NEW YORK, Feb 22 Currency speculators turned long on the U.S. dollar for the first time since early December in the latest week, according to data from the Commodity Futures Trading Commission released on Friday. The value of the dollar's net long position was at $1.481 billion in the week ended Feb. 19 versus a net short position of $3.02 billion in the previous week. The last time U.S. dollar positioning was net long was in the week ended Dec. 4. Much of the dollar's gain came at the expense of the British pound. To be short a currency is to bet it will decline in value, while being long is a view its value will rise. Speculators also increased bets against the Japanese yen. Plans for aggressive monetary easing in Japan have sent the yen down sharply against the dollar and euro in recent months. The Reuters calculation for the aggregate U.S. dollar position is derived from net positions of International Monetary Market speculators in the yen, euro, British pound, Swiss franc, and Canadian and Australian dollars.