Receivers use a tunned antenna either fm or am. For those old enough remember when you bought the am/fm/cassette player for your car to replace the factory cheapo radio the instructuions told you to tune the radio to the loudest station at the high end of the dial then adjust the screw inside the cassette door what you were doing was tunning the antenna. with FM the antennas are all the same pretunned length. If the antenna is too long it's just as bad or worse than if too short. Antenna's are tunned to the frequency bandwidth. Now you can get even better tunning if you put a tuneable coil in series with the antenna coil and fine tune it to the exact tunned frequecy but that also has drawbacks will depend on the distance you fine tune to you may loose responce closer or further than the distance you tunned to.
But I will ask him about making the coil length longer just to be sure