Or, install a small surface mount junction box up high and make your terminations there, so you can use whatever you find to extend it.

Splices don't need to look bad, but they often do. I use HeatNSeal butt splices for speaker, power and control wiring- the sleeve melts and shrinks, the metal ferrule makes the connection and the glue inside seals both ends, so water won't be a problem. This can be covered with shrink tubing. I usually cover coax splices with this, too.