To the Editor:

The colorful canard that Adolf Hitler's last name was ''originally'' Schicklgruber continues to live on. I'm referring to your April 14 ''About New York'' column on the third reunion of the Mobile Radio Broadcasting Companies of World War II - the psychological warfare experts who were responsible for boosting our morale while demoralizing the enemy by using lies or the truth - whichever was more effective.

In the case of Hitler's presumed last name, it seems a lie was more effective, perhaps because ''Schicklgruber'' sounds more ridiculous than ''Hitler,'' even today. Therefore, the lie lives on, being more preferable than the truth. This may be the most enduring success of our psychological warfare experts.

As you report it, Hans Habe, leader of the Broadcasting Companies and post-World War II novelist, was responsible for having ''broken the story that Hitler's original name was Schicklgruber.''

Almost 40 years ago, however, in ''Hitler, A Study in Tyranny,'' which remains a standard biography of Hitler, Alan Bullock exploded this myth. Bullock noted that Hitler's father, Alois, had been born out of wedlock to Maria Anna Schicklgruber.