Ameritron RCS-4 Control Box Modification for remote QTH
This is a modification to a Ameritron RCS-4 control box which is using coaxial cable to switch four antennas. The modification allows you remotely select one of the four antennas by using two web relays, two open collectors or two optocouplers. The modification is implemented by redesigning the control box PCB board. When the rotary switch is turned to the REMOTE position the antenna selection is controlled by the two RCA contact inputs. This REMOTE state is indicated with the added green LED. The original local antenna selection can still be used by turning the rotary switch to a desired antenna.


Original control box front panel

Modified control box - Green remote LED added

Original rear panel

Modified rear panel with two RCA jacks for remote control.
Grounding B-A contact inputs: OFF-OFF=ANT1, OFF-ON=ANT2, ON-OFF=ANT3, ON-ON=ANT4.
The required sink current is 2.3mA, so you can use eg web relays, open collectors or optocouplers.

Original PCB top
Redesigned PCB top

Original PCB bottom
Redesigned PCB bottom, spare 1A fuse on the left.


Redesigned PCB board installed

Original mains transformer and RFC is used

Spare fuse on PCB

RCA connectors in the rear panel