HONG KONG, June 14 (Reuters) - Amid reports that China is expanding its electronic eavesdropping capabilities in Cuba - which Beijing has denied - China's evolving military surveillance network has some way to go to match the sweep and reach of the U.S. and its allies, defence and intelligence analysts say. WHAT IS A FOREIGN LISTENING POST? Five defence and intelligence analysts and four diplomats say large-scale military operations, even in peacetime, demand extensive attempts to vacuum up communications and electronic emissions, all part of what is known as signals intelligence (SIGINT). The targets could be, for example, conversations between...