Vaughns Magnetrons
Pulse Modulator 3
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This magnetron pulse modulator origionally designed for the 2J21 and 725A magnetron; however since its operating output impedance is 1 K ohm (12KV at 12 amps) it is also useful for driving the 2J50 and the 2J55. What makes this so neat is that of simplicity and relatively lost cost. The high voltage switching is accomplished with a triggered spark gap ( trigatron) which seems to pulse relatively clean. As far as I have been able to roughly measure;  the jitter is about 40nsec or slightly more within several seconds. At shorter time frames the statical jitter appears about half. For my purposes , as a simple magnetron tester) I am very happy with it.
The PFN (see construction detail and schematic) and triggatron test setup is shown in the photo below  (see also  B2Spice simulation and test data)  :
PFN charge/HV input
PFN output (110 ohms)to magnetron mount
Trigger Transformer
trig IN (see driver )
110 ohm Cable ( PFN -to-magnetron mount)
The magnetron PFN pulse modulator is connected to the magnetron mount with a 100 ohm cable assembly to rough match the 110 ohm impedance requirement. It consists of two 50 ohms cables physically laid in parallel but connected in series at each end. One of the cables is insulated with an insulating flexable rubber hose  as shown below:
PFN pulse modulator 
magnetron mount
Magnetron Mount)
The magnetron mount ( see photos) input is designed to match the 110 ohm magnetron pulse transformer primary input.
Early Construction Photo
2J21 magnetron ( without the electromagnet)
magnetron cathode\ minus 12KV input
cathode heater shunt capacitor @ HV output
Follow up Photo
pulse transformer
725A cathode heater shunt capacitor missing
6.3 Volt cathode heater power input
second cathode heater shunt capacitor @ input
CVR magnetron pulse current monitor
PFN drive to transformer input
HV diode
neon bulb RF output indicator
The magnetron mount used with the electromagnet assembly;  725A magnetron being tested:
HV voltage probe for monitoring the magnetron cathode
Experimental Setup;  725A magnetron being tested:
13.75 VDC power supply
screen box for enclosing DSO
trigger generator
trigger driver
trigger driver PS
charging inductor
charging diode
Magnetron Mount  Experimental Configured  for 2J55
Magnetron Mount  Experimental Configured  for Permanent Magnet