I’ve found a bunch of LMR400 for sale online. Most is CCA. Do I need solid copper conductors? Where’s the best place to buy that and connectors?
Real LMR400 from Times Microwave is Copper Coated Aluminum.
You do not need solid copper, unless you have a specific application that is calling for it. For most ham use, as well as scanners, short wave, GMRS, CB, LMR400 will be way better than what many others are using.
I'd echo what prcguy said, the Times Microwave EZ connectors are reliable and "EZ" to install.
But, if you just need a UHF connector, the RG-8 sized ones will work if you are soldering them on. But, honestly, I wouldn't go through all that with a good coax cable just to use UHF connectors.