the r&s®fk4150u has an extremely fast setting time for silent channels and allows frequency hopping operation in line with secom-h.
for protection against overvoltage as produced by lightning strokes to the antenna, the r&s®fk4150u output is provided with lightning protection
tuning functionalitythe r&s®fk4150u offers a 'silent tuning feature' over the entire frequency range from 1.5 mhz to 30 mhz.
before this feature can be used, the atu must be connected to the antenna to "learn" its characteristic. learning takes place in an user-defined frequency range in the hf band (1.5 mhz to 30 mhz). the atu "learns" the antenna characteristic by obtaining tuning data at certain fixed frequencies in the hf frequency band. once the tuning data for these frequencies is known and stored, the typical silent setting time of the atu is less than 5 ms.
the advantage for the user is low probability of intercept (lpi), since atu frequency setting is performed very quickly and without any emission of rf power.
repeated tuninga change in environmental conditions may slightly alter the actual antenna tuning data as compared to the stored data.
the quality of antenna matching is therefore checked during operation by means of an integrated vswr measuring device. if the required vswr (<1.5:1) is not attained, the atu can be retuned (nonsilent mode) in less than typ. 100 ms.
bitethe atu is included in the continuous monitoring of the entire system so that deviations from the normal operating status are displayed on the control unit.
emc and overvoltage protectionall circuit boards are equipped with emc filters. for protection against overvoltage as produced by lightning strokes to the antenna, the r&s®fk4150u output is provided with lightning protection.