Not sure if the above replies clearly answered this for you, but I figure one more reply won't hurt….
Well, no. LMR400 is good for hobbyists as it's relatively inexpensive, easy to install, and performs better than anything you'll find at Radio Shack. Best of the best is stretching it. You can certainly get better cable with hardly any effort, but it's going to cost more, be harder to install, but it will perform better.I know LMR 400 is pretty much the best of the best when it comes to coax...
I'll give you $5 for a 50' run of RG-214 with N connectors on both ends. Me thinks you're thinking about LDF4-50A connectors, not LMR-400 connectors. If you examine the provided link (that justifies my $5 price) you'll notice that the same connector is used for both LMR-400 and RG-214.I would say that the whole feeder system with RG214 would cost less than a single LMR-400 connector.
For a short run of 50' or less LMR400 is in my opinion overkill. Why not try simple RG214, it is a double braid coax, very flexible and in plentiful supply from just about any cable vendor (Anixter usually carries some). The basic N-Type either crimp or solder works well and can be replaced easily if needed, these come in PL259 or N-Type also and are inexpensive. I would say that the whole feeder system with RG214 would cost less than a single LMR-400 connector.
Standard PL-259 connectors will screw right on to LMR400. Just fold the braid back and screw the connector on, then solder the center pin.