Tower Light

The Tower-Light is a microprocessor based system designed to monitor the status of obstruction lights, used on many broadcast and communication towers. The system will monitor up to eight beacon bulbs and eight marker bulbs: monitoring processing allows controlling all lamps from a single point, including flasher operation. All outputs are opto-isolated for lightning protection when connected to external remote site monitoring equipment. With all lights operating on the tower, the monitor automatically calibrates itself for the number of bulbs in the system.
The unit is specifically designed for broadcasters: great consideration especially for the fault tolerance and twilight sensor fault.


  • Total monitoring of beacon tower lighting systems
  • One key press auto-calibration
  • Individual alarm outputs for power supply, beacon
  • General alarm output for photocell and light
  • Easy to install - installs inside the transmitter building, even if the lighting control equipment is located at the tower
  • Insures total lighting compliance
  • Alarms for single bulb failure (marker and beacon), beacon flash rate or on/off ratio outside of FAA specifications and photocell failure.


  • Compact design
  • Easy installation

Sample method

Current transformer microprocessor controlled monitoring


  • On beacon lamp and/or flasher failure or user selectable hours of no activation
  • On side marker lamp failure, or user selectable hours of no activation

Alarm outputs

  • Photocell failure
  • Flasher failure (alarms for continuous on or off, duty cycle tolerance and flash rate tolerance)
  • Bulb failure (separate alarm outputs for beacon and marker failures)

Technical specification

Power Supply: 9 ÷ 15 VDC
Input Current: 200 mA, 2.5 W Standard
FCC FAA Advisory Circular 70/7460 - 1, Chapter 2 Dimensions
Size: 6 L x 12 H (board size)


TWL-270 Tower-light Metering System