All of the modems that have a antenna port are going to require a cable called a "pigtail"
One end of this has a proprietary connector specific to your modem brand and the other end is usually a FME/male connector:
The antennas made by Wilson like the Omni Trucker, glass mounts, mag mounts etc all have a cable that terminates in a connector called a FME/female:
You would think, looking at them, the one with the threads on the outside should be the "male" end because, well..it screws into the other one. But nope, that's not how they work in the antenna world.
The connector that has a pin inside is the male...the one that has a hole to receive the pin is the female. I know, sounds kinky, but that's the way it works.
Suppose you want to connect to a Yagi, Panel, or Grid antenna? They have yet another connector that is popular called a N connector which also has its male/female counterparts:
These fittings are much larger and heavier than FME and are also used to extend the distance between the modem and the yagi, panel, grid antennas with a good quality low-loss cable like LMR400.
This will require an adapter between the N fitting and the pigtail. This is a N/male to FME/female adapter:
Make sure when you order the antenna that you know what type of connector is on the end of it and get the appropriate adapter. The setup for a Yagi should look like this:
The setup for a standard antenna you can buy at Radio Shack or a cell store should look like this:
Cable and connector size comparison:
Cable signal loss calculator here.
Getting the parts you need the first time will remove a lot of the frustration in setting this gear up. Have fun.