Just post a link to the manual.
http://bama.edebris.com/manuals/radiocit/705a
Interesting that both this and the SG-8 use just two tubes.
You definitely need to use shielded connectors and cable on the high output source since otherwise it will broadcast to the radio. Switching out the banana jack for a BNC will probably require you to enlarge the hole in the panel. Something like this.
https://www.mouser.com/ProductDetail...zdb4bk0FGlA%3D