To replace a Liberty radio antenna will require an adaptor. Part # #6201 a/k/a hummer adaptor
I found it here "Speed and Truck World Estore Your Parts Source"
#6201 and it is same as Hummer, we got them in stock now. There about $4.00 plus shipping and handling.
I suggest ordering 2 at a time.
http://www.speedandtruckworld.com/estore/these folks are also a good source for other parts. Shop is located in Fort Lauderdale Florida
Oh don't put on that shorty antenna, they have poor reception.
Get the 31 inch Black antenna replacement from Autozone. It has the wire wrap on it. Works as good as the OEM but looks much better.