Control centers are the backbone of all cellular networks. To simplify cable installation and antenna mounting in these centers and mobile command vehicles, the TX RX Control Station Combiner (CSC) product line has been spawned. These products are especially designed for use with very-high-frequency (VHF), ultra-high-frequency (UHF), and 746-to-960-MHz communications systems. The devices target the following frequency ranges: 132 to 174 MHz, 380 to 520 MHz, and 746 to 869 MHz. The 746-to-869-MHz combiner, for example, boasts Tx-Tx isolation of more than 70 dB typical and a minimum of 60 dB. The isolation is the same for Ant-Tx. The Tx-Rx and Rx-Rx isolation are both 70 dB typical and 60 dB minimum. The device's return loss is typically greater than 14 dB. To provide operation on two-antenna configurations (one Tx and one Rx) or through a duplexer to a single antenna (Tx/Rx), single antenna-port mobiles may be connected to this combiner. All three combiners claim to have no limitations as far as minimum Tx-Tx separation is concerned. Their goal is to significantly reduce tower clutter and loading issues. They also promise to provide frequency agility without the tuning requirements that were previously needed. Using power attenuators and signal-combining techniques, the short-haul control-station combiners provide fixed isolation between radio units.
Bird Technologies Group, 29100 Aurora Rd., Suite #400, Solon, OH 44139; (440) 248-1200; FAX: (440) 248-3790, Internet: www.bird-technologies.com