Model TSN-3

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TSN-3 Thermal Sentry

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Thermal Sentry

The Thermal Sentry indicates transmitter operating efficiency by monitoring the air temperature difference across the transmitter. Thermal efficiency can warn of problems such as clogged air filters, failed cooling blowers and antenna icing before damage occurs to the transmitter.

The TSN-3 uses two precision sensors to measure the temperature at the air intake and exhaust points of the main transmitter cabinet. The temperature differential is displayed on the front panel LED display.

An alarm can be set to provide a warning when the temperature goes out of range. The alarm status is indicated by a front panel LED indicator, an optional audible alert and a relay closure. The output relay can be used to signal other equipment of a potential failure condition.

Analog output connections are available for intake, exhaust and differential temperature. These outputs can be monitored by a remote control system such as the RFC-1/B Remote Facilities Controller.


  • Adjustable sensor calibration
  • Adjustable alarm trip point
  • Fahrenheit or Celsius output
  • Maximum sensor temperature +230°F (+110°C)
  • Maximum differential temperature +199°F (+93°C)


The standard temperature sensors measure degrees Fahrenheit. Sensors for Celsius readings are available by request and may require a short lead time.

The temperature sensors for the CTI-2 consist of a small PC board with three screw terminals. A small piece of heat-shrink tube is included to electrically insulate the sensor. The installer provides appropriate three-conductor, shielded cable to connect the sensors in the appropriate locations.