The length of your wire is critical, and the orientation in a loop is less than ideal to capture the radio waves. A half wave at the center of the FM band would be about 160 cm. A full half wave antenna is not practical for a fender mount, so the usual approach is a quarter wave antenna. This would be around 75 cm or about 30 inches. If you notice, automobile fixed antennas are standardized at around 30 inches (actually 30.5 if I remember correctly). It might work OK, but one of the hidden antenna's will work better if you're wanting to lose the fender mount - http://www.amazon.com/Mr-Gasket-6100.../dp/B003IJXU5C