a regular black banana plug wired to a 4' length of black wire on one end and the other end a black insulated alligator clip attached for the ground lead. 

Here's the picture I found posted below showing the original RF-Output test lead.