Delta Electronics, Inc., Model SLS-4 Antenna Switching Matrix
Introduction
The Delta Electronics Model SLS-4 Strip Line Switch is a manually controlled 50 Ohm switch matrix for connecting any of a number of transmitters to any of a number of antennas. The SLS-4 is ideally suited for use with 10 kW average power transmitters and with 3:1 maximum VSWR antennas. The switch design provides a compact system with excellent power rating, low insertion VSWR, low insertion loss, and high isolation characteristics.
The design of the switch makes it inherently impossible to connect more than one transmitter to one antenna or to connect one transmitter to more than one antenna. An interlock circuit that exactly duplicates the RF circuit operates to remove power from the RF circuit prior to switching. At the completion of the switching sequence, the interlock circuit is rerouted and reconnected to protect the new RF circuit. An indicator circuit provides a dry contact closure for each transmitter to antenna connection for remote indication of the switch status.
This manually operated switch incorporates a motorized wiring harness and can be easily converted to motorized operation.
Description
The Model SLS-4 Strip Line Switch comprises a matrix of horizontal transmission lines (rows), vertical transmission lines (columns) and crosspoint switching elements at each row-column intersection. Each crosspoint consists of row and column leaf springs and a rotor contact. In the Thru position, RF power flows through the crosspoint to the adjacent row leaf spring and adjacent column leaf spring, and the grounded rotor contact shields the transmission lines from each other. When the rotor contact is rotated 90 degrees to the Turn position, the conductive shoulders of the rotor contact connect the row transmission line to the column transmission line and perform the desired switching. The rotor contact also disconnects the adjacent row and column leaf springs from the switched circuit. This action removes transmission line stubs from the RF circuit and prevents paralleling of inputs or outputs.
All auxiliary interlock and indicator switching is performed by a wafer switch deck incorporated in the manual switch or motor actuator located on the rear of each switch module. The rotor contact is mechanically linked to the manual switch or motor actuator. Thus, the rotation of the rotor contact automatically performs the auxiliary switching.
The protective interlock circuit exactly duplicates the RF circuit through the switch. The timing of the interlock switching prohibits the occurrence of "hot" RF switching. The first 30 degrees of rotation opens the established interlock path removing RF power from the crosspoint. The second 30 degrees of rotation accomplishes RF path switching. The last 30 degrees of rotation establishes the interlock circuit to the new RF path and permits power to be applied.
The SLS-4 also provides a bussed row and column indicator circuit for remote matrix status. The indicator circuit switch closes when the crosspoint is in the Turn position and opens when the crosspoint is in the Thru position.
The SLS-4 provides the capability for remotely controlled switching of all crosspoints. The switch may be initially equipped for manual operation of all crosspoints, or for motorized operation of some or all crosspoints. All motorized crosspoints are capable of manual override operation. Manual switch controls are accessible from the front of the switch.
Configuration
Configuration A:
This configuration has the column connectors on the top of the switch and the row connectors staggered on opposite sides of the switch facing to the rear.
Standard Features
Interlock Isolation Assembly
The SLS-4 includes the Model IIU Interlock Isolation Unit to provide an isolated interlock interface to the transmitters. The interlock circuit of the switch is a single wire circuit with a common return. Since the interlock circuits of many transmitters are above ground and may not be connected together via the switch interlock harness, the IIU relays provide isolated interlock switching for each transmitter. The IIU also provides an additional contact closure to a common for each valid interlock circuit. This contact closure may be monitored by a control system for remote indication of the interlock circuit status.
Interlock Keylock Switches
The SLS-4 is equipped with interlock keylock switches installed in the output interlock circuit. The keylock switches provide positive lockout of the interlock circuit and the corresponding RF output. The key can be removed only when the keylock switch is in the open interlock circuit position. Each keylock switch may be supplied with either different keying or identical keying.
RF Connectors
The standard RF termination is 1-5/8" EIA male flange plus an LC connector on the top, and some N connectors.
Optional Features
Key Operated or Automatic Antenna Grounding
Our units have Key Operated Grounding:
The switch may be equipped with a special row or column of grounding crosspoints that ground each output terminal when the associated crosspoint is in the Turn position. This feature allows an antenna to be grounded at the switch for isolation during maintenance activities or for static discharge when the antenna is not connected to a transmitter. With this option, the row or column adjacent to the output terminals is equipped with grounding crosspoints. These antenna grounding crosspoints may be equipped with either key operated rotor assemblies for manual grounding or with actuators for automatic grounding. The key operated grounding crosspoints can only be manually operated and can only be operated using the unique key for that crosspoint. The key can be removed only when the crosspoint is in the antenna ground position. The motorized antenna grounding crosspoints are controlled by the associated Model MCU-8 or MCU-9 Matrix Control Unit to automatically ground the antenna upon disconnection of the antenna from a transmitter.
SLS-4 SPECIFICATIONS
| Frequency Range: | DC to 32 MHz |
| Impedance: | 50 Ohms Coaxial |
| Power Rating: | 30 kW Average, 100 kW Peak
Unity VSWR, 5000 Ft Maximum Altitude(To determine the power rating for other values of load VSWR, divide power rating by load VSWR. Consult factory for higher altitude derating.) |
| Insertion VSWR: | 1.10 maximum for matrix sizes up to 40 x 30 |
| Insertion Loss: | Size Loss
10 x 10: 0.10 dB
20 x 20: 0.18 dB
30 x 30: 0.26 dB
40 x 30: 0.30 dB
(Insertion loss for all models at 32 MHz is 0.025 dB + N(0.004) dB. N equals the number of modules in the path. A 10 x 10 matrix has 19 modules in the longest path.) |
| Cross Channel Isolation: | 70 dB Minimum |
| Terminations: | Standard: 1-5/8" EIA Male Flange
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| Size: | Self-Supporting: 64.75" high (15 row max) x 17" deep
Height increases by 2.0 inches for each row above 15. Width varies with number of columns. Contact factory for specific size information.
Rack Mounting: 19" or 24" wide standard EIA rack panel x 12" deep. Height varies with number of rows. |
| Weight: | Size Manual
10 x 10: 290 lbs
20 x 20: 600 lbs
(Switch weight varies with options. The table above gives approximate weights for some representative sizes of self-supporting switches.) |
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