The second spin-off was W \* A \* L \* T \* E \* R \* , which was about Walter `` Radar '' O'Reilly ( Gary Burghoff ) . W \* A \* L \* T \* E \* R was the pilot for a television series that was not picked up . It would have featured Gary Burghoff reprising the role of Walter O'Reilly , who is no longer referred to as `` Radar . ''