AM Directional Controllers

  • Customized to your station's transmitters and antenna system
  • Optional custom power relay cabinet 
  • Two-piece aluminum panel and shelf design with engraved control and indicator labels
  • No screens to navigate, nothing to program



Our Design


These space saving PLC-based systems are built on an aluminum panel and shelf unit. Front panel indicators show pattern and transmitter in use, and position of all RF contactors in the system. And like all of our controllers, no user programming is required.


Our AM directional controllers offer a safe switching solution to protect expensive AM contactors. The controllers use timed sequences to remove RF power, move the contactors and verify positions before RF power is restored. There is also protection for a test load, as the controller's load interlock circuit will not allow the off-air transmitter to operate unless the load's air or water is running. 


The control systems are custom designed for your station's towers, patterns, transmitters and test loads. Each controller features key switch selected local-off-remote modes, as well as an emergency bypass mode. Front panel indicators and the contactor position tally system are powered by dual redundant 24 volt power supplies.


The PLC Difference

All Tunwall Radio controllers contain a programmable logic controller. PLCs can replace any number of relays, saving space and hardware expense. PLCs are designed to perform in industrial environments, which typically present several challenges to electronic equipment; heat, dust, vibration, magnetic fields, and power line transients. The PLCs in our systems are microprocessor controllers, built into a convenient package that includes the power supply, input isocouplers, output relays, status indicators, terminals and connectors, and a programming interface. All of the controller's functions are pre-programmed into the PLC.




AM controller control outputs are 24VDC, so no high voltage is wired to the controller. Phasing systems with contactor "pilot" relays can be connected directly. If your station's contactors get 120 or 240 VAC from the control system, an optional small rack mount cabinet with 24 volt power relays to switch the AC is available. We can also design and build a master wiring panel in NEMA enclosure, if you would like to centralize tower wiring before the control rack.


Our AM controllers are built on a two-piece aluminum panel and shelf unit. Labels for front panel controls and indicators are engraved anodized aluminum plates.


If you would like a free quote on a custom AM control system, please fill out our quote request form.

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