• One main type of transmitters is the keyed-oscillator type. In this transmitter one stage or tube, usually a magnetron, produces the rf pulse. The oscillator tube is keyed by a high-power dc pulse of energy generated by a separate unit called the modulator. This transmitting system is called POT (Power Oscillator Transmitter). Radar units fitted with an POT are either non-coherent or pseudo-coherent.
   
• Power-Amplifier-Transmitters (PAT) are used in many recently developed radar sets. In this system the transmitting pulse is caused with a small performance in a waveform generator. It is taken to the necessary power with an amplifier followingly (Amplitron, klystron or Solid-State-Amplifier). Radar units fitted with an PAT are fully coherent in the majority of cases.
   
  A special case of the PAT is the active antenna.

  • Even every antenna element
  • or every antenna-group

  is equipped with an own amplifier here
   

Pictured is a keyed oscillator transmitter of the  radar unit.
The picture shows the typical transmitter system that uses a magnetron oscillator and a waveguide transmission line. The magnetron at the middle of the figure is connected to the waveguide by a coaxial connector. High-power magnetrons, however, are usually coupled directly to the waveguide. Beside the magnetron with its magnets you can see the modulator with its thyratron. The impulse-transformer and the pulse-forming network with the charging diode and the high-voltage transformer are in the lower bay of this rack.

The actual transmitter for the HUTCHISON-MILIONE Philadelphia Experiment will be somewhat different, but

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