Full disclosu The glider I designed also has the VHF com antenna in the rudder. It is a convenient place to put an effective and efficient quarter-wave dipole in a ship with an all-carbon fuselage.

I've tried using those small flexible antennas in a couple of all-metal gliders, and have been consistently underwhelmed with their performance. I'd suggest you explore options for fixing the existing antenna. If you can pinpoint the place where the coax meets the antenna, it could be that the surgery required might not be that invasive.

Thanks, Bob K.