Operational Experience of Solid-State Replacement for Hard Tube Modulators

Air defense radar systems in the medium power class (approximately 125 kW average power) have been in service for over thirty years. These legacy systems are based on physically large vacuum tube switching components facing obsolescence in the manufacturing world. To address component availability and reliability, new solid-state replacement modulator designs have been deployed in a number of systems in the Europe NATO backbone air defense system. The early operational experience of these modulator system upgrades has been positive and has demonstrated operational integrity and system reliability improvements at the installed sites. A system description of the replacement modulator and some fundamental performance will be presented. Early reliability performance data will be discussed as well as potential improvements for increasing the system availability to even higher levels.