HAVANA - Cuba's Communist government has signaled a crackdown on the use of black-market satellite dishes, just over a week after ailing leader Fidel Castro temporarily relinquished power to his brother. "They are fertile ground for those who want to carry out the Bush administration's plan to destroy the Cuban revolution," said the newspaper, the official voice of the government. Such an article in Granma usually signals that action is on the way. Castro said in an August 1 statement that details of his health were a state secret due to the threat of U.S. intervention in Cuba.