Silver Strand Training Complex 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 . the antenna is still in place , even though it was scheduled to be removed in fiscal year 2007 . Presently the base is subordinate to Naval Base Coronado and commanded by that base ' s Commanding Officer . History . Naval . Initially created in 1920 as the Navy Radio Compass Station , it was renamed in 1940 as the Navy Direction Finder Station when a permanent direction finding station was established . In 1943 , thirty WAVES were stationed there , culminating in 1945 with a total of 112 WAVES ; there they engaged in SIGINT . By 1953 , it was known as Naval Radio Receiving Station Imperial Beach , and in 1965 it received its well known Wullenweber Circular Disposed Antenna Array , a AN / FRD - 10 . The last of its type to be built , it ceased operation in 1999 . Army . In 1942 , the United States Army took ownership of 412 . 14 acres in Coronado Heights and designated it Fort Emory in honor of BG Emory , itself being subordinate to Fort Rosecrans , being manned by the 19th Coastal Artillery . Armament of the base consisted of four 155mm guns of Battery Imperial , which was superseded by the two 6 inch guns ( M1905 ) of Battery Grant . Coastal radars were authorized in 1943 . Construction of a 16 inch battery were completed in 1944 , however the guns were never mounted ; these guns would have supplemented another 16 inch battery , Battery Ashburn at Fort Rosecrans . The land upon which the fort was located was turned over to the Navy in 1947 , with a single army family as caretaker of the facilities which was declared surplus a year later ; in 1950 it was finally transferred to the Navy integrating with the Imperial Beach Radio Station . Operations . Today the facility provides an excellent training environment with waterborne approaches from both the Pacific Ocean and San Diego Bay sides . Offshore the " Coronado Roads " area is used for ship systems testing . The city - like layout of the base also provides a realistic site for critical urban warfare training . In 2010 , the Navy proposed increased training , including mine - sweeping training , amphibious operations , as well as special warfare operations . This faced opposition during public hearings by environmentalist , due to possible impact upon the California Least Tern , San Diego fairy shrimp , and to a lesser extent the Western snowy plover . Later that year new warning signs were put up by the Navy warning of increased training , and of endangered species . A ten - year - long , 818 - page environmental impact statement was released relating to this proposed increased activity , it was created with the assistance of the United States Fish and Wildlife Service . In an unrelated proposal , the bases water area will be used for training by the Littoral Combat Ship s for antisubmarine warfare ; the Navy has filed its impact upon wildlife with NOAA as it relates to the Marine Mammal Protection Act .