Model 6740B and Model 6742B
3-1/8″ EIA Coaxial Transfer Switches
Coaxial transfer switches are used to switch transmitters, transmission lines, antennas, dummy loads and auxiliary equipment quickly and efficiently when failures occur, when operating procedures are changed, or during scheduled maintenance periods. They also simplify equipment tuning, testing, and emergency repairs by facilitating quick checks under actual operating conditions.
Many switching requirements in a station are greatly reduced by the use of transfer switches. In complex systems, only one-third or one-fourth as many transfer switches are needed to accomplish the same switching function as a system using SPDT or SP3T type switches. If only three of the terminals in the Model 6740B or 6742B switch are employed, the switch can be used as a SPDT type.
The Models 6740B and 6742B can be pressurized up to 15 lb/sq in (1.1 kg/sq cm). A gas barrier is built into each terminal and an air inlet port is provided.
The Coaxial Transfer Switch provides two isolated interlock circuits for each switch connection that duplicate the RF path exactly. All interlock switches open before the RF contacts open, and close after the RF contacts close to prevent switching with RF power applied. Additional internal switch contacts enable remote control and status indication. All interlock, indicator and control circuits interface the transfer switch through a connector.
The transfer switch can be remotely controlled using either a high level, direct AC main power switching interface or a low level, open collector/contact closure interface. The Model 33630A Coaxial Switch Control Panel controls either a Model 6740B or Model 6742B Coaxial Transfer Switch and indicates the switch connections. The control panel operates with 120 VAC or 220/240 VAC, 50/60 Hz main power and mounts in a standard equipment rack space of 3-1/2″ high by 19″ wide.