Jakern,
Doug is right, An antenna mounted horizontally won't work very well at all. It's all about Polarization! Antennas in two way radio systems work best of they are oriented (Polarized) the same. Look around and you'll see that virtually all mobile antennas including CB are mounted vertically on vehicles, and base stations for that matter. Your antenna will be far more efficient if it, too, is mounted with the same polarization as the stations you wish to talk to. The military antennas you see bent over and tied down, are longer and for frequencies much lower that CB, and when tied down only work very well for very short distances, like a few hundred feet, such as between units a in a convoy. When they want or need to communicate over a longer distance they unhook them and have them verticle. It's just that they're are so tall that they would be hitting traffic signals, overhead wires etc. when driving on the highway, so they tie them back for transit.