Calorimetry-Power Measurement

Opti-Cal® Digital Calorimetry

Opti-Cal in 15kW Airload

Opti-Cal in 15kW Airload



The Opti-Cal® true calorimetry system for Altronic air cooled loads calculates power by measuring the infrared emitted by load resistors in air.  One or more calibrated infrared sensors make accurate measurements of system heat. Measurements at thermal-equilibrium are highly accurate.

This system features a projected-power reading, which closely describes the power level at thermal-equilibrium, minutes in advance.

The combination of hardware and OPTIONAL open-source software allows for monitoring of all available measurements, readings, and notices from anywhere on the local network or the internet.  Easily tailor the network backend to suit your needs or use the optional included solution.




  • True Calorimetry:  Measures Infrared-HeatOpti-Cal screen
  • Flow / Pressure Corrected: For varying altitudes and exhaust systems
  • Equilibrium Measurement Accuracy: 4% +/-
  • Backlit Touch Screen
  • Load, cooling and interlock systems are isolated from device
  • Monitor locally or remotely with optional network support

Opti-Cal OPC-3 Demo video


Model 3500 Digital Calorimetry:

CalorimetryThe Model 3500 Digital Calorimetry for Altronic air cooled dummy loads is the first calorimetry of its kind for measuring RF power dissipated in an air cooled dummy load. The systems calculate the RF power by measuring air flow and differential air temperature between the inlet and outlet. The unit also features a projected power reading, which provides the user with the projected power prior to the total SYSTEM reaching equilibrium. This unit is available in Altronic air cooled dummy loads from 5kW to 75kW.

A water based system is also available for water cooled loads from 5kW to 300kW. Both systems operate under a PC or CE environment.


  • Accuracy < 4% FSR Repeatability < 2% FSR Sensor digitized to reject RF interference
  • Contact Factory for special options
  • Note: For use on higher power loads, consult factory.


Analog / Power Test Load System:

Power Test BoardThe Altronic Research Power Test Load System comes ready to connect to an OMEGALINE Load in power ratings from 5kW to 200kW. It includes a simple and reliable calorimetry and time delayed interlock. All items are attached to a painted aluminum panel ready to be installed in your transmitter area. These instruments assembled together provide you with the information you need and protect your transmitter at the same time.

Note: Items can be bought separately.


Calorimetry Components:

  • 2 TW-2 Thermometer Well (A)
  • 1 TC-1 Thermometer (B) scaled -2°C to + 68°C with 0.2° Divisions & 1 TC-2 Thermometer 25°C to 105°C
  • FM 134 Flowmeter (C) with any 10 to 1 scale and accuracy of ± 2%
    Full scale

Time Delayed Interlock Components:

  • FS 234 Magnetic Flow Switch (D) to sense coolant flow
  • CB 1-A Control Box (E) to activate shutdown if a low coolant flow develops

Other Accessories Not Shown:

  • TC-2 Thermometer 25°C to 105°C
  • TW-2 Thermometer Well 3/4″
  • FS134 Paddle Activated Flow Switch
  • Y-Style and T-Style Strainers for Water Loads Above 100kW
  • Note: Items can be bought separately