DX Engineering A/B Station Selector

The DX Engineering A/B Station Selector Interlocked Coaxial Relay was designed for two-station multi-operator or SO2R contesting from 160 through 6 meters. Two radio inputs and one output for an amplifier, antenna or another relay, allow the AB Selector to function as two interlocked SPST normally open contact coaxial relays when controlled by a user provided SPDT switch or antenna selection automation.

This device is a critical component that enables a single radio to access the shared output port while simultaneously isolating the other radio from that port. With over 80dB of isolation between the selected and unselected ports, there is no danger to the opposite receiver from high energy overload or burnout. In place of a manual switch, the AB Selector can be controlled from a distance, or remotely with automation, to select between two antennas or two remote antenna switches for one station feedline. It can also be used to remotely toggle a transceiver, amplifier or station output to either an antenna switch for normal operations or a dummy load for testing and tuning, instead of using a port on a remote antenna switch for the dummy load.

Two A/B Station Selectors may be configured as a DPDT reversing switch, as shown in Figure 2 of the user manual, useful for switching two transceivers to two different towers, two antenna switches or two amplifiers that are tuned to different bands or segments, for Single Operator Two Radio (SO2R) stations.

Multiple A/B Selectors can be configured for a Multi-2 or Multi-Multi contest station in combination with third-party multi-port antenna switches and band decoders to create an automated band-specific antenna selector system. Contact DX Engineering for more information.

The DX Engineering A/B Station Selector is a drop-in replacement for the legacy TopTen Devices A/B Station Selector. This relay device features excellent port-to-port isolation, low SWR and low insertion loss, and is rated for full legal SSB and CW power on the 160 through 6 meter bands.

This relay features three UHF female/SO-239 connectors, Radio-A, Radio-B and Common and a removable control connector with compression screw terminals. DC voltage input is +12 to 14VDC @ 110mA with sink-to-ground connections for A or B port selection. Neither A or B port is selected when neither A or B control terminal is grounded.

The DX Engineering A/B Station Selector may be used for two different switching systems: one common input to two outputs or two inputs to a single common output. Figure 1 in the user manual shows how to connect a user provided SPST switch and power supply. For example, two radios or two amplifiers connected to A and B, can be switched to connect one antenna or antenna switch on the COMMON.

Conversely, a single radio or amplifier connected to the COMMON port can be remotely switched between two antennas connected to A and B, or between two amplifiers feeding separate antennas. Alternatively, a station may use the switch to select between an antenna and a dummy load.

Additional Features & Specifications

• Frequency Range: 1.8–54MHz

• Power Handling:

1500W SSB/CW

1000W FT8/RTTY

• Throughput SWR:

< 1.1:1 at 30MHz

< 1.15:1 at 50MHz

• Maximum Antenna SWR: 2.0:1

• Insertion Loss:

< 0.03dB at 30MHz

< 0.07dB at 50MHz

• Isolation: > 80dB from selected to unselected port

• Power Requirement: +13.8VDC @ 110mA (nominal)