In quadruple diversity troposcatter system, one transmitter and two receivers are connected to each antenna, utilizing dual-polarized feed horns. In the receiver arm, a diplexer including a 3- or 4-port circulator and multlcavity preselectors are provided ahead of the front-end amplifiers. The diplexer introduces 2 to 2.5 dB of insertion loss and the noise figure of the receiver gets degraded by this amount. A modified configuration of the front-end of the receivers has been evolved and tried out. The modified configuration eliminates the noise figure degradation of 2 to 2.5 dB and also utilizes one front-end amplifier for two receivers. A few other advantages also could be realized with this modification. This paper describes the existing arrangement, the modified arrangement and the performance results.
展开▼
