The final challenge to invading forces was the lack of a fully integrated, interoperable communications system. Unlike the fighting elements which were organized to conduct operations independent of one another, communications systems were not allowed such freedom. Communications was to have been the glue that would tie together the operation of the four independent United States military service elements. Unfortunately, communications support failed in meeting certain aspects of that mission. It cannot be said that communications capability itself was abundant.
Several participants cite shortages of communications.
For example, uncoordinated use of radio frequencies prevented radio communications between Marines in the north and Army Rangers in the south. As such, interservice communication was prevented, except through offshore relay stations, and kept Marine commanders unaware for too long that Rangers were pinned down without adequate armor. In a second incident, it was reported that one member of the invasion force placed a long distance, commercial telephone call to Fort Bragg, N.C. to obtain C-130 gunship support for his unit which was under fire. His message was relayed via satellite and the gunship responded. Several factors have been cited as the cause of the communications problems which were confronted in Grenada.