Silver Strand Training Complex (SSTC), formerly known as the Naval Radio Receiving Facility (NRRF), is the premier training facility for U.S. Special Operations Forces. Located between Imperial Beach and Silver Strand State Beach near San Diego in southern California, USA, this facility is known by locals as the "elephant cage" which is a nickname for the large Wullenweber direction finder antenna. The antenna was used to provide direction finding, primary communication links for U.S. Navy submarines.