That's EXACTLY what I thought, until just a few minutes ago. I did a little research and found a FAQ at wilson website: http://www.wilsonantenna.com/faq.php
Wilson's exclusive impedance matching transformer is connected through the external wire at the bottom of the FGT and Flex series of antennas. It is NOT a ground wire to increase the ground of the antenna, although using the lead does make the antenna DC ground. It is used when you are not able to get below a 2.0:1 SWR even after tuning. This generally indicates a mismatch of impedance between the coax and the antenna. This can be caused by poor ground but is generally attributed to the mounting location. It re-inserts 25 ohms impedance at the antenna feed point and brings the system back to the 50 ohms required. It is not a tunable device, therefore it is not fooling the radio into thinking the system is matched. It is actually matching the antenna and feed point to the required 50 ohms impedance for the coaxial cable. The most often time it will be used is when the antenna is mounted on the top of tool box in the bed of a pick-up, or on the passenger side of a tractor using co-phased antennas.
You have the choice of either cutting it off or taping it out of the way. In making your choice, consider if you may move the antenna to another vehicle, that installation might require the lead. For the most versatile use of the lead, simply lay it alongside the fiberglass and tape it in place. Using electrical tape will offer the easiest method and offer the best protection against weathering conditions.
I might be using the wrong cable too. The FAQ says:
If you are using less than 1000 watts, and a single antenna, use an 18' length of RG-58/AU. This cable is 95% shielded, stranded center, with 50 ohms impedance. If your power is less than 2000 watts, then change to the RG-8X type (also called Mini-8 or Super 8). For co-phased antennas with less than 1000 watts, use RG-59/AU. For power less than 2000 watts, use RG-11/AU. Both co-phasing cables should be 18' in length on each side. Wilson has available a high quality line of coax cable, and may be viewed at: Coaxial Cable.
Using the recommended length of 18' of coax cable can sometimes result in an excess amount of cable in the cab. This excess cable should be stuffed underneath the dash, under the carpet, or use some other means of hiding it. It should NOT be coiled into a neat roll or coil. This creates an RF Choke and de-tunes the antenna system, in some cases to the point of not being able to get the SWR down to an acceptable level.
And, use of the 3' whip for HAM
I some things to try now at least. How much does it take to get started in HAM?