recycle bin not getting populated

Upgraded a database to 10.2.0.4 from 9.2.0.8. Trying out some 10g features and notice recyclebin is not working.

SQL>
SQL> create table jb (f1 number);

Table created.

SQL> drop table jb;

Table dropped.

SQL> select * from DBA_recyclebin;

no rows selected

SQL>     Jeffrey Beckstrom
Database Administrator
Greater Cleveland Regional Transit Authority 1240 W. 6th Street
Cleveland, Ohio 44113

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