Fred, while a 5/8 wave antenna has about 3.5 DB of gain over a quarter wave, it is also a little over 4 feet tall. That makes it a challenge to install a 5/8 wave antenna in an effective place, while clearing the garage doorway, or the parking garage roof down town. So, while it has no gain, don't underestimate the effectiveness of a simple quarter wave antenna mounted as high as possible on the vehicle. For 2 meters, a quarter wave is only about 19 inches tall. Since it doesn't wave around in the breeze as much as the longer 5/8 wave whip, it also tends to have less signal flutter. There will, of course, be some fluttering as you travel. This is caused by the simple fact that the antenna is in a constantly changing location in respect to the other station. The method you use to mount it will be driven in part by where you wish to install it, and by whether or not you are willing to put a hole in a metal surface on the SUV. One "no holes" option is a mirror mount, which clamps around the arms of certain types of side mirrors. Some of these can also be adapted to fit luggage rack rails, the top of a rear-mounted ladder, etc. You can find them at Radio Shack, or at many truck stops. If the roof is metal, you can use a magnetic mount, but you don't really want that to be a permanent install. Mag mounts are fine for temporary use on trips or for events, but don't leave them there any longer than necessary each time you use them. No matter how strong the magnets, and how tight against the roof they hold the base of the antenna, you will sooner or later find yourself with a patching and painting problem caused by moisture buildup under the base. I have known of people who clamped a steel plate to a luggage rack rail, etc, ran a ground wire from the plate to the frame of the vehicle, and sat their mag mount antenna on that plate. The advantage here is that you don't scar the vehicle. If your SUV is fiberglass, or has very little exterior metal, you will need to look at a half wave antenna. A half wave is not as dependent on a good ground plane beneath it as a quarter wave or 5/8 wave antenna. Many of the dual band 2 meter/440 antennas are a half wave on 2 meters. Glass mounted antennas are also usually half wave. A glass mount is another option, but be advised that some types of automotive glass do not work well with these antennas, especially on 2 meters. The antennas stick just fine, but the glass doesn't allow the RF to pass through very well, and can make tuning a challenge if not impossible. Hope this helps. Mike, K5XU