In military procurement, Commercial Off The Shelf (COTS) are becoming more and more common, with growing adoption of technologies derived from commercial standards. COTS are very appealing as they simplify procurement, allowing rapid deployment and cost savings. On the other hand, COTS usually need to be customized and adapted to the battlefield requirements, especially with respect to security and reliability. When fielding a new COTS technology, harmonization with existing legacy and military-specific solutions needs to be taken into accout. Tactical communications are strongly characterized by the co-existence of COTS-derived solutions and military standards. This allows virtually unlimited degrees of freedom when designing a tactical network and leads to a potentially highly fragmented topology, where different fielded technologies are noninteroperable or poorly integrated. For this reason, an accurate planning and testing of integration prior to fielding are required for heterogeneous networks. In this paper we describe a testbed for tactical communications based on an heterogeneous network, deployed in Livorno (Italy) and created from a cooperation between CSSN ITE, a research center of the Italian Navy, Selex ES and ELMAN. The testbed integrates different architectures not only limited to tactical communications, but also comprising remote sensing devices, networking solutions and specialized software applications. The testbed, also thanks to its location, provides a unique environment to set up relevant test scenarios for maritime and littoral operations. Its architecture is modular for rapid integration of different technologies and centralized management of the experiments, in order to be customizable for different kind of test campaigns.