By Dick Bilotta, Communications & Power Industries
Some types of microwave receiver protectors are limited life products. This is an area which is often not well understood by those who use them. Nevertheless, it is an important factor to take into consideration when choosing a receiver protector during system design. Failure to do so could result in needless extra operational and maintenance costs as well as the possible failure of a component at a critical moment. This article will give the reader a better understanding of the underlying concepts of receiver protector life and how they apply to actual performance. To begin, not all types of receiver protectors have limited life. Only those products that contain some form of plasma limiter (TR tubes, TR Limiters, Pre-TR tubes, etc.) have a limited life. All-solid-state products (Diode limiters, switches, ferrite limiters, etc.) have no natural wear-out mechanism and are not part of this discussion.
TYPES OF LIFE
There are two types of life: operating life and storage life. Operating life is the number of hours that the unit can be expected to function in the system under its normal operating conditions before its performance degrades to the point where it no longer meets the specifications. The actual operating life of any tube depends on many different factors and environmental conditions. These are discussed below. Storage life refers to the period of time that a new, unused unit can be stored with no degradation in performance.