Agree with Jeff that the plastic "tail" attached to the mast is probably broken.

With other Hirschman's, I was able to remove the unit from the car, take the cover off, and remove the remains of the "tail." You can then put it back in the car and install a replacement mast.

If it turns out you need additional repair, contact Palo Alto Speedometer - you can find them at hemmings.com.

If you have some basic tools and the time, it's an enjoyable repair.

If you don't fix it, suggest disconnecting the power so that no further damage occurs.

The dealers, I am confident, will want to sell you a whole new antenna unit and labor to replace - proably $600-700.

Good luck.

Chuck