I understand the issue, living as I do in UV world here in So Cal. I have not enclosed the cable, but I have run it under my eaves. The only place it's exposed is going up to the lnb.
I have also run the four wire sprinkler cable under the eaves. For that I have a junction box and stranded wire running to the motor and reed switch. The stranded wire is indoor appliance wire, but so far it hasn't failed or corroded.
I have actually had little issue with ultraviolet, but have had to, from time to time, scrape the corrosion off of the various copper wires to maximize connection.
I will be doing that again shortly, along with some other maintenance