Microwave connector reference

BNC: Quick-connect half turn, same as on 10base2 ethernet. They can be fairly high loss at 2.4GHz, but they are common and cheap. 'BNC' stands for 'Bayonet Neill-Concelmann'. Popular opinion is that they're okay for 2.4GHz work as long as they're new, but ditch them if they are at all loose.

N: Threaded, larger connector common on many commercial 2.4GHz antennas. They perform quite well, although they are larger than some (but are perfect for thicker cable, like LMR-400.) 'N' was evidently Neill's connector.

UHF: This looks like a coarse-thread, big center conductor version of the N. Not usable for 2.4GHz, but frequently confused with the N. According to the ARRL Microwave manual, the Socket is an SO-239, and the Plug is a PL-259. Most call it 'UHF'. Avoid.

SMA: Very popular, small, threaded connectors. Work great through 18GHz. 'Sub-Miniature A'. Small and common, but no good for bigger cable (like LMR-400) without using an adapter.