John Hutchison & Ronnie
The Philadelphia Experiment
The radar transmitter produces the short duration high-power rf pulses of
energy that are radiated into space by the antenna. The radar transmitter is
required to have the following technical and operating characteristics:
- The transmitter must have the ability to generate the required mean RF
power and the required peak power
- The transmitter must have a suitable RF bandwidth.
- The transmitter must have a high RF stability to meet signal processing
- The transmitter must be easily modulated to meet waveform design
- The transmitter must be efficient, reliable and easy to maintain and the
life expectancy and cost of the output device must be acceptable.
The radar transmitter is designed around the selected output device and most
of the transmitter chapter is devoted to describing output devices therefore:
- 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
- A special case of the PAT is the active antenna.
is equipped with an own amplifier here
- Even every antenna element
- or every antenna-group
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,