Installing a CB unit in an Airstream Classic

[Ramblin Boy]

I would like to install a Cobra handheld CB speaker/mike (which I used to have in an SUV) in my 2005 Airstream Classic 30' trailer. It has an under-the-dash bracket with the usual co-ax antenna cable connector and wiring for an electrical connection. I don't want to have wiring and cable all over the place, however, in order to achieve the goal. I thought I was in good shape because the trailer had a curbside exterior CB antenna mount but after looking at it carefully, I am not so sure.

It is a plastic body mount of the usual type with a socket for an antenna, but unlike a car body arrangement, has a phillips head screw fastening below the plastic to something behind the panel. The interior connection is on the wall at the right side of the sofa at about the level of a person's head when sitting and consists of two threaded studs in parallel. The lower is probably the connection for the phillips head screw but the upper stud has washers and nuts like you would use to connect wiring to a stereo speaker. I can't figure out how this worked or whether it could be used for my equipment.

I had planned to get a Firestik ground plane antenna kit (Cobra tells me I need this) but I guess I need to know how the previous mounting arrangement worked before I take the plunge. Maybe I need to start fresh. Thanks in advance for any thoughts or advice.