2023-01-23, 20:24:38
A dielectric such as RTV silicone or something similar. It would need to survive the heating due to soldering, but there is a high temp RTV that is red in colour for such applications. Another option is nothing at all. I used a copper foil tape to make a join on a piece of rg58...in my vehicle for the roof antennaa...still in use after 12 years...73