Radar O'Rielly

Corporal Walter Eugene 'Radar' O'Reilly was the Company clerk of the 4077th M*A*S*H. He was played by Gary Burghoff in both the film and series (season 1 - 8), he is the only main actor to reprise his role from the movie for the series.

"Radar" Nickname
Few who knew Corporal O'Reilly called him anything except "Radar." His mother called him "Walter." His nickname is well earned. He had the uncanny ability to know things are going to occur shortly before they happen. In the series, this manfested in two main ways. Radar would always be the first to know when a chopper was coming with new wounded. He would pause, as if listening and then announce, "A chopper's coming." Often, someone who wasn't used to him might remark, "I don't hear anything." He would replay, "Wait for it." After a moment there were be the sound of helicopters and the staff would start rushing. The staff would just take his word for it.

His ability also came into use in the way he worked with his commanders. Lt. Col Henry Blake, found Radar's ability frustrating. Col. Blake would shout to the next room, "Radar!" only to be startled to find Radar was already standing next to him with the papers Blake had intended to ask for in hand. Blake would go on to make the request he intended anyway, and Radar would repeat the request along with him, or just finish his sentence. This further frustrated Blake who would remark that he'd like, just once, to be able to make a request before it was fulfilled.

While Radar did the same with Colonel Potter, Potter took it stride and would let Radar finish his sentences. Radar likely felt closer to Col. Potter than he did Col Blake. Potter would often offer him fatherly advice. In season 4, "Dear Mildred" Radar gifted Col. Potter with a horse, leading it into his office. Col. Potter had begun his career in the horse cavalry. Radar said he gave the horse, who would be named, "Sophie," to the Colonel so he could take care of it, but Col. Potter's heart was touched, even when he slipped the droppings the horse left in his office, calling it a "tip toe through the tulips."

(spoilers) Abyssinia, Henry
Radar had one of the most touching scenes in the series at the end of the third season. Henry Blake (McLean Stevenson) was leaving the series with the story that he was being discharged after fulfilling his time and was going home. Most of the episode revolved around celebrating that Henry was getting what everyone wanted, to go home. The episode had the usual comic tone. This changed quickly. After Henry is flown away, and once again the staff is working in surgical room. Radar enters the room, shaken and not wearing a mask. The news he was to deliver was kept from the actors and most of the staff. Henry Blake's plane was shot down. "There were no survivors."

Good Bye, Radar
Radar (Gary Burghoff) left the series in season 8, in a two parter titled, "Good Bye Radar." He had already been appearing in fewer episodes, feeling burned out in the series. The plot was that he was given a hardship discharge to go back and take care of his mother and the family farm. Radar initially fought the discharge claiming that the camp couldn't survive without him, even purposely missing a ride home. This attitude was met with outrage from the rest of the staff, especially Hawkeye, whose tone for the first time turned harsh against Radar, whom he always had protected.