PLEASE HELP

HI- CAN ANYONE HELP ME. OUR GRANDSON HAS a FAST LANE WILD FIRE MONSTER TRUCK- the ANTENNA CAUGHT in a BACK WHEEL CAUSING the ANTENNA to COME AWAY from INSIDE the SHELL. IT IS ALL INTACT but DON'T KNOW WHERE to SOLDER BACK on UNDER SHELL. TRANSMITS OVER VERY SHORT DISTANCE NOW. THANKS