I have a reel type antenna I’d like to use for listening to shortwave with my Grundig Satellite 750. The antenna wire ends with a 3.5 mm plug. The side of my Grundig has a spot for a BNC plug labeled for shortwave . Can anyone tell me exactly what adapter I’m going to have to get to plug a 3.5 mm jack into BNC plug? I’ve seen BNC connectors that mate with many, many other connections but I have not found a BNC plug that I can directly plug a 3.5 mm jack into.